Hasil untuk "Materials of engineering and construction. Mechanics of materials"

Boris Tsvelikhovskiy, Ilya Safro, Yuri Alexeev

Constructing effective mixer Hamiltonians is essential for enhancing the performance of the quantum approximate optimization algorithm (QAOA) in solving combinatorial optimization problems. In this work, we develop a systematic methodology for designing QAOA mixers that align with the symmetries of the classical objective function, with the goal of achieving values (mean, median, and minimum over multiple runs) that are closer to the true optimum. Our main idea is to design QAOA operators that are explicitly adapted to the action of symmetry groups on the Hilbert space. We focus on subgroups of the symmetric group <inline-formula><tex-math notation="LaTeX">$ S_{d}$</tex-math></inline-formula>, where <inline-formula><tex-math notation="LaTeX">$ d = 2^\ell$</tex-math></inline-formula>, to ensure compatibility with qudit-based quantum architectures. In particular, we construct QAOA mixers invariant under the full symmetric group <inline-formula><tex-math notation="LaTeX">$ S_{d}$</tex-math></inline-formula> as well as its cyclic subgroup <inline-formula><tex-math notation="LaTeX">$ \mathbb {Z}_{d} \subset S_{d}$</tex-math></inline-formula>. These constructions are natural in that they respect the decomposition of the Hilbert space into isotypic components under the symmetry group action. Notably, to the best of the authors&#x2019; knowledge, the QAOA algorithm based on the <inline-formula><tex-math notation="LaTeX">$ \mathbb {Z}_{d}$</tex-math></inline-formula>-invariant mixer provides the first example of a QAOA protocol whose dynamics (up to final measurement) are confined entirely within a nontrivial irreducible representation of a symmetry group of the objective function. Although our work does not investigate the benefits of exploiting such subspaces as computational resources, we think that the very realization of a variational algorithm whose evolution is restricted to a nontrivial symmetry-adapted subspace is of fundamental conceptual interest. We provide closed-form expressions for these mixers, together with explicit quantum circuit implementations. To empirically evaluate our approach, we compare QAOA variants employing the standard mixer <inline-formula><tex-math notation="LaTeX">$B = \sum X_{i}$</tex-math></inline-formula> with those using our proposed Hamiltonians <inline-formula><tex-math notation="LaTeX">$H_{M}$</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">$H_\chi$</tex-math></inline-formula> on edge coloring and graph partitioning problems. Across multiple graph instances, our symmetry-adapted mixers consistently yield objective values closer to the optimum, demonstrating statistically significant improvements over classical baselines.

Piyush Kumar Soni, Amit Tiwari, S. N. V. J. Devi Kosuru et al.

Abstract This research presents a wide mathematical framework for modeling, developing, and optimizing the pressure vessels in hydrogen storage tanks using state-of-the-art solid materials. The emphasis is on metal hybrid storage tanks because these systems have been extensively studied from an experimental and theoretical perspective in the literature, and if the current R&D efforts are successful in bringing the required technology to market, they should offer several advantages. It is found that better cooling is essential during the hydrogen filling process of the storage tank in order to shorten the time required for hydrogen storage. CoMoCrSi + Cr2C3 material comprised the inner layer of the pressure vessel, while Inconel 713 made up the exterior layer. Their thicknesses were 10 mm and 8 mm, respectively. The pressure vessel’s response to various conditions could be assessed through static structural analysis in Ansys Workbench. This particular study aimed at investigating whether a square sample had met the requirements of storing hydrogen gas. Promising results indicate that the multi-layered design used for the pressure vessel is well-suited for hydrogen storage. This may be deduced from its ability to withstand pressure and maintain structural integrity, and this exceeds what other cylinder materials can do. Through sophisticated modeling tools and advanced materials science, this project demonstrates how improvements in hydrogen storage technology can contribute to sustainable energy development.

