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Development of damage mechanisms of carbon fibre-reinforced polymer using acoustic emission: effect of plasma surface treatment
No full textThis study investigates the effect of atmospheric pressure air plasma (APA) treatment on the mechanical performance, damage mechanisms and damage propagation of carbon fiber (CF)/Epoxy composites by utilizing Acoustic emission (AE) method. CF fabrics are treated with APA prior to manufacturing of composites through vacuum-assisted resin infusion (VARI) process. Manufactured composites are tested for mode-I and mode-II fracture toughness tests in accordance with EN 6033, and EN6034standards,respectively. APA treatment resulted in improvements of GIC and GIIC values up to 32% and 40% over non-treated specimen. AE analysis revealed four discrete clusters representing different damage modes such as matrix cracking, interlaminar damages, fiber pull-out, and fiber breakage. The findings of the study indicate that APA treatment enhances the mechanical performance and alters the damage mechanism and propagation
Higher social class is associated with higher contextualized emotion recognition accuracy across cultures
No full textWe tested links between social status and emotion recognition accuracy (ERA) with participants from a diverse array of cultures and a new model and method of ERA, the Assessment of Contextualized Emotion (ACE), which incorporates social context and is linked to different types of social interaction across cultures. Participants from the Czech Republic (Study 1) and from 12 cultural groups in Europe, North America, and Asia (Study 2) completed a short version of the ACE, a self-construal scale, and the MacArthur Subjective Social Status (SSS) scale. In both studies, higher SSS was associated with more accuracy. In Study 2, this relationship was mediated by higher independent self-construal and moderated by countries' long-term orientation and relational mobility. The findings suggest that the positive association between higher social class and emotion recognition accuracy is due to the use of agentic modes of socio-cognitive reasoning by higher status individuals. This raises new questions regarding the socio-cultural ecologies that afford this relationship
Investigating the recursive short x-ray burst behavior of magnetars through crustal interactions
No full textEnergetic bursts from strongly magnetized neutron stars, known as magnetars, are typically detected in clusters. Once an active episode begins, anywhere from a few to thousands of hard X-ray bursts can occur over durations ranging from days to months. The temporal clustering of these recurrent bursts during an active episode suggests an underlying mechanism that triggers multiple bursts in rapid succession. These burst clusters are likely crucial for understanding the processes driving magnetar activity. In this study, we investigate the repetitive short X-ray burst behavior of magnetars through crustal interactions, employing the cellular automaton model for the magnetar crust proposed by S. K. Lander. Our simulations, based on physically motivated criteria, successfully reproduce burst clustering. Additionally, the durations and energetics of active episodes in our simulations agree well with observational data. We discuss the potential physical mechanisms underlying burst clusters observed in numerous magnetars, as well as the reactivations of an individual magnetar
Correction to: N-doped carbon nanospheres as selective fluorescent probes for mercury detection in contaminated aqueous media: chemistry, fluorescence probing, cell line patterning, and liver tissue interaction (Environmental Science and Pollution Research, (2023), 30, 14, (40327-40339), 10.1007/s11356-022-25068-0)
No full textIt has come to our attention that the ethical approval codes for the biological and biomedical experiments conducted in this study were inadvertently omitted from the published manuscript. We would like to rectify this oversight by including the following ethical codes: IR.SBMU.RETECH.REC.1400.652 IR.SBMU.RETECH.REC.1400.907 These ethical approvals were obtained in accordance with institutional and national guidelines to ensure the ethical conduct of research. We apologize for this omission and appreciate the opportunity to clarify this important aspect of our study
Multiply perturbed response to disclose allosteric control of conformational change: application to fluorescent biosensor design
No full textProteins exhibit remarkable conformational flexibility, enabling precise functional regulation through allostery. A key application of allostery is in the design of protein-based sensors, which detect environmental changes—such as ligand binding or post-translational modifications—and convert these cues into measurable signals (e.g., fluorescence). Here, we investigate a series of ligand-binding proteins that serve as sensing domains in direct-response fluorescent biosensors, wherein ligand binding enhances fluorescence output. We employ a multiple force application approach which we term Multiply Perturbed Response (MPR) to identify “hot spot” residues that drive the conformational transition from an apo (inactive/OFF) to a holo (active/ON) state. We first present two efficient computational approaches to determine residues and forces that maximize the overlap of the observed conformational change. We then determine the overlap maximizer residues for up to five force insertion locations, and we compare them with actual insertion sites used in existing biosensors. Our analysis shows that the allosteric residues identified by MPR coincide with the fluorescent-protein insertion sites that were mapped experimentally through extensive trial-and-error. This work enhances the utility of linear response theory-based methods in uncovering multiple functionally significant regions that trigger a known conformational change. While the validity of the harmonic approximation in anharmonic conformational transitions needs additional validation, MPR gives a good starting point to explore allosteric sites. The approach might prove useful not only in the design of biosensors, but may also find applications in offering physics-based collective variables in mapping conformational transition pathways of proteins
Directional factor as the key factor for chatter free robotic milling of light alloys
No full textRobotic milling systems are increasingly used for light alloys and composites, but face challenges due to high dynamic flexibility of robots. A key issue is low-frequency chatter, linked to the robot's structural modes during high-speed operations. Therefore, this study deals with a dominant flexible mode with high tooth-passing frequencies, highlighting the influence of the directional factor. Negative directional factors can cause low-frequency chatter at high spindle speeds. Polar stability lobes show that optimal feed direction and radial engagement zones align with positive directional factors. The study shows that slotting operations assure a chatter free machining. Experimental validation confirms theoretical findings
