We study a calcium aluminosilicate glass of composition (SiO(2))(0.67)-(Al(2)O(3))(0.12)-(CaO)(0.21) by means of molecular-dynamics simulations, using a potential made of two-body and three-body interactions. In order to prepare small samples that can subsequently be studied by first principles, the finite size effects on the liquid dynamics and on the glass structural properties are investigated. We find that finite size effects affect the Si-O-Si and Si-O-Al angular distributions, the first peaks of the Si-O, Al-O, and Ca-O pair correlation functions, the Ca coordination, and the oxygen atoms' environment in the smallest system (100 atoms). We give evidence that these finite size effects can be directly attributed to the use of three-body interactions.
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http://dx.doi.org/10.1063/1.1724815 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Faculty of Technical Chemistry, Institute of Chemical Technologies and Analytics, Technische Universität Wien, Vienna 1060, Austria.
Atomic force microscopy-infrared spectroscopy (AFM-IR) is a photothermal scanning probe technique that combines nanoscale spatial resolution with the chemical analysis capability of mid-infrared spectroscopy. Using this hybrid technique, chemical identification down to the single molecule level has been demonstrated. However, the mechanism at the heart of AFM-IR, the transduction of local photothermal heating to cantilever deflection, is still not fully understood.
View Article and Find Full Text PDFJ Anat
January 2025
Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences (ILCaMS) and Human Anatomy Resource Centre (HARC), Education Directorate, University of Liverpool, Liverpool, UK.
The importance of interactions between neighbouring rapidly growing tissues of the head during development is recognised, yet this competition for space remains incompletely understood. The developing structures likely interact through a variety of mechanisms, including directly genetically programmed growth, and are mediated via physiological signalling that can be triggered by structural interactions. In this study, we aimed to investigate a different but related potential mechanism, that of simple mechanical plastic deformation of neighbouring structures of the head in response to soft tissue expansion during human postnatal ontogeny.
View Article and Find Full Text PDFEntropy (Basel)
January 2025
Department of Mechanical and Aerospace Engineering, The University of Manchester, Manchester M1 3PL, UK.
This study investigates the flow field around a finite rectangular prism using both experimental and computational methods, with a particular focus on the influence of the turbulence approach adopted, the mesh resolution employed, and different subgrid length scales. Ten turbulence modelling and simulation approaches, including both 'scale-modelling' Reynolds-Averaged Navier-Stokes (RANS) models and 'scale-resolving' Delayed Detached Eddy Simulation (DDES), were tested across six different mesh resolutions. A case with sharp corners allows the location of the flow separation to be fixed, which facilitates a focus on the separated flow region and, in this instance, the three-dimensional interaction of three such regions.
View Article and Find Full Text PDFISA Trans
January 2025
School of Mathematics and Physics, Qingdao University of Science and Technology, Qingdao 266061, China; Qingdao Innovation Center of Artificial Intelligence Ocean Technology, Qingdao 266061, China; The Research Institute for Mathematics and Interdisciplinary Sciences, Qingdao University of Science and Technology, Qingdao 266061, China. Electronic address:
This paper considers the event-triggered adaptive fault-tolerant control (FTC) problem for a class of stochastic nonlinear systems suffering from finite number of actuator failures and abrupt system external failure. Unlike existing event-triggered mechanisms (ETMs), this paper proposes an improved switching threshold mechanism (STM) that effectively addresses the potential system security hazards caused by large signal impulses when both the magnitude size of the controller and its rate of change are too large, while also saving energy consumption. Especially, when the occurrence of both actuator failure and system external failure may lead to over-change rate of the controller, by using the multi-dimensional Taylor network (MTN) approximation technique, the adaptive fault-tolerant control scheme designed based on the improved STM not only has lower resource consumption, but also indirectly improves the control performance of the system by ensuring the system security operation.
View Article and Find Full Text PDFMonte Carlo Methods Appl
December 2024
Computer Languages and Systems Software Group, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
Correlation coefficients and linear regression values computed from group averages can differ from correlation coefficients and linear regression values computed using individual scores. This observation known as the ecological fallacy often assumes that all the individual scores are available from a population. In many situations, one must use a sample from the larger population.
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