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

ZHAO Yingmei, ZHAO Yuqing, ZHOU Xingyu et al.

Two metal-organic frameworks （MOFs）， Ce-UiO-66， and Zr-UiO-66， are synthesized using cerium ammonium nitrate （Ce（NH4）2（NO3）6） and zirconium tetrachloride （ZrCl4） as metal salts， and 1，4-benzenedicarboxylic acid （H2BDC） as the organic linker. The crystal structure and morphology of the MOFs are characterized by powder X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The MOFs-modified functional separators are prepared by loading Ce-UiO-66 and Zr-UiO-66 onto one side of commercial Celgard PP separators via vacuum filtration. The electrochemical performance of lithium-sulfur batteries is assembled and tested. The results show that the Ce-UiO-66 modified separator batteries demonstrates optimal electrochemical performance. At a rate of 0.2 C， the initial discharge capacity reaches 1047 mAh·g-1， with a capacity retention rate of 77.5% after 200 cycles and Coulombic efficiency approaching 100%. Under various current rates， the Ce-UiO-66 modified cells deliver discharge capacities of 1281， 945， 768.1， 673.2， 604.7 mAh·g-1 at 0.1， 0.2， 0.5， 1， 2 C， respectively. When returning to 0.1 C， the capacity recovers to 951.6 mAh·g-1 with a capacity retention rate of 74.3%. The above results demonstrate that the redox-active Ce₆-oxo clusters in Ce-UiO-66 can effectively catalyze the conversion reactions of lithium polysulfides （LiPSs