Hafiz Saad Khaliq, Min-Seok Kim, Hak-Rin Kim

Ultraviolet (UV) dielectric metasurfaces featuring ultrahigh-quality-factor (high-Q) resonances are essential for advanced applications such as biosensing, nonlinear optics, and spectral filtering. However, achieving high-Q resonances in the UV range remains a significant challenge due to inherent material limitations and fabrication complexities. In this study, we introduce a single-layer UV metasurface comprising wide-bandgap silicon nitride (SiNx) cross-shaped nano-resonators that support spin-selective, dual quasi-bound states in the continuum (q-BICs). By breaking in-plane symmetry, a symmetry-protected mode is split into two distinct resonances—each selectively excited by left- and right-handed circularly polarized light—resulting in near-unity circular dichroism (CD) and Q-factors exceeding 103. These resonances can be tuned through geometric design, angular rotation, and modulation of the surrounding analyte’s refractive index, all while preserving their high-Q characteristics. Notably, angular perturbation enhances the Q-factor from approximately 693 to 1875 by effectively controlling radiation leakage. Furthermore, analyte layers with dielectric constant ranging from 1.00 to 1.20 induce resonance shifts of approximately 10–12 nm, enabling independent tuning of both CD and Q. This fabrication-compatible platform presents a promising pathway toward next-generation UV chiral photonic technologies, including ultrasensitive biosensors, low-threshold lasers, and nonlinear optical devices.

V.G. Germinari, R.S. Miranda, A.B. Rezende et al.

In countries with continental dimensions like Brazil, railways transport production from inland regions to ports and the international market. It is essential to note that researchers and engineers in the railway sector are constantly striving to reduce operational and maintenance costs associated with wheel-rail contact while maintaining high standards of quality, safety, and operational predictability. In this context, wheels are one of the most costly components in railway acquisition and maintenance, representing a significant factor in transport safety. Additionally, their manufacturing process can involve either forging or casting. Therefore, the manufacturing process can offer the best cost-benefit ratio to meet the diverse demands of the railway sector — longer wear/fatigue life with lower costs. This study aimed to analyze the effects of the manufacturing process of the cast and forged microalloyed railway wheels, with similar microstructure, hardness, and equivalent carbon content, on the metallurgical defects formation and tribological properties. To support material characterization, optical microscopy, scanning electron microscopy, hardness measurements, ASTM E45 standards for evaluating metallurgical defects, twin-disc wear tests, Raman spectroscopy, and statistical analyses were conducted to compare the defects and cracks developed in railway steels.

Viet-Anh Ha, Feliciano Giustino

2D semiconductors offer a promising pathway to replace silicon in next-generation electronics. Among their many advantages, 2D materials possess atomically-sharp surfaces and enable scaling the channel thickness down to the monolayer limit. However, these materials exhibit comparatively lower charge carrier mobility and higher contact resistance than 3D semiconductors, making it challenging to realize high-performance devices at scale. In this work, we search for high-mobility 2D materials by combining a high-throughput screening strategy with state-of-the-art calculations based on the ab initio Boltzmann transport equation. Our analysis singles out a known transition metal dichalcogenide, monolayer WS$_2$, as the most promising 2D semiconductor, with the potential to reach ultra-high room-temperature hole mobilities in excess of 1300 cm$^2$/Vs should Ohmic contacts and low defect densities be achieved. Our work also highlights the importance of performing full-blown ab initio transport calculations to achieve predictive accuracy, including spin-orbital couplings, quasiparticle corrections, dipole and quadrupole long-range electron-phonon interactions, as well as scattering by point defects and extended defects.

Nirma Kumari, Jaywan Chung, Seunghyun Oh et al.

