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Physics-informed deep learning for one-dimensional consolidation

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 420-430页

作者： Yared W.Bekele Rock and Soil Mechanics group SINTEF ASTrondheimNorway

Neural networks with physical governing equations as constraints have recently created a new trend in machine learning *** this context,a review of related research is first presented and *** potential offered by such physics-informed deep learning models for computations in geomechanics is demonstrated by application to one-dimensional(1D)*** governing equation for 1D problems is applied as a constraint in the deep learning *** deep learning model relies on automatic differentiation for applying the governing equation as a constraint,based on the mathematical approximations established by the neural *** total loss is measured as a combination of the training loss(based on analytical and model predicted solutions)and the constraint loss(a requirement to satisfy the governing equation).Two classes of problems are considered:forward and inverse *** forward problems demonstrate the performance of a physically constrained neural network model in predicting solutions for 1D consolidation *** problems show prediction of the coefficient of ***’s problem,with varying boundary conditions,is used as a numerical example and the deep learning model shows a remarkable performance in both the forward and inverse *** the application demonstrated here is a simple 1D consolidation problem,such a deep learning model integrated with a physical law has significant implications for use in,such as,faster realtime numerical prediction for digital twins,numerical model reproducibility and constitutive model parameter optimization.

关键词： Physics-informed deep learning Consolidation Forward problems Inverse problems

Stress-augmented thermal activation:Tribology feels the force

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Friction 2018年第1期6卷 1-31页

作者： Hugh SPIKES Tribology group Department of Mechanical EngineeringImperial College

In stress-augmented thermal activation, the activation energy barrier that controls the rate of atomic and molecular processes is reduced by the application of stress, with the result that the rate of these processes increases exponentially with applied stress. This concept has particular relevance to Tribology, and since its development in the early twentieth century, it has been applied to develop important models of plastic flow, sliding friction, rheology, wear, and tribochemistry. This paper reviews the development of stress-augmented thermal activation and its application to all of these areas of Tribology. The strengths and limitations of the approach are then discussed and future directions considered. From the scientific point of view, the concept of stress-augmented thermal activation is important since it enables the development of models that describe macroscale tribological performance, such as friction coefficient or tribofilm formation, in terms of the structure and behaviour of individual atoms and molecules. This both helps us understand these processes at a fundamental level and also provides tools for the informed design of lubricants and surfaces.

关键词： stress activation stress augmented thermal activation mechanochemistry friction EHD friction wear Eyring

Susceptibility of Large Wind Power Plants to Voltage Disturbances-Recommendations to Stakeholders

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Journal of Modern Power Systems and Clean Energy 2022年第2期10卷 416-429页

作者： Roger Alves de Oliveira Math H.J.Bollen the Electric Power Engineering group Lulea University of TechnologySkellefteaSweden

Sufficient fault ride-through(FRT)of large wind power plants(WPPs)is essential for the operation security of transmission *** majority of studies on FRT do not include all disturbances originating in the transmission system or the disturbances irrelevant to the operation *** on the knowledge of power quality,this paper provides a guide to stakeholders in different aspects of FRT for wind turbines(WTs)and *** paper details the characteristics of the most common disturbances originated in the transmission system,how they propagate to the WT terminals,and how they impact the dynamic behavior of a large *** paper shows that the details of the voltage disturbances,not only in the transmission system,but also at the WT terminals,should be taken into ***,a detailed representation or characterization of voltage dips is important for FRT studies,despite that the simplified models used in the literature are *** paper strongly recommends that distinct events and additional characteristics such as the phase-angle jump and oscillations in the transition segments should be considered in FRT analysis.

关键词： Wind power generation wind farm power quality fault ride-through(FRT) low voltage ride-through(LVRT)

Terminal Effect of Drop Coalescence on Single Drop Mass Transfer Measurements and Its Minimization

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Chinese Journal of Chemical Engineering 2001年第2期9卷 204-207页

作者：李天文毛在砂陈家镛费维扬 TechnicalCenterofLTHNaturalGasChemical（group）Co. Luzhou646300China

For the mass transfer to single drops during the stage of steady buoyancy-driven motion, experimental measurement is complicated with the terminal effect of additional mass transfer during drop formation and coalescence at the drop collector. Analysis reveals that consistent operating conditions and experimental procedure are of critical significance for minimizing the terminal effect of drop coalescence on the accuracy of mass transfer measurements. The novel design of a totally-closed extraction column is proposed for this purpose, which guarantees that the volumetric rate of drop phase injection is exactly equal to that of withdrawal of drops. Tests in two extraction systems demonstrate that the experimental repeatability is improved greatly and the terminal effect of mass transfer during drop coalescence is brought well under control.

