Search Results (1,176)

Porous ceramics have shown great application potential in aerospace, electronics, and lithium-ion battery thermal management due to their low density, high specific strength, and excellent thermal insulation. Material Jetting (MJ), a high-precision 3D printing technology, enables the fabrication of porous ceramics with tailored pore structures, but the synergistic effects of pore structure parameters (configuration, porosity, and number of periods) on their thermal insulation performance remain insufficiently explored. This study systematically investigates the thermal insulation behavior of zirconia porous ceramics fabricated by MJ through experimental tests and numerical simulations. Three typical lattice configurations (Octet, Schwarz, and Gyroid) were selected, and samples with varying porosities (40%, 50%, 60%) and numbers of periods (1, 2, 3) were prepared. The results indicate that the Octet configuration (60% porosity, 3 periods) exhibits the optimal thermal insulation performance, with a minimum cold-end temperature of 58.5 °C (experiment) and 59.21 °C (simulation), attributed to its strut-based structure that forms a more tortuous heat conduction path. For the Gyroid configuration, thermal insulation performance improves with increasing porosity (reducing solid conduction dominance under non-forced convection) and decreases with decreasing number of periods (due to inhomogeneous pore distribution extending heat transfer paths). Notably, the trend of porosity affecting thermal insulation is opposite to that of compressive performance. Numerical simulation results are consistent with experimental data in both values and trends, verifying the reliability of the model. This work clarifies the key factors regulating the thermal insulation of MJ-fabricated porous ceramics and provides practical structural design guidelines for applications such as lithium-ion battery thermal runaway management. Full article

M-type hexaferrites are widely used in magnetic applications, and tailoring their properties via aliovalent substitution requires a detailed understanding of charge compensation and cation distribution. In this work, Mg²⁺/M⁴⁺ (M = Zr, Hf) co-substituted BaFe₁₂O₁₉ was synthesized via Na₂CO₃ flux and comprehensively characterized by wavelength-dispersive X-ray spectroscopy, powder and single-crystal X-ray diffraction, Rietveld refinement, X-ray absorption near-edge structure, and magnetic measurements. Increasing substitution levels x, y in BaFe_12−x−yMg_xM_yO₁₉ result in increasing lattice parameters and decreasing the room-temperature magnetic parameters saturation magnetization, remanence, and coercivity, while remanence and coercivity increase at low temperatures. Secondary phases form for nominal substitution ≥ 1. Zr⁴⁺ and Hf⁴⁺ preferentially occupy the 4f₂ site, whereas Mg²⁺ is distributed over multiple sites, as indicated by polyhedral volume analysis. Wavelength-dispersive X-ray spectroscopy confirms homogeneous elemental distribution within individual crystals but reveals significant variation in substitution levels within batches. The maximum degree of substitution for the tetravalent metals was y ≈ 1.2–1.7, with lower Mg incorporation of x ≈ 0.9–1.1. Charge compensation was found to be partially achieved via vacancy formation, while minor Fe²⁺ contributions cannot be excluded. Full article

This work reports the colloidal synthesis of Nd-containing mixed-halide perovskite quantum dots described as CsPb(Nd)Br_3−γCl_γ, followed by post-synthetic surface modification with an acid-activated amino-functional siloxane. This notation is used deliberately because the available FE-SEM, DLS, EDX, and optical data confirm the formation of an Nd-containing mixed-halide colloidal perovskite system, but do not provide direct crystallographic proof of substitutional Nd³⁺ incorporation at the Pb²⁺ B-site. The obtained dispersions show stable blue emission with a maximum at about 458 nm, a photoluminescence quantum yield of about 56%, an essentially invariant emission maximum when the excitation wavelength is varied from 300 to 390 nm, and monoexponential decay kinetics with a characteristic lifetime of 6.67 ± 0.97 ns. Field-emission scanning electron microscopy combined with morphometric analysis of at least 150 particles indicates a nanoscale size distribution with an average equivalent diameter of 8.8 nm, a median of 7.3 nm, and 93.25% of particles smaller than 25 nm. Dynamic light scattering confirms a narrow hydrodynamic size distribution in the 7–9 nm range and a low polydispersity index. Elemental mapping by EDX confirms the co-presence of Cs, Pb, Br, Cl, and Nd in the analyzed particles. The observed blue shift is discussed in terms of the combined effect of chloride incorporation, nanoscale size, possible Nd-related perturbation of the local electronic/defect structure, and reduced non-radiative losses after surface passivation. No definitive crystallographic assignment of Nd to a specific lattice site is claimed; the composition is therefore treated as nominal, and the structural interpretation remains provisional pending XRD/XPS or related studies. Full article

