Cracks develop various surface patterns as they propagate in three-dimensional (3D) materials. Symmetry-breaking topological defects in nominally tensile (mode-I) fracture emerge in the slow (noninertial) regime, taking the form of surface steps. We show that the same phase-field framework that recently shed basic light on dynamic (inertial) tensile fracture in three dimensions, also gives rise to crack surface steps. Step formation is shown to involve two essential physical ingredients: finite-strength quenched disorder and a small, mesoscopic antiplane shear (mode-III) loading component (on top of the dominant tensile, mode-I loading component). We quantify the nonlinear interplay between disorder (both its strength and spatial correlation length) and mesoscopic mode I+III mixity in controlling step formation. Finally, we show that surface steps grow out of the small-scale, background surface roughness and are composed of two overlapping crack segments connected by a bridging crack, in agreement with experiments.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevLett.133.226102 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Antifouling Copper Surfaces Interfere with Wet Chemical Nitrate Sensors: Characterization and Mechanistic Investigation.
ACS ES T Water
January 2025
Mechanical Engineering, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, SO17 1BJ, United Kingdom.
Wet chemical sensors autonomously sample and analyze water using chemical assays. Their internal fluidics are not susceptible to biofouling (the undesirable accumulation of microorganisms, algae, and animals in natural waters) due to the harsh chemical environment and dark conditions; however, the sample intake and filter are potentially susceptible. This paper describes the use of copper intake filters, incorporated to prevent fouling, on two different wet chemical nitrate sensors that each use different variants of the Griess assay (in particular, different nitrate reduction steps) to quantify nitrate concentrations.
View Article and Find Full Text PDFInfluence of zinc oxide nanoparticles on the carbon accumulation on silver exposed to carbon dioxide hydrogenation reaction conditions.
Nanoscale
January 2025
Center for Energy and Environmental Sciences, Paul Scherrer Institute, Forschungsstrasse 111, 5232, Villigen, Switzerland.
The strong influence of surface adsorbates on the morphology of a catalyst is exemplified by studying a silver surface with and without deposited zinc oxide nanoparticles upon exposure to reaction gases used for carbon dioxide hydrogenation. Ambient pressure X-ray photoelectron spectroscopy and scanning tunneling microscopy measurements indicate accumulation of carbon deposits on the catalyst surface at 200 °C. While oxygen-free carbon species observed on pure silver show a strong interaction and decorate the atomic steps on the catalyst surface, this decoration is not observed for the oxygen-containing species observed on the silver surface with additional zinc oxide nanoparticles.
View Article and Find Full Text PDFConventional laser micromachining technologies rely on trial-and-error optimization to obtain precise surface geometry. In this study, we present a laser micromachining setup that enables the preparation of the desired surface geometry without the need for parameter exploration. The setup consists of a laser scanning system, a coaxial imaging system, a paraxial laser line projector, and a three-axis stage.
View Article and Find Full Text PDFExploring the Activation of Atomically Precise [Pt(CO)(PPh)] Clusters: Mechanism and Energetics in Gas Phase and on an Inert Surface.
ACS Nano
January 2025
Institute of Physical Chemistry, Karlsruhe Institute of Technology, Kaiserstraße 12, Karlsruhe 76131, Germany.
Atomically precise clusters such as [Pt(CO)(PPh)] ( = 1,2) (PPh is triphenylphosphine) are known as precursors for making oxidation catalysts. However, the changes occurring to the cluster upon thermal activation during the formation of the active catalyst are poorly understood. We have used a combination of hybrid mass spectrometry and surface science to map the thermal decomposition of [Pt(CO)(PPh)](NO).
View Article and Find Full Text PDFEnhanced Nitrous Oxide Decomposition on Zirconium-Supported Rhodium Catalysts by Iridium Augmentation.
Environ Sci Technol
January 2025
Institute for Catalysis, Hokkaido University, N-21, W-10, Sapporo 001-0021, Japan.
The effective elimination of NO from automobile exhaust at low temperatures poses significant challenges. Compared to other materials, supported RhO catalysts exhibit high NO decomposition activities, even in the presence of O, CO, and HO. Metal additives can enhance the low-temperature NO decomposition activities over supported RhO catalysts; however, the enhancement mechanism and active sites require further investigation.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!