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Interface Science and the Formation of Structure
Published in Jeffrey P. Simmons, Lawrence F. Drummy, Charles A. Bouman, Marc De Graef, Statistical Methods for Materials Science, 2019
Interface science for surfaces, grain boundaries, and hetero-phase interfaces provides the underlying physics for the formation of structures and microstructural development. Thermodynamically, interface energies dictate the triple-junction geometry and wetting configuration, and the anisotropy in interface energies produces faceting and controls crystal morphology. Moreover, interface energies, as extensive thermodynamic variables, vary with changes in thermodynamic state variables such as temperature, pressure and chemical potentials, which will subsequently result in changes in various microstructural features. A variety of first-order and continuous faceting/roughening, wetting and complexion transitions may occur at interfaces, leading to accelerated changes in interfacial energy, structure, chemistry, and morphology as well as related microstructural features. Furthermore, interfaces can control microstructural evolution via variation in thermodynamic driving forces and, often more importantly, drastic changes in interfacial transport kinetics (e.g., grain boundary diffusivity and mobility), particularly with the occurrence of first-order interface transitions.
Jointed rock mass characterization using field and point-cloud data
Published in Vladimir Litvinenko, Geomechanics and Geodynamics of Rock Masses: Selected Papers from the 2018 European Rock Mechanics Symposium, 2018
Miloš Marjanović, Marko Pejić, Jelka Krušić, Biljana Abolmasov
Kinematic conditions were analyzed by approximating the entire slope face as a continual surface with elements 130/68°. The 68° angle was an average measured inclination for 10 regularly spaced profiles (e.g. A-A´ in Fig. 4) along the slope. Since the slope geometry is relatively regular and flat no further faceting was necessary. The following global kinematic conditions for the slope apply: Planar block failure is not globally (for the entire slope) relevant, as neither of the averaged planes do not meet the Panet/Markland’s criteria. However, due to the local arching and divergence of planes close to the fault zone, singular local planar failures are possible.Wedge failure occurs between the Sets 1 and 4, as well as 2 and 4 (to a lesser degree), and globally influence the stability of the slope, as well as locally (Fig. 4).Toppling is possible with the Set 3, both globally and locally in some profiles, wherein the Set 1 plays an important role in undercutting the slabs for potential toppling.
Jointed rock mass characterization using field and point-cloud data
Published in Vladimir Litvinenko, EUROCK2018: Geomechanics and Geodynamics of Rock Masses, 2018
Miloš Marjanović, Marko Pejić, Jelka Krušić, Biljana Abolmasov
Kinematic conditions were analyzed by approximating the entire slope face as a continual surface with elements 130/68°. The 68° angle was an average measured inclination for 10 regularly spaced profiles (e.g. A-A′ in Fig. 4) along the slope. Since the slope geometry is relatively regular and flat no further faceting was necessary. The following global kinematic conditions for the slope apply: Planar block failure is not globally (for the entire slope) relevant, as neither of the averaged planes do not meet the Panet/Markland’s criteria. However, due to the local arching and divergence of planes close to the fault zone, singular local planar failures are possible.Wedge failure occurs between the Sets 1 and 4, as well as 2 and 4 (to a lesser degree), and globally influence the stability of the slope, as well as locally (Fig. 4).Toppling is possible with the Set 3, both globally and locally in some profiles, wherein the Set 1 plays an important role in undercutting the slabs for potential toppling.
Vibration prediction and experimental validation of a rotary compressor based on multi-body dynamics
Published in Mechanics Based Design of Structures and Machines, 2023
I-Cheng Wang, Yu-Ren Wu, Yiin-Kuen Fuh
“Parasolids” in the geometry library with the faceting tolerance of 300 is used for 3-D contact definition in ADAMS to increase the solving accuracy in “Contacts” of the proposed MBD model. The “WSTIFF” integrator and “SI2” formulation are adopted in the “Dynamics” solver settings to solve the contact forces more stably and precisely. The crankshaft is accelerated from 0 rpm to a steady rotational speed of 3420 rpm in 0.2 s. The duration of the simulation is set to 0.5 s and 51,300 time-steps are considered to obtain enough resolution for the vibration signals. The simulation result shown in Figure 5(a) indicates the tangential acceleration at the measuring point 2 on the compressor casing. Periodic pulsation in the acceleration is obvious in the time-domain result. In addition, the frequency spectra for acceleration are obtained through the fast Fourier transformation (FFT) and the Hanning window filter. The base frequency of 57 Hz and its harmonic frequency related to compressor speed is generated. Finally, these simulated acceleration results are compared with the experimental results.
Principle of corresponding states for hard polyhedron fluids
Published in Molecular Physics, 2019
We note several interesting features of the hard-polyhedron equation of state in Equation (7). The packing fraction dependency is similar to that of the Carnahan-Starling hard-sphere equation [16]. This is expected as we normalised the equation relative to an inscribed sphere. Additionally, there are two dimensionless prefactors. The term can be interpreted as a first order correction that accounts for the polyhedron occupying a larger volume as compared to the inscribed sphere. By definition since the inscribed sphere will always have a smaller moment of inertia than its encapsulating polyhedron. Thus, physically accounts for particle anisotropy through an explicit reduction in orientational symmetry due to the presence of faceting of a hard polyhedron. Equation (7) provides a universal equation of state for convex polyhedra and is the major result of this section.