The ultra-short-pulse (USP) laser joining of sapphire to iron is investigated by combining electron backscatter diffraction (EBSD) and ruby (Cr³⁺) R₁ fluorescence mapping to resolve the joint microstructure and pressure distributions. Energy-dispersive X-ray spectroscopy (EDS) reveals Al, O, and Fe intermixing within the seam, consistent with the formation of thin Fe–Al–O reaction layers. R₁ fluorescence yields a maximum internal pressure of $(490\pm 80)$ MPa within the modified sapphire region and decays to near-zero within a few micrometres distance from the seam. EBSD data suggest a single-crystal sapphire lattice with localized disorientation adjacent to the joint, whereas the iron foil remains polycrystalline with rolling-induced misorientation without additional weld-induced grain refinement. These results demonstrate that USP joining of sapphire to iron produces localized interfacial reaction zones, with confined pressure predominantly occurring within sapphire. Full article

We review the structure of pseudoscalar mesons within an algebraic model formulated in the light-front framework. The approach provides a unified description of leading-twist parton distribution amplitudes, light-front wave functions, generalized parton distributions, parton distribution functions, elastic electromagnetic form factors, charge radii, and impact-parameter space distributions, all obtained from the same underlying Bethe–Salpeter wave-function representation. The analysis covers light mesons $(\pi ,K)$, the mixed $\eta$–${\eta }^{\prime }$ system, heavy–light states $(D,D_s,B,B_s,B_c)$, and heavy quarkonia $({\eta }_c,{\eta }_b)$, thereby enabling a systematic study of quark-mass effects, flavor-symmetry breaking, and the transition from emergent hadronic mass to heavy-quark dynamics. Where available, results are compared with experimental measurements, functional methods such as lattice-QCD calculations and Dyson–Schwinger Equation formalism, and other phenomenological approaches. The algebraic model thus offers a transparent, symmetry-preserving, and analytically tractable framework for connecting the longitudinal, transverse-momentum, and spatial structure of pseudoscalar mesons across all quark-mass regimes. Full article

This study introduces a novel matrix defined over the nonzero natural numbers, whose entries are governed by a rigorous closed-form expression. The matrix architecture replicates the topological properties of the Ulam spiral, mapping the integer sequence onto a structured lattice with a well-defined formulation. We investigate the interplay between the matrix’s linear algebraic properties and its number-theoretic implications. A primary focus is the established connection between the matrix’s lines, rows, diagonals, and antidiagonals, and the Hardy–Littlewood F-conjecture. By analyzing the matrix’s internal structure, this work provides a new analytical framework for further study of the conjecture. The matrix links its visual characteristics to quadratic polynomials, offering fresh insights into the distribution of prime numbers. Full article

The increasing pace of Internet of Things (IoT) and Industrial Internet of Things (IIoT) applications has exacerbated the security challenges in resource-constrained environments, where traditional cryptographic protocols incur prohibitively high computational and energy costs. These constraints are also worsened by the advent of quantum computing, which poses a long-term security risk to popular crypto-key cryptographic-based efforts. To overcome these difficulties, this paper proposes an Energy-Efficient Cryptographic Protocol Framework (EECPF) that provides mutual optimization between energy consumption, security level, and communication latency to achieve sustainable IoT security. The presented framework proposes an adaptive encryption selection mechanism that dynamically chooses cryptographic algorithms depending on device capabilities, network conditions, and threat levels derived from intrusion detection outputs. EECPF combines privacy-preserving federated learning for distributed intrusion detection with collaborative threat intelligence sharing, eliminating centralized data sharing. In addition, lattice-based post-quantum cryptography primitives are added and combined with lightweight blockchain-enforced identity management to ensure long-term authentication resilience. The models on which the framework is based are mathematically based, modeling the consumption of energy, the robustness of security, and latency, providing principled multi-objective optimization under resource constraints. The publicly available Edge-IIoTset dataset was subjected to extensive experimental assessment under realistic IIoT and IoT attack scenarios. Experiments show that EECPF can reach an intrusion detection rate of 94.7%, while reducing energy consumption by 47.3% and latency by 23.8% compared with other commonly used lightweight cryptographic methods. These were continually noticed across different heterogeneous devices and deployment environments. In general, EECPF offers an energy-aware, quantum-resilient, and scalable security solution that can be used for next-generation IoT systems, such as smart healthcare, industrial automation, and smart city infrastructures. Full article

