Direct Numerical Simulation of Interfacial Flows: Implicit Sharp-Interface Method (I-SIM)

In recent work (Nourgaliev, Liou, Theofanous, JCP in press) we demonstrated that numerical simulations of interfacial flows in the presence of strong shear must be cast in dynamically sharp terms (sharp interface treatment or SIM), and that moreover they must meet stringent resolution requirements (i.e., resolving the critical layer). The present work is an outgrowth of that work aiming to overcome consequent limitations on the temporal treatment, which become still more severe in the presence of phase change. The key is to avoid operator splitting between interface motion, fluid convection, viscous/heat diffusion and reactions; instead treating all these non-linear operators fully-coupled within a Newton iteration scheme. To this end, the SIM’s cut-cell meshing is combined with the high-orderaccurate implicit Runge-Kutta and the “recovery” Discontinuous Galerkin methods along with a Jacobian-free, Krylov subspace iteration algorithm and its physics-based preconditioning. In particular, the interfacial geometry (i.e., marker’s positions and volumes of cut cells) is a part of the Newton-Krylov solution vector, so that the interface dynamics and fluid motions are fully-(non-linearly)-coupled. We show that our method is: (a) robust (L-stable) and efficient, allowing to step over stability time steps at will while maintaining high-(up to the 5th)-order temporal accuracy; (b) fully conservative, even near multimaterial contacts, without any adverse consequences (pressure/velocity oscillations); and (c) highorder-accurate in spatial discretization (demonstrated here up to the 12th-order for smoothin-the-bulk-fluid flows), capturing interfacial jumps sharply, within one cell. Performance is illustrated with a variety of test problems, including low-Mach-number “manufactured” solutions, shock dynamics/tracking with slow dynamic time scales, and multi-fluid, highspeed shock-tube problems. We briefly discuss preconditioning, and we introduce two physics-based preconditioners – “Block-Diagonal” and “Internal energy-Pressure-Velocity Partially Decoupled”, demonstrating the ability to efficiently solve all-speed flows with strong effects from viscous dissipation and heat conduction

Track A Basic Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd

A pattern recognition approach to 14-epi-hydrophenanthrene core of the morphine alkaloids based on shikimic acid

10.1016/j.tet.2011.03.063Tetrahedron67193363-3368TETR

Zonotope-based interval estimation for discrete-time linear switched systems

This paper is concerned with the interval estimation for discrete-time linear switched systems affected by unknown disturbances and noises. A novel interval estimation approach is proposed by integrating robust observer design with zonotopic techniques. By introducing L? technique into observer design, the proposed approach is effective in attenuating the influence of unknown disturbances and noises, and improving the accuracy of interval estimation. Based on the designed observer, the interval estimation can be obtained by using zonotopic analysis. Numerical simulation results are conducted to demonstrate the feasibility and effectiveness of the proposed approach. Copyright © 2020 The Authors. This is an open access article under the CC BY-NC-ND licens

Deformation capturing of concrete structures at elevated temperatures

Reliable deformation measurement is required for proper quantification of fire performance of concrete structures. Predictive capability of models for many critical properties, including Young's moduli, stress-strain relationships and load-induced thermal strains, is first and foremost dependent on such reliable deformation capturing. This paper first presents a state-of-the-art review of existing methods for capturing deformation of concrete structures at elevated temperatures. Key merits, limitations and challenges associated with each measuring technique are discussed. It is shown that existing testing facilities and measuring instruments generally do not allow reliable direct measurement of deformation and strain of high-temperature concrete. As a result, the deformation has typically been captured either indirectly or outside the heated zones, inevitably introducing additional uncertainty and errors that are difficult to be adequately quantified. On the basis of that review, the paper details a new test set-up for reliable non-contact full-field deformation capturing of concrete structures at high temperatures using 3D Digital Image Correlation technique. Key features of the new setup that enable to successfully address major challenges of thermal boundary condition, thermal stability of speckle pattern, contrast of image and hot air movement are presented; together with evidences giving confidence to the reliability of such set-up. With its combined advantages of reliable full-field deformation capturing and thermal boundary conditions on test specimens, the new set-up allows to generate required reliable data on performance of concrete at elevated temperatures, thereby facilitating the development of effective rational fire design and analysis of concrete structures

Application of digital image correlation system for reliable deformation measurement of concrete structures at high temperatures

Reliable data on concrete deformation at high temperatures are critical to ensure the suitable predictive capability of the models for such important deformation-related properties as stress-strain relations, modulus of elasticity and load-induced thermal strains. This paper first reviews currently available technologies for measuring the deformation of concrete at high temperatures and the relevant major experiments. It is shown that such deformation has usually been determined either indirectly or outside the heated zones, thereby resulting in uncertainties that are difficult to be properly quantified. Key details of a newly-developed test setup using an optimised 3D digital image correlation technique, a radiant heating facility and an optical system with a blue illumination and a band-pass filter are then reported. It is shown via both theoretical and experimental evidence that the new system allows to successfully overcome the challenges related to thermal radiation, contrast of image, stability of speckle pattern and presence of hot air; thereby proving the reliability and capability of this innovative setup. Finally, several key potential applications of the new system are suggested

Far Upstream Binding Protein 1 (FUBP1) participates in translational regulation of Nrf2 protein under oxidative stress

Oxidative stress is ubiquitously involved in disease etiology or progression. While the damaging effects have been well characterized, how cells deal with oxidative stress for prevention or removal of damage remains to be fully elucidated. Works from our laboratory have revealed de novo Nrf2 protein translation when cells are encountering low to mild levels of oxidative stress. Nrf2 encodes a transcription factor controlling a myriad of genes important for antioxidation, detoxification, wound repair and tissue remodeling. Here we report a role of FUBP1 in regulating de novo Nrf2 protein translation. An increase of FUBP1 binding to Nrf2 5′UTR due to H2O2 treatment has been found by LC-MS/MS, Far Western blot and ribonucleoprotein immunoprecipitation assays. Blocking FUBP1 expression using siRNA abolished H2O2 from inducing Nrf2 protein elevation or Nrf2 5′UTR activity. While no nuclear to cytoplasmic translocation was detected, cytosolic redistribution to the ribosomal fractions was observed due to oxidant treatment. The presence of FUBP1 in 40/43S ribosomal fractions confirm its involvement in translation initiation of Nrf2 protein. When tested by co-immunoprecipitation with eIF4E, eIF2a, eIF3η and eIF1, only eIF3η was found to gain physical interaction with FUBP1 due to H2O2 treatment. Our data support a role of FUBP1 for promoting the attachment of 40S ribosomal subunit to Nrf2 mRNA and formation of 43S pre-initiation complex for translation initiation of Nrf2 protein under oxidative stress. © 2021Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]