关键词： solvent extraction mass transfer single drop terminal effect drop coalescence

Functionalized monodisperse microbubble production:microfluidic method for fast,controlled,and automated removal of excess coating material

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Microsystems & Nanoengineering 2024年第4期10卷 391-401页

作者： M.R.P.van den Broek M.Versluis A.van den Berg T.Segers BIOS/Lab on a Chip group Max Planck Center Twente for Complex Fluid DynamicsUniversity of TwenteEnschedeThe Netherlands Physics of Fluids group University of TwenteEnschedeThe Netherlands

Functionalized monodisperse microbubbles have the potential to boost the sensitivity and efficacy of molecular ultrasound imaging and targeted drug delivery using bubbles and *** bubbles can be produced in a microfluidic flow focusing ***,their functionalization and sequential use require removal of the excess lipids from the bubble suspension to minimize the use of expensive ligands and to avoid competitive binding and blocking of the receptor *** date,excess lipid removal is performed by centrifugation,which is labor intensive and challenging to *** importantly,as we show,the increased hydrostatic pressure during centrifugation can reduce bubble ***,we introduce a novel automated microfluidic’washing’***,bubbles are injected in a microfluidic chamber 1mm in height where they are left to float against the top ***,lipid-free medium is pumped through the chamber to remove excess lipids while the bubbles remain located at the top ***,the washed bubbles are resuspended and removed from the device into a collection *** demonstrate that the present method can(i)reduce the excess lipid concentration by 4 orders of magnitude,(ii)be fully automated,and(iii)be performed in minutes while the size distribution,functionality,and acoustic response of the bubbles remain ***,the presented method is a gateway to the fully automated production of functionalized monodisperse microbubbles.

关键词： bubble fluid method

Development of spin-on-glass process for triple metal interconnects

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Journal of Semiconductors 2010年第12期31卷 143-145页

作者：彭力赵文彬王国章于宗光 No.58 Institute China Electronic Technology Group Corporation

Spin-on-glass （SOG）, an interlayer dielectric material applied in liquid form to fill narrow gaps in the sub-dielectric surface and thus conducive to planarization, is an alternative to silicon dioxide （SiO2） deposited using PECVD processes. However, its inability to adhere to metal and problems such as cracking prevent the easy application of SOG technology to provide an interlayer dielectric in multilevel metal interconnect circuits, particularly in university processing labs. This paper will show that a thin layer of CVD SiO2 and a curing temperature below the sintering temperature of the metal interconnect layer will promote adhesion, reduce gaps, and prevent cracking. Electron scanning microscope analysis has been used to demonstrate the success of the improved technique. This optimized process has been used in batches of double-poly, triple-metal CMOS wafer fabrication to date.

关键词： SOG etch-back planarization multilevel metal interconnect

Space time fractional KdV Burgers equation for dust acoustic shock waves in dusty plasma with non-thermal ions

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Chinese Physics B 2014年第7期23卷 316-322页

作者： Emad K.El-Shewy Abeer A.Mahmoud Ashraf M.Tawfik Essam M.Abulwafa Ahmed Elgarayhi Theoretical Physics group Physics DepartmentFaculty of ScienceMansoura University

The KdV-Burgers equation for dust acoustic waves in unmagnetized plasma having electrons, singly charged non- thermal ions, and hot and cold dust species is derived using the reductive perturbation method. The Boltzmann distribution is used for electrons in the presence of the cold （hot） dust viscosity coefficients. The semi-inverse method and Agrawal variational technique are applied to formulate the space-time fractional KdV-Burgers equation which is solved using the fractional sub-equation method. The effect of the fractional parameter on the behavior of the dust acoustic shock waves in the dusty plasma is investigated.

关键词： dust-acoustic waves reductive perturbation method modified Riemann-Liouville fractionalderivative space-time fractional KdV-Burgers equation

Tackling the epigenome in the pluripotent stem cells

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Journal of Genetics and Genomics 2008年第7期35卷 403-412页

作者： Chia-Lin Wei Genome Technology and Biology group Genome Institute of Singapore 138672 Singapore

Embryonic stem cells are unique in their abilities of self-renewal and to differentiate into many, if not all, cellular lineages. Transcriptional regulation, epigenetic modifications and chromatin structures are the key modulators in controlling such pluripotency nature of embryonic stem cell genomes, particularly in the developmental decisions and the maintenance of cell fates. Among them, epigenetic regulation of gene expression is mediated partly by covalent modifications of core histone proteins including methylation, phosphorylation and acetylation. Moreover, the chromatins in stem cell genome appear as a highly organized structure containing distinct functional domains. Recent rapid progress of new technologies enables us to take a global, unbiased and comprehensive view of the epigenetic modifications and chromatin structures that contribute to gene expression regulation and cell identity during diverse developmental stages. Here, we summarized the latest advances made by high throughput approaches in profiling epigenetic modifications and chromatin conformations, with an emphasis on genome-wide analysis of histone modifications and their implications in pluripotency nature of embryonic stem cells.

关键词： epigenetics histone modification ChiP-chip ChIP-PET embryonic stem cell

Bound state solutions of d-dimensional Schrdinger equation with Eckart potential plus modified deformed Hylleraas potential

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Chinese Physics B 2013年第2期22卷 80-85页

作者： Akpan N.Ikot Oladunjoye A.Awoga Akaninyene D.Antia Theoretical Physics group Department of PhysicsUniversity of UyoUyoNigeria

We study the d-dimensional Schrdinger equation for Eckart plus modified deformed Hylleraas potentials using the generalized parametric form of Nikiforov-Uvarov *** obtain energy eigenvalues and the corresponding wave function expressed in terms of a Jacobi *** also discuss two special cases of this potential comprised of the Hulthen potential and the Rosen-Morse potential in three *** results are also computed for the energy spectrum and the potentials.

关键词： parametric Nikiforov-Uvarov method new approximation scheme Eckart plus Hylleraas potential