This paper proposes a formal framework for the study of mathematical language at the intersection of fixed point theory, formal language theory, and academic discourse analysis. Mathematical texts are modeled as languages over a finite alphabet of discourse tokens, combining natural-language expressions with symbolic content. To suppress irrelevant symbolic variation, we introduce a normalization procedure in which concrete mathematical expressions are replaced by an abstract placeholder while the surrounding linguistic structure is preserved. Within this framework, we define enrichment operators on phrases and the induced operators on languages, which model admissible stylistic and structural transformations of mathematical discourse. The collection of all languages over a fixed alphabet, ordered by inclusion, is shown to form a complete lattice, allowing the application of the Knaster–Tarski fixed point theorem. As a consequence, stable linguistic configurations can be interpreted as fixed points of the induced enrichment operator. We further show that different initial languages may lead to different fixed points under the same operator, reflecting the existence of multiple stable forms of mathematical expression. In addition, we introduce a notion of lexical distance based on frequency distributions of discourse units, which provides a quantitative tool for comparing languages. The illustrative analysis suggests a saturation effect: while enrichment increases the overall distance from the initial language, the incremental changes between successive stages remain bounded, indicating a tendency towards stabilization. A concrete illustrative example based on a classical theorem from mathematical analysis demonstrates how a proof evolves through successive levels of enrichment, from a minimal linguistic core to more elaborate stylistic realizations. The proposed framework thus provides a bridge between formal language models and the linguistic structure of mathematical discourse, offering a new perspective on the organization, stability, and variation of mathematical language. Full article

To characterize finite-velocity propagation in a finite system, we use the lattice telegrapher equation, which is equivalent to a non-local-in-time master equation with generic jumping models. We studied the solution of this finite-velocity transport equation on a ring. Our analysis focused on finding the phase-space parameters where the probability $P_s\left(t\right)$ shows wave-like behavior. We introduced a novel criterion based on the absolute value of the solution to find the phase-space region where $P_s\left(t\right)⩾0$ for all the sites and times. This criterion helped us to create a diagram illustrating the wave-like nature of the probability distribution for various Markov matrix jump models. Additionally, the Shannon and Fisher measures reveal an oscillatory pattern across the ring for all the jump models studied, implying a time-dependent wavy Cramér–Rao bound. Full article

In this investigation, optical emission spectrometers, a Brinell hardness tester, optical light and scanning microscopes, and X-ray diffraction were used for general metallurgical characterization of the experimental irons in as-cast states. The hole-drilling method was used to assess residual stress distributions under gross and net casting weight conditions. To create experimental irons using the casting process, raw materials were transformed from a solid to a liquid state using an industrial furnace and ladle to melt and cast, respectively. The casting shakeout temperatures for samples A and B were recorded at 60 °C and 180 °C, respectively, after a characteristic stress lattice casting component was allowed to cool for about 1645 min and 1295 min. Chemical analysis verified the experimental hypoeutectic irons of ASTM A532, Type A, Class III, 25%Cr, i.e., high chromium white cast iron alloys. Additionally, it was discovered that micrographs were made of an austenitic-martensitic matrix that contained eutectic M₇C₃ and secondary M₂₃C₆-type carbides. The residual stress distributions were found to be influenced by various carbide and metallic volume fraction proportions, casting section thickness, and casting shakeout duration and temperature. Optimal hardness values, however, were shown to be associated with higher residual stress distributions and an increase in major alloying elements in experimental irons. Consequently, different residual stress distributions are produced by casting shakeout temperatures at lower and higher values under gross and net casting weight conditions. Full article

