The second-order generalized integrator (SOGI), which can be used to attenuate the self-interference of the fundamental tone, is unable to fully reject DC offsets on the input signal. Consequently, the performance of any SOGI based synchrophasor estimation (SE) technique might be compromised in the presence of such DC components. The current work presents a SE algorithm which adopts an enhanced SOGI formulation, robust against DC, combined with a three-point IpDFT and a three nominal fundamental period Hanning observation window. Its simultaneous compliance with both phasor measurement unit (PMU) P and M performance classes is assessed by means of a simulated environment where all the operating conditions defined by the IEC/IEEE 60255-118-1:2018 standard are evaluated combined with a 10% static DC offset and under two different noise levels. Furthermore, the method adopts a dedicated mechanism for the detection of low amplitude 2nd harmonic tones and the correction of their impacts under off-nominal frequency conditions. Finally, its resilience against multiple simultaneous harmonic interferences is also analyzed together with its performance in the presence of decaying DC components.
Citrus processing generates large quantities of agro-industrial residues that pose environmental challenges but also offer valuable opportunities for sustainable valorization. Among them, orange peel waste (OPW), one of the most abundant citrus by-products, is rich in pectin, polyphenols, flavonoids, carotenoids, and essential oils, particularly d-limonene. Growing interest in circular and bio-based economy strategies has driven research on recovering these bioactive compounds. This review provides a comprehensive overview of sustainable OPW valorization. It first discusses the chemical composition of OPW and its importance for downstream processing, then critically evaluates conventional and green extraction technologies, including enzyme-, ultrasound-, microwave-assisted, deep eutectic solvent (DES), and supercritical CO₂ extraction, considering efficiency, scalability, and environmental performance. Integrated biorefinery approaches aimed at maximizing resource utilization and minimizing waste are also examined. OPW is highlighted as a versatile renewable feedstock for producing high-value compounds and bio-based materials. Advances in green extraction and hybrid bioprocessing have improved recovery while reducing solvent use and environmental impact. Citrus-derived compounds show broad applications in functional foods, nutraceuticals, biodegradable materials, environmental remediation, and emerging nanomaterials. Unlike previous reviews, this work integrates extraction technologies, environmental applications, and citrus-derived nanotechnology within a unified framework supporting circular bioeconomy, waste reduction, and sustainable resource management.
Automated inspection systems are increasingly deployed in railway maintenance to reduce workshop-based inspection workload and to support availability-driven planning. Yet, there is limited guidance on how to derive verifiable reliability requirements that are explicitly conditioned by the operational and economic consequences of workshop fallback when automation is unavailable. This paper proposes a consequence-conditioned requirement-derivation framework that (i) models inspection-system availability bottom-up from a modular decomposition, (ii) quantifies fallback-induced functional loss through additional workshop workload, and (iii) formulates an economic admissibility constraint that yields a maximum admissible failure-rate threshold (equivalently, a minimum mean time between failures (MTBF)) consistent with predefined operational-economic targets. The structural properties of this admissibility constraint (feasibility and monotonicity) are analytically characterised to support transparent robustness assessment. The admissible threshold is then operationalised via back-propagation, cast as constrained lifetime-tuning to produce auditable element-level procurement targets under alternative allocation policies. The framework is demonstrated through an industrial automated underframe inspection system, showing how an MTBF requirement for a selected inspection subsystem can be derived from a break-even condition between annual benefit and expected fallback cost, and how required lifetime improvements depend on the allocation policy. The approach positions reliability modelling as a decision-support mechanism for validating the operational and economic viability of automated maintenance-inspection architectures.
The existence of an exponential attractor for a dissipative dynamical system generated by a reaction-diffusion problem with nonlocal viscous effects and non-autonomous forces is proved. In this non-autonomous setting the approach of pullback exponential attractor is used, despite of the obstacles concerning regularity due to the appearance of nonlocal terms. (c) 2026 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
A novel cBN–hardened B12(C,Si,B)3–SiC composite was successfully fabricated by reactive spark plasma sintering (SPS), and its unlubricated sliding wear performance was evaluated. Powder mixtures with varying B4C:Si:cBN ratios (vol%) were consolidated under different SPS conditions, and the resulting materials were characterised microstructurally and mechanically to identify suitable processing conditions for obtaining a dense (>98%) fine-grained (<1 μm) cBN–hardened (∼33.4 GPa) B12(C,Si,B)3–SiC composite—namely, 72B4C:18Si:10cBN (vol%) SPSed at 1500 °C, with a heating rate of 200 °C/min, a dwell time of 15 min, and an applied pressure of 75 MPa. This novel composite was then tested tribologically against diamond at a 40 N load under unlubricated sliding conditions, demonstrating a threefold improvement in wear resistance (∼(2.7 ± 0.3)·107 (N·m)/mm3) relative to that of its cBN–free reference counterpart—with very mild abrasion and no evidence of plastic grooving or grain pull-out. This enhanced performance results from the cBN third phase increasing the overall hardness of the composite and promoting the formation of a more protective and lubricating oxide tribolayer. Incorporating cBN into ceramic microstructures could thus be an effective strategy to enhance hardness and tribological performance, provided that sintering conditions are sufficiently mild to prevent its transformation into hBN.
