Search for: All records

Environmentally benign, highly stable oxides exhibiting desirable optical properties and high near-IR reflectance are being researched for their potential application as pigments. Mg1−xMxV2O6 (M = Mn, Cu, Co, or Ni) oxides with brannerite-type structures were synthesized by the conventional solid-state reaction method to study their optical properties. These series exhibit structural transitions from brannerite (C2/m) to distorted brannerite (P1¯) and NiV2O6-type (P1¯) structures. The average color of Mg1−xMxV2O6 compounds varies from reddish-yellow to brown to dark brown. The L*a*b* color coordinates reveal that Mg1−xCuxV2O6 and Mg1−xNixV2O6 show more red hues in color with x = 0.4 and x = 0.5, respectively. The UV–Vis diffuse reflectance spectra indicate a possible origin for these results include the ligand-to-metal charge transfer (O2− 2p-V5+ 3d), metal-to-metal charge transfer (from Mn2+ 3d/Cu2+ 3d/Co2+ 3d/Ni2+ 3d to V5+ 3d), band gap transitions, and d–d transitions. Magnetic property measurements revealed antiferromagnetic behavior for the compounds Mg1−xMxV2O6 (M = Mn, Cu, Co, and Ni), and an oxidation state of +2 for the M ions was deduced from their Curie–Weiss behavior. The system Mg1−xMnxV2O6 has a NIR reflectance in the range between 40% and 70%, indicating its potential to be utilized in the pigment industry. 

Integrated sensing and communication (ISAC) systems traditionally presuppose that sensing and communication (S&C) channels remain approximately constant during their coherence time. However, a “DISCO” reconfigurable intelligent surface (DRIS), i.e., an illegitimate RIS with random, time-varying reflection properties that acts like a “disco ball,” introduces a paradigm shift that enables active channel aging more rapidly during the channel coherence time. In this letter, we investigate the impact of DISCO jamming attacks launched by a DRIS-based fully-passive jammer (FPJ) on an ISAC system. Specifically, an ISAC problem formulation and a corresponding waveform optimization are presented in which the ISAC waveform design considers the trade-off between the S&C performance and is formulated as a Pareto optimization problem. Moreover, a theoretical analysis is conducted to quantify the impact of DISCO jamming attacks. Numerical results are presented to evaluate the S&C performance under DISCO jamming attacks and to validate the derived theoretical analysis. 

Abstract This study presents an experimental investigation to examine the mixed‐mode fracture behavior of fused filament fabrication printed acrylonitrile butadiene styrene (ABS). The single‐edge notch bending specimen configuration is employed to perform mixed‐mode fracture experiments. Four distinct printing orientations—90°, 0°, 45°/−45°, and 90°—are investigated. For each orientation, fracture studies are conducted under pure mode‐I loading (symmetric three‐point bending), mixed‐mode I/II, and pure mode‐II loading (asymmetric three‐point bending) to establish a mixed‐mode fracture criterion. The study evaluates the influence of printing orientation on fracture toughness, crack propagation behavior, and the mixed‐mode fracture criterion. Scanning electron microscopy (SEM) is utilized to analyze the fracture surfaces and correlate the observed fracture mechanisms with the measured fracture toughness values. The findings reveal that printing orientation significantly affects both the fracture toughness and the mixed‐mode fracture criterion. Among the orientations studied, the 90° specimens exhibit the highest fracture toughness and superior performance under all mixed‐mode conditions. SEM images of the fracture surfaces across different printing orientations show the formation of smooth shear zones of varying sizes near the crack tip under mixed‐mode and pure mode‐II conditions. These zones suggest an enhanced resistance to crack propagation, with the degree of improvement differing among the orientations. HighlightsMixed‐mode fracture behavior of 3D‐printed acrylonitrile butadiene styrene.Printing orientations have a major influence on mixed‐mode fracture criterion.90° printing orientation has the highest fracture toughness for mode‐mixities.0° printing orientation has the lowest fracture toughness for mode‐mixities.Fracture surface has dominant shear zone for all mode‐mixities except mode‐I.