This study introduces and characterizes a family of quilling-inspired S-shaped unit-cell architectures intended as building blocks for mechanical metamaterials. In contrast to conventional lattice designs based mainly on straight struts, the proposed geometries use continuous curved elements inspired by paper quilling, enabling deformation mechanisms dominated by bending, rotation, and progressive opening of the curved members. By translating quilling’s coiled and spiraled patterns into engineered geometries, nine distinct S-shaped unit cells were fabricated by fused deposition modeling and tested experimentally under uniaxial tensile loading. Finite element analysis was performed to reproduce the tensile response and to assess the influence of geometry on stiffness, stretchability, and energy absorption. The results show that relatively small changes in radii, span lengths, angular distribution, and symmetry produce significant differences in mechanical response. Compact configurations such as S2, S3, and S5 exhibit high stiffness and limited elongation, whereas S9 shows the highest compliance and stretchability. The results indicate that these quilling-inspired architectures provide a tunable design space and have strong potential for applications in energy absorption, adaptive structures, and lightweight load-bearing systems. Full article

Federal post-quantum cryptography migration is scoped around three categories of cryptographic assets: libraries, protocols, and key stores. We argue that this scoping is incomplete. Cryptographic functions and key material can be realized in the parameters of machine-learning models, and the current open-source serialization-focused scanners we evaluated do not detect them. We provide an existence proof: a 30-layer feed-forward ReLU network that realizes AES-128 exactly, with the master key and all eleven round keys resident directly in the layer bias vectors and recoverable by parsing. The construction validates bit-exactly against FIPS 197 and the NIST CAVP AESAVS known-answer subsets across 10⁴ random plaintext-key pairs, including under float32 quantization. We argue analytically—by a sizing analysis rather than empirical construction—that ML-KEM and ML-DSA private keys hide more comfortably in modern weight tensors than AES keys do. The basis is twofold: larger key sizes amortize the construction’s fixed parameter overhead, and the lattice arithmetic underlying these primitives admits more architectural variation than the rigid AES key schedule. Under the harvest-now-decrypt-later threat model, the consequence is direct: any long-lived cryptographic key embedded in an open-weights model artifact distributed today is recoverable by any future party with knowledge of the embedding scheme, with no quantum capability required. We propose an audit primitive—a parameter-space cryptographic recognizer—that screens model artifacts at ingestion through four stages: structural matching against cipher fingerprints, a parametric analysis for bias-and-sign coupling signatures, functional probing for cryptographic input–output behavior, and the integration with cryptographic bill-of-materials tooling as a parameter-resident cryptographic content emission class extending the MBOM-PQC schema. The recognizer is defense-in-depth: it closes the gap for known constructions and architectural fingerprints without claiming completeness against adaptive adversaries. We make no claim that any deployed model contains such an embedding; the contribution is the existence of the capability, the absence of detection in the scanners we evaluated, and the migration-scope consequence. Full article

Extrusion-based three-dimensional food printing requires inks that can be smoothly extruded while maintaining sufficient structural stability after deposition. In this study, gelatin and κ-carrageenan were first mixed and then subjected to post-mixing pH regulation before spray drying, producing composite powders with different structural states. These powders were incorporated into yellow peach pulp gels to prepare fruit-based printing inks, and their printing performance, extrusion behavior, mechanical properties, particle-size distribution, and microstructure were systematically evaluated. The results showed that the structural state formed during gelatin–κ-carrageenan powder preparation was closely associated with the extrusion stability and shape retention of the final inks. Among the tested formulations, the ink prepared with gelatin–κ-carrageenan powder pre-regulated to pH 4.0 exhibited the best overall printability. Although its pore-area fidelity was slightly lower than that of the sample pre-regulated to pH 3.5, it produced more stable multilayer cylinders and better-defined lattice structures. In addition, the pH 4.0 sample showed the lowest and most stable extrusion force and the highest Young’s modulus, indicating a favorable balance between extrusion flowability and post-deposition support. Microstructural observations and particle-size analysis suggested that pH regulation altered the aggregation state and local morphology of the gelatin–κ-carrageenan system. Samples prepared at higher pH values tended to form larger and less uniform aggregates, which was unfavorable for stable extrusion and shape retention. Overall, post-mixing pH regulation of gelatin–κ-carrageenan provides a practical strategy for improving the printing-related properties of fruit-based gel inks. Full article