Thermoelectric (TE) technology enables direct heat-to-electricity conversion and is gaining attention as a clean, fuel-saving, and carbon-neutral solution for industrial, automotive, and marine applications. Despite nearly a century of research, apart from successes in deep-space power sources and solid-state cooling modules, the industrialization and commercialization of TE power generation remain limited. Since the new millennium, nanostructured bulk materials have accelerated the discovery of new TE systems. However, due to limited access to high-temperature heat sources, energy harvesting still relies almost exclusively on BiTe-based alloys, which are the only system operating stably near room temperature. Although many BiTe-based compositions have been proposed, concerns over reproducibility, reliability, and lifetime continue to hinder industrial adoption. Here, we aim to develop reference BiTe-based thermoelectric materials through data-driven analysis of Starrydata2, the world's largest thermoelectric database. We identify Bi0.46Sb1.54Te3 and Bi2Te2.7Se0.3 as the most frequently studied ternary compositions. These were synthesized using hot pressing and spark-plasma sintering. Thermoelectric properties were evaluated with respect to the processing method and measurement direction. The results align closely with the median of reported data, confirming the representativeness of the selected compositions. We propose these as reference BiTe materials, accompanied by transparent data and validated benchmarks. Their use can support the standardization of TE legs and modules while accelerating performance evaluation and industrial integration. We further estimated the performance of a thermoelectric module made from the reference composition, which gives the power output of over 2.51 W and an efficiency of 3.58% at a temperature difference of 120 K.

Jing Meng, Huali Yang, Yu Shen et al.

Noncoplanar spin textures usually exhibit a finite scalar spin chirality (SSC) that can generate effective magnetic fields and lead to additional contributions to the Hall effect, namely topological or unconventional anomalous Hall effect (UAHE). Unlike topological spin textures (e.g., magnetic skyrmions), materials that exhibit fluctuation-driven SSC and UAHE are rare. So far, their realization has been limited to either low temperatures or high magnetic fields, both of which are unfavorable for practical applications. Identifying new materials that exhibit UAHE in a low magnetic field at room temperature is therefore essential. Here, we report the discovery of a large UAHE far above room temperature in epitaxial Fe$_3$Ga$_4$ films, where the fluctuation-driven SSC stems from the field-induced transverse-conical-spiral phase. Considering their epitaxial nature and the large UAHE stabilized at room temperature in a low magnetic field, Fe$_3$Ga$_4$ films represent an exciting, albeit rare, case of a promising candidate material for spintronic devices.

Subham Ghosh, Abhishek Tewari

The rapid discovery of materials is constrained by the lack of large, machine-readable datasets that couple performance metrics with structural context. Existing databases are either small, manually curated, or biased toward first principles results, leaving experimental literature underexploited. We present an agentic, large language model (LLM)-driven workflow that autonomously extracts thermoelectric and structural-properties from about 10,000 full-text scientific articles. The pipeline integrates dynamic token allocation, zeroshot multi-agent extraction, and conditional table parsing to balance accuracy against computational cost. Benchmarking on 50 curated papers shows that GPT-4.1 achieves the highest accuracy (F1 = 0.91 for thermoelectric properties and 0.82 for structural fields), while GPT-4.1 Mini delivers nearly comparable performance (F1 = 0.89 and 0.81) at a fraction of the cost, enabling practical large scale deployment. Applying this workflow, we curated 27,822 temperature resolved property records with normalized units, spanning figure of merit (ZT), Seebeck coefficient, conductivity, resistivity, power factor, and thermal conductivity, together with structural attributes such as crystal class, space group, and doping strategy. Dataset analysis reproduces known thermoelectric trends, such as the superior performance of alloys over oxides and the advantage of p-type doping, while also surfacing broader structure-property correlations. To facilitate community access, we release an interactive web explorer with semantic filters, numeric queries, and CSV export. This study delivers the largest LLM-curated thermoelectric dataset to date, provides a reproducible and cost-profiled extraction pipeline, and establishes a foundation for scalable, data-driven materials discovery beyond thermoelectrics.

Hongqiang Ma, Shaochen Zhang, Hao Fu et al.

