Science
Physics and the wider sciences — research, discoveries and the ideas behind them.
Physics-Informed Neural Networks as Fast Surrogate Models for Electrochemical Flow Reactors
This paper introduces a physics-informed neural network (PINN) to model a transient two-dimensional electrochemical flow reactor, trained without labeled concentration data by embedding governing equations and conditions into a loss function. The PINN accurately predicts concentration fields across a broad operating domain, showing strong agreement with finite-difference solutions and achieving a 5.34 times faster inference speed. This demonstrates PINNs as accurate and efficient parametric surrogates for electrochemical transport problems, foundational for low-computational-cost digital-twin modeling.
Characterization of Thermal Systems from Noisy and Low-resolution Measurements Using Dynamic Mode Decomposition
This chapter explores the application of Dynamic Mode Decomposition (DMD) for characterizing thermal systems using noisy and low-resolution measurement data. It focuses on preprocessing and truncation strategies to improve stability and interpretability, considering cases like forced convection and transient heat conduction. The study demonstrates that DMD can effectively recover dominant thermal behavior from sparse and degraded datasets with appropriate truncation, balancing reconstruction fidelity and noise sensitivity.
Theban tomb reveals how Egyptian burial trends evolved in time
A new study on Theban tomb 209 reveals how ancient Egyptian burial practices evolved over centuries. Initially, individual burials in elaborate coffins were common, but later periods saw the reuse of existing sites, leading to increased density and the superposition of bodies. This adaptation to previous burials suggests a "funerary memory" rather than a chaotic accumulation.
Hex9: A Quasi-Authalic, Quasi-Continuous Hexagonal DGGS on the Reference Ellipsoid
Hex9 is a novel discrete global grid system (DGGS) that prioritises geometric coherence, leading to a unique hexagonal hierarchy with aperture 9 refinement. This system allows for a quasi-continuous addressing scheme that recovers points on a reference ellipsoid to arbitrary precision without relying on a prior coordinate reference system. Its design is projection- and ellipsoid-independent, with a separable geometric realisation that achieves quasi-uniform cell areas on WGS84.
Comment on "Quantum mechanics based on real numbers: a consistent description"
This comment on a recent arXiv paper argues that a novel idea using flag states to transform complex state vectors and operators to real ones effectively leads to a quantum mechanics that is complex in disguise. The comment also asserts that the claim that real-valued quantum mechanics cannot be falsified is conceptually flawed.
Coupling model of metallic target ablation-plasma evolution-radiation under nanosecond laser irradiation
A multi-physics coupling model has been developed for pure iron under nanosecond laser irradiation, integrating laser energy deposition, phase transitions, plasma expansion, and spectral radiation. The model successfully simulates plasma shielding, supersonic expansion of ablation products, and the complete evolution of the plasma plume. Comparisons with experimental data and other spectral programs validate the model's accuracy in describing plasma inhomogeneity and radiation transport.
Quantum nature of gravity and spacetime: Fundamental insights from the Hoyle-Narlikar theory
The Hoyle-Narlikar theory of gravity, an action-at-a-distance formulation, is highlighted for its mathematical rigor and incorporation of Mach's principle. It proposes that two-point functions are more fundamental than the metric in determining spacetime structure. This theory offers insights into quantum spacetime, suggesting a non-local description where the universe informs local causal structure at the Planck scale.
Wildfire forces evacuation of NASA's Deep Space Network complex in Spain
A fast-moving wildfire in Spain forced the evacuation and temporary suspension of operations at NASA's Madrid Deep Space Communications Complex. This facility is a crucial part of NASA's Deep Space Network, supporting over 40 missions from the Moon to the Solar System's edge. NASA has transitioned mission support to its California complex to ensure uninterrupted service.
Halo structure and lensing signatures of a polytropic dark matter fluid
This research explores how a minimal effective pressure in dark matter can alter nonlinear halo structure while maintaining the successful large-scale predictions of the Lambda cold dark matter (CDM) model. By considering a barotropic relation, the study finds that dark matter develops a finite effective sound speed inside collapsed halos, leading to density profiles with quadratic central flattening. The model predicts a moderate suppression of central lensing amplitude compared to Navarro-Frenk-White halos, with modifications to the convergence power spectrum only at high multipoles.