Dual-material additive manufacturing enables the design of cellular structures with a tailored mechanical response through controlled material distribution and interfacial architecture. In this research, honeycomb structures fabricated by Fused Filament Fabrication (FFF) using dual-material TPU/PLA configurations have been systematically investigated. Particular emphasis is placed on interlocking TPU/PLA joint designs, implemented through tau-shaped and teeth-based geometries, to evaluate their role in load transfer and structural performance. An experimental–analytical model has been developed to characterize the compressive force–displacement response of dual-material honeycombs, capturing the three characteristic deformation regimes—initial stiffness, progressive collapse, and densification—while linking the effective stiffness to the underlying beam-lattice mechanics. The relative contributions of axial and bending deformation mechanisms are quantified through a comparative beam element approach, introducing dimensionless coefficients that reflect the governing deformation mode. The results reveal that the mechanical response is bending-dominated for the examined configurations. The configuration with PLA at the nodes and TPU at the struts exhibits a higher load-carrying capacity and a more stable collapse regime due to a more balanced axial–bending interaction. In contrast, alternative material distributions lead to earlier instability and reduced structural efficiency. The proposed analytical model demonstrates excellent agreement with the experimental data across all configurations. The results demonstrate that properly designed dual-material interlocks can enhance load transfer, decrease stress concentrations, and refine the overall mechanical performance of lightweight cellular structures. Full article

Metal accumulation in cacao (Theobroma cacao L.) cultivation represents an important agronomic and food-safety concern, particularly in acidic tropical soils where cadmium (Cd) and other trace metals can become bioavailable and translocate to plant tissues. Green magnetic nanomaterials offer a potential strategy for reducing metal mobility in agricultural substrates, but their performance depends on surface chemistry, dose, and plant genotype. In this study, we synthesized and evaluated MCRES, defined here as a maghemite–Citrus reticulata extract system, a biofunctionalized γ-Fe₂O₃-based nanosystem prepared by coupling iron oxide nanoparticles (NPs) with a 3% (w/v) Citrus reticulata peel extract. The objective was to determine whether citrus-mediated biofunctionalization could produce a scalable magnetic nanoamendment capable of modifying Cd and naturally occurring Ni partitioning in cacao seedlings. MCRES was recovered magnetically and dried, yielding 8.44 g of product from 10 g of precursor. Rietveld analysis performed in X ray diffractograms confirmed phase-pure cubic γ-Fe₂O₃ with a lattice parameter of 0.8332 nm, a crystallite size of 11.3(1) nm, and satisfactory refinement quality (χ² ≈ 1.34). Transmission electron microscope images showed quasi-spherical NPs with a log-normal size distribution centered at 7.5 nm. Magnetic measurements showed superparamagnetic-like behavior at 300 K, high saturation magnetization values of 62 emu g⁻¹ at 300 K and 71 emu g⁻¹ at 5 K, and elevated effective anisotropy values obtained from the Law of Approach to Saturation fitting. MCRES was applied at 0, 1, 2, 4, and 6 g pot⁻¹ to cacao seedlings containing Cd-amended Ultisol with naturally occurring Ni. Plant responses were genotype and dose dependent: TSH-1188 genotype showed limited dose sensitivity for most biometric variables, whereas ICS-95 genotype showed significant dose effects, with maximum growth at the 2 g pot⁻¹ treatment. Metal-partitioning results indicated that Cd remained comparatively mobile toward shoots, whereas Ni was preferentially retained in roots. In TSH-1188 genotype, the Ni translocation factor decreased from 3.07 in the control to 0.85–1.00 at higher MCRES doses. Compared with previous work on non-biofunctionalized nanomaghemite, these results suggest that citrus-mediated biofunctionalization produces a distinct Cd/Ni partitioning response. Overall, MCRES is recommended as a promising nursery-scale green nanoamendment for reducing metal mobility in cacao cultivation, but its agronomic use should be optimized according to genotype and dose. Future work should include side-by-side comparisons with unfunctionalized γ-Fe₂O₃, Citrus reticulata extract alone, and non-contaminated controls under field conditions to validate its long-term effectiveness and environmental safety. Full article