A model is presented which uses the Vickers microindentation hardness of ductile crystals such as sodium chloride to predict the uniaxial compaction behavior of compacts. A general approach first developed in the materials science field to predict the densification of particulate matter under hydrostatic loading was followed. However, modifications to account for the effects of particle geometry and the closed-die loading conditions were considered. Using the standard microindentation hardness value of sodium chloride, the model predicted the densification behavior of this material at a punch displacement rate of 1 mm/min. Densification at higher compaction rates was predicted by considering the effect of deformation kinetics on the hardness. Secondary factors which affect compaction, such as particle size effects and die-wall friction, are also briefly discussed.
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http://dx.doi.org/10.1002/jps.2600790214 | DOI Listing |
Materials (Basel)
December 2024
Department of Building Construction, Technical Upper School of Architecture, University of Granada, Campo del Principe, E18071 Granada, Spain.
Modern construction is largely dependent on steel and concrete, with natural materials such as earth being significantly underutilised. Despite its sustainability and accessibility, earth is not being used to its full potential in developed countries. This study explores innovative building materials using Alhambra Formation soil (Granada, Spain) reinforced with difficult-to-recycle agricultural waste: polypropylene fibres contaminated with organic matter and leachates.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Institute of Physical Chemistry, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen 52074, Germany.
The adsorption of ellipsoidal colloidal particles on liquid interfaces induces interfacial deformation, resulting in anisotropic interface-mediated interactions and the formation of superstructures. Soft prolate-shaped microgels at the air-water interface offer an ideal model for studying spontaneous capillary-driven self-assembly due to their tunable aspect ratio, controlled functionality, and softness. These microgels consist of a polystyrene core surrounded by a cross-linked, fluorescently labeled poly([Formula: see text]-isopropylmethylacrylamide) shell.
View Article and Find Full Text PDFPLoS One
December 2024
School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an, China.
Understanding he impact of dry-wet and freeze-thaw cycles on the mechanical properties of unloaded damaged rock masses in reservoir bank slopes is crucial for revealing the deformation and failure mechanisms in artificially excavated slope rock masses within fluctuation zones. To address, the study focuses on unloaded damaged samples subjected to excavation disturbances, conducting various cycles of dry-wet and freeze-thaw treatment along with uniaxial and triaxial re-loading tests. A damage statistical constitutive model was established based on the experimental results and validated using numerical simulation methods.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Laboratory of Structure of Polymer Materials, Enikolopov Institute of Synthetic Polymer Materials Russian Academy of Sciences (ISPM RAS), Profsoyuznaya St. 70, 117393 Moscow, Russia.
The stages of solid-state processing of nanocomposites, based on nascent disentangled ultra-high-molecular-weight polyethylene (d-UHMWPE) reactor powders (RPs) and carbon nanoparticles (NPs) of various types, were meticulously investigated. The potential for optimizing the filler distribution through variation of the processing parameters, and the impact of the d-UHMWPE RP and nanofiller type on the electrical conductivity of the resulting composites were discussed. The specifics of the dependences of conductivity and tensile strength on the deformation ratio for the composites, oriented under homogeneous shear conditions, were investigated.
View Article and Find Full Text PDFLangmuir
December 2024
Department of Chemistry and Physics of Materials, Paris-Lodron University Salzburg, Jakob-Haringer-Straße 2a, A-5020 Salzburg, Austria.
Chemical transformations at metal oxide interfaces that are triggered by mechanical energy set the basis for applications in the fields of tribo- and mechanochemistry, ceramic and composite processing, and piezoelectric devices. We investigated the early stages of tribochemically initiated radical chemistry of structurally well-defined TiO and BaTiO nanoparticles in argon or in oxygen atmosphere. Electron paramagnetic resonance spectroscopy enabled the determination of the chemical nature and concentration of paramagnetic surface species which form upon uniaxial powder compaction at room temperature.
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