Büşra Nasuhoglu, Emrah Çakmakçi, Memet Vezir Kahraman

Abstract Herein, this work reports the facile synthesis of a dimer diamine‐based autocatalytic polyol (ACP) and its use in polyurethane foam preparation. The ACP, namely TETRAOL is synthesized in one step, without using solvent, and with 100% atom economy. Additionally, a phosphorous‐modified polyol is synthesized by using 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and castor oil. In this study, all of the polyol components of the foams are of vegetable oil origin, and amine or tin‐based auxiliary catalysts are not used. The structures of the synthesized autocatalytic polyol as well as other bio‐polyols are characterized by Fourier‐transform infrared (FTIR) and Nuclear magnetic resonance (NMR) spectroscopies. The densities, rise and gel time values, and thermal and mechanical properties of the foams are determined and compared to foams prepared by using a petroleum‐based commercial ACP. The bio‐based TETRAOL‐containing foams display comparable densities and improve thermal properties but longer rise and gel time values concerning the foam prepared by using the commercial ACP.

Salma Majidah, Lavita Nuraviana Rizalputri, Eduardus Ariasena et al.

Integration of gold nanoparticles onto electrochemical biosensor electrodes has been widely conducted to improve the performance of biosensors. Gold nanospikes (AuNS), as one of the gold nanoparticle morphologies, can be integrated into biosensors through electrodeposition and has the potential to immobilize bioreceptor on biosensors using the self-assembled monolayer (SAM) method. This paper examines the potential of AuNS-deposited Screen-Printed Carbon Electrodes (SPCEs) on immobilizing enzymes as label-based electrochemical biosensor by evaluating the optimum parameter for glucose oxidase (GOx) enzyme immobilization on the SPCE that consists of incubation time and concentration of SAM molecule—L-cysteine—and GOx enzyme, then reviews its performances. The developed biosensor exhibits excellent performance in detecting glucose (linear range of 0.2–15 mM and limit of detection (LOD) of 116 µM), with good selectivity against uric acid, urea, ascorbic acid, dopamine, and lactic acid, and superiority towards gold nanosphere modified biosensor.

Keita Ogura, Yoimi Kojima, Masato Imai et al.

Trailing-edge noise (TE noise) is an aeroacoustic sound radiated from an isolated airfoil in the specific ranges of low-speed flow. We used a pulsed laser as an actuator to reduce the TE noise without modifying the airfoil’s surface. The wind tunnel test was conducted to verify the capability of an Nd:YAG laser as the actuator. The laser beam was focused into the air just outside the velocity boundary layer on the lower side of an NACA0012 airfoil. The experimental result shows that the TE noise is suppressed for a certain period after beam irradiations. We then analyzed the physical mechanism of the noise reduction with the laser actuation by the implicit large eddy simulation (ILES), a high-fidelity numerical method for computational fluid dynamics (CFD). The numerical investigations indicate that the pulsed energy deposition changes the unstable velocity amplification mode of the boundary layer, the source of an acoustic feedback loop radiating the TE noise, to another mode that does not generate the TE noise. The sound wave attenuation is observed once the induced velocity fluctuations and consequently generated vortices sweep out the flow structure of the unstable mode. We also examined the effect of the laser irradiation zone’s shape by numerical simulations. The results show that the larger irradiation zone, which introduces the disturbances over a wider range in the span direction, is more effective in reducing the TE noise than the shorter focusing length with the same energies.

Elizaveta B. Kalika, Alexey V. Verkhovtsev, Mikhail M. Maslov et al.

A computational approach combining dispersion-corrected density functional theory (DFT) and classical molecular dynamics is employed to characterize the geometrical and thermo-mechanical properties of a recently proposed 2D transition metal dihalide NiCl$_2$. The characterization is performed using a classical interatomic force field whose parameters are determined and verified through the comparison with the results of DFT calculations. The developed force field is used to study the mechanical response, thermal stability, and melting of a NiCl$_2$ monolayer on the atomistic level of detail. The 2D NiCl$_2$ sheet is found to be thermally stable at temperatures below its melting point of ~695 K. At higher temperatures, several subsequent structural transformations of NiCl$_2$ are observed, namely a transition into a porous 2D sheet and a 1D nanowire. The computational methodology presented through the case study of NiCl$_2$ can also be utilized to characterize other novel 2D materials, including recently synthesized NiO$_2$, NiS$_2$, and NiSe$_2$.