An accurate shape sensing methodology for laminated composite wing spars based on the nonlinear deformation theory
No full textReal-time monitoring of nonlinear deformation in laminated composite tubular beams presents a critical challenge, particularly in high-aspect-ratio wing spar applications, where the existing shape sensing techniques often fail to achieve adequate accuracy. To solve this problem, this paper introduces a novel nonlinear shape sensing methodology for laminated composite tubular beams leveraging discrete strain measurements. The approach is rooted in von Karman nonlinear deformation theory and the nonlinear strain field formulations and governing differential equations are derived for employing in inverse finite element method (iFEM). The calculation method of transformed elastic constants is presented based, and the constitutive equations guide the determination of section strain orders and displacement functions. Discrete strain measurements are then employed to estimate section strain functions accurately. A deformation monitoring model on iFEM method is established and solved iteratively using the Newton-Raphson algorithm. Validation tests is performed on a laminated composite beams representing aerospace structures. Numerical and experimental results highlight a 30 % improvement in displacement prediction compared to the traditional iFEM method, which demonstrated the robustness and precision of the proposed approach. Hence, the proposed iFEM methodology offers a reliable and efficient tool for shape sensing and structural health monitoring as well as safety assurance in marine, offshore and aerospace industries
A complete circuit model for terahertz spoof surface plasmon polariton waveguides for ultrafast and accurate synthesis of terahertz integrated circuits
No full textThe increasing demand for ultra-wideband wireless communications has pushed requirements of integrated circuits (ICs) to terahertz band. Operation in the terahertz band requires ultra-high efficiency for all the building blocks in ICs; however, the conventional passive components prevent achieving desired output power levels. Moreover, these components also strongly impede the synthesis of ICs as the design flow requires an enormous number of full-wave analyses. In this paper, we present the first-ever, complete, closed form, theoretical model for Terahertz Spoof Surface Plasmon Polariton Waveguides (THz-SSPP WGs), which hold the record for the lowest loss performance among all the planar waveguides at 0.3 THz. The electromagnetic field distribution around the THz-SSPP WG is non-uniform that even makes the solution of the problem of a nonlinear differential equation of multiple variables even more challenging. Because the guided-wavenumber is non-linear because of the dispersive behavior of the waveguide and the field distribution, hence the boundary conditions depend on all the corrugation dimensions, substrate thickness, and material properties. The proposed model is the first complete closed-form model not only among all THz-SSPP WGs, but also any single conductor planar waveguide. The proposed model illustrates the behavior of the confined and propagated electromagnetic wave around the THz-SSPP WGs, where the field distribution pattern changes as any of the waveguide parameter changes in contrast with any conventional waveguide with a ground
Impact of controlled oxidation and incorporation of high entropy rare-earth alloys (HE-REAs) on the structural, physical, optical, and radiation shielding performance of zinc-borate glasses
No full textThis study investigates the influence of high entropy oxide (HEO) and high entropy alloy oxide (HEAO) dopants on the structural, optical, and radiation shielding properties of zinc-borate glasses. Two synthesis routes were employed through direct mechanical alloying of five rare-earth oxides such as Sm2O3, Ho2O3, Er2O3, Yb2O3, Gd2O3 to form (SmHoErYbGd)2O3 HEO, and mechanical alloying of the corresponding rare-earth metals followed by oxidation to produce HEAO of the same elemental composition. The central hypothesis proposed that the dopant structure and oxygen coordination, not just elemental presence, critically influence the on characteristic behaviors in terms of radiation attenuation. Structural analyses confirmed that HEAO-doped glasses exhibit more homogeneous, amorphous networks. Optical characterizations revealed red-shifted absorption edges and lower Urbach energies in HEAO samples, indicating reduced disorder. HEAO-doped glasses showed superior gamma-ray shielding, with higher linear attenuation coefficients and lower half-value layers than HEO or undoped samples. Most notably, HEAO glass achieved the highest fast neutron removal cross-section, surpassing water, graphite, and B4C. These findings demonstrate that rare-earth high entropy alloy oxides offer a structurally optimized pathway for designing next-generation multifunctional glasses for radiation-related applications
Effect of h-BN and aluminosilicate filler configuration and distribution on thermal conductivity and structural integrity of hybrid PEEK composites
No full textAchieving high through-plane thermal conductivity (TC) and mechanical strength in PEEK-based composites at high filler loadings is limited by processing challenges, poor filler-matrix interfaces, and filler aggregation. This work addresses these issues by using a hybrid filler approach using hexagonal boron nitride (hBN) and aluminosilicate (AlS) fillers in a PEEK matrix via an optimized twin-screw co-extrusion. During processing, controlled melt flow facilitated the polymer-assisted filler separation, preserving hBN's platelet form and enabling a synergistic hybrid effect at a combined 60 wt% loading. Results show that composites with higher hBN content exhibited greatly enhanced TC, with the 50 wt% hBN/10 wt% AlS formulation achieving 7.992 W/(m K) in-plane and 1.785 W/(m K) through-plane, 3059% and 738% improvements over neat PEEK. Those with higher AlS content demonstrated improved mechanical properties, with 10 wt% hBN/50 wt% AlS composite reaching tensile strength of 96.31 MPa, matching neat PEEK and outperforming single filler hBN/PEEK by 44%. Rheological studies revealed shear-thinning behavior of hybrid composites, with melt viscosity tunable by adjusting filler ratios. The composites also maintained excellent thermal stability under typical operating temperatures (≤ 250°C). Thus, current work presents a scalable co-extrusion process for developing robust, thermally conductive hybrid PEEK composites by addressing the critical challenge of co-optimizing thermal conductivity and mechanical strength, positioning these materials as strong candidates for high-performance thermal management applications