WEI Xiao - jing, GAO Qiu - ying, SHI Xin, LIU Dong - mei

In order to solve the problem of acid corrosion in crude oil extraction, two double condensed Schiff base corrosion inhibitors XFJ - 1 and XFJ - 2 were synthesized by the solvent method. The corrosion inhibition performance at the environment of 90 ℃ and 15%(mass fraction) HCl was evaluated by static weightless method and polarization curve method, and the corrosion inhibition mechanism of XFJ - 1 and XFJ - 2 was explained by simulation method from the molecular level. Results showed that when the mass fraction of the two inhibition was 1.0%, respectively, the corrosion inhibition efficiency of the two corrosion inhibitors reached 82.90% and 99.46%, respectively, and simultaneously suppressed the cathodic and anodic reactions of N80 steel. The adsorption forms were consistent with the Langmuir adsorption isotherm model. The simulation results indicated that the corrosion inhibitor molecules would mainly accept or provide electrons through the benzene ring and the C=N double bond. The reactivity and adsorption energy of the XFJ - 2 corrosion inhibitor were greater than those of XFJ - 1, which was also consistent with the experimental data, indicating that the corrosion inhibition effect of XJF - 2 was better than that of XJF - 1.

A. Wade, T. M. M. Heenan, M. Kok et al.

Abstract Particle micro-cracking is a major source of performance loss within lithium-ion batteries, however early detection before full particle fracture is highly challenging, requiring time consuming high-resolution imaging with poor statistics. Here, various electrochemical cycling (e.g., voltage cut-off, cycle number, C-rate) has been conducted to study the degradation of Ni-rich NMC811 (LiNi0.8Mn0.1Co0.1O2) cathodes characterized using laboratory X-ray micro-computed tomography. An algorithm has been developed that calculates inter- and intra-particle density variations to produce integrity measurements for each secondary particle, individually. Hundreds of data points have been produced per electrochemical history from a relatively short period of characterization (ca. 1400 particles per day), an order of magnitude throughput improvement compared to conventional nano-scale analysis (ca. 130 particles per day). The particle integrity approximations correlated well with electrochemical capacity losses suggesting that the proposed algorithm permits the rapid detection of sub-particle defects with superior materials statistics not possible with conventional analysis.

Changhua Li, Yunlong Su, Cuiwei Zhang et al.

Recently, the hexagonal phase of ternary transition metal pnictides TT'X (T = Zr, Hf; T'= Ru; X = P, As), which are well-known noncentrosymmetric superconductors, were predicted to host nontrivial bulk topology. In this work, we systematically investigate the electronic responses of ZrRuAs to external pressure. At ambient pressure, ZrRuAs show superconductivity with Tc ~ 7.74 K, while a large upper critical field ~ 13.03 T is obtained for ZrRuAs, which is comparable to the weak-coupling Pauli limit. The resistivity of ZrRuAs exhibits a non-monotonic evolution with increasing pressure. The superconducting transition temperature Tc increases with applied pressure and reaches a maximum value of 7.93 K at 2.1 GPa, followed by a decrease. The nontrivial topology is robust and persists up to the high-pressure regime. Considering both robust superconductivity and intriguing topology in this material, our results could contribute to studies of the interplay between topological electronic states and superconductivity.

Zhi-Feng Huang

The growth and microstructural properties of ternary monolayers of two-dimensional hexagonal materials are examined, including both individual two-dimensional crystalline grains and in-plane heterostructures, multijunctions, or superlattices. The study is conducted through the development of a ternary phase field crystal model incorporating sublattice ordering and the coupling among the three atomic components. The results demonstrate that a transition of compositional pattern or modulation in this type of two-dimensional ternary crystals, from phase separation to geometrically frustrated lattice atomic ordering, can be controlled via the varying degree of energetic preference of heteroelemental neighboring over the homoelemental ones. Effects of growth and system conditions are quantitatively identified through numerical calculations and analyses of interspecies spatial correlations and the degree of alloy intermixing or disordering. These findings are applied to simulating the growth of monolayer lateral heterostructures with atomically sharp heterointerface, and via the sequential process of edge-epitaxy, the formation of the corresponding superlattices or structures with multiple heterojunctions, with outcomes consistent with recent experiments of in-plane multi-heterostructures of transition metal dichalcogenides. Also explored is a distinct type of alloy-based lateral heterostructures and multijunctions which integrate ternary ordered alloy domains with the adjoining blocks of binary compounds, providing a more extensive variety of two-dimensional heterostructural materials.

Dai-Nam Le, Pablo Rodriguez-Lopez, Lilia M. Woods

The van der Waals (vdW) interaction plays a prominent role between neutral objects at separations where short ranged chemical forces are negligible. This type of dispersive coupling is determined by the interplay between geometry and response properties of the materials making up the objects. Here, we investigate the vdW interaction between 1D, 2D, and 3D standard and Dirac materials within the Random Phase Approximation, which takes into account collective excitations originating from the electronic Coulomb potential. A comprehensive understanding of characteristic functionalities and scaling laws are obtained for systems with parabolic energy dispersion (standard materials) and crossing linear bands (Dirac materials). By comparing the quantum mechanical and thermal limits the onset of thermal fluctuations in the vdW interaction is discussed showing that thermal effects are significantly pronounced at smaller scales in reduced dimensions.

S. Kundu, A. Pal, Amit Chauhan et al.

Double perovskite-based magnets wherein frustration and competition between emergent degrees of freedom are at play can lead to novel electronic and magnetic phenomena. Herein, we report the electronic structure and magnetic properties of an ordered double perovskite material Ho2CoMnO6. In the double perovskite with general class A2BB'O6, the octahedral B and B'-site has a distinct crystallographic site. The Rietveld refinement of XRD data reveals that Ho2CoMnO6 crystallizes in the monoclinic P21/n space group. The X-ray photoelectron spectroscopy confirms the charge state of cations present in this material. The temperature dependence of magnetization and specific heat exhibit a long-range ferromagnetic ordering at Tc ~ 76 K owing to the presence of super exchange interaction between Co2+ and Mn4+ moments. Furthermore, the magnetization isotherm at 5 K shows a hysteresis curve that confirms ferromagnetic behavior of this double perovskite. We observed a re-entrant glassy state in the intermediate temperature regime, which is attributed to inherent anti-site disorder and competing interactions. A large magnetocaloric effect has been observed much below the ferromagnetic transition temperature. The temperature-dependent Raman spectroscopy studies support the presence of spin-phonon coupling and short-range order above Tc in this double perovskite. The stabilization of magnetic ordering and charge states is further analyzed through electronic structure calculations. The latter also infers the compound to be a narrow band gap insulator with the gap arising between the lower and upper Hubbard Co-d subbands. Our results demonstrate that anti-site disorder and complex 3d-4f exchange interactions in the spin-lattice account for the observed electronic and magnetic properties in this promising double perovskite material.

Nan Yang, Yifan Song, Jinlun Huang et al.

Lattices with engineered properties are significant for engineering applications in the energy, aerospace, optics and medical sectors. Current additive manufacturing (AM) combined with computer-aided design (CAD) methods are not flexible enough to create multi-substructure lattices with locally varying geometrical features and mechanical properties. For example, if the struts of one substructure correspond spatially to the void of another substructure in the hybrid region, the resulting structure is disconnected there. When the number of substructures is large, such a problem becomes inevitable and intractable. Here we propose a new AM &amp; CAD method integrating all the processes of designing a complex lattice structure, such as subspace partitioning, substructure rotation, filling in each subspace and connection, and hybrid region stiffness tuning. This method provides a general framework for designing heterogeneous lattice structures with disorder, gradient and hybrid features. Additionally, we numerically and experimentally investigate the effectiveness of our hybrid region stiffness tuning method. Using this new method, the problem of low volume fraction or disconnection in the hybrid region in multi-substructure lattices is overcome, and the resulting structures can be generated for analysis or fabrication by any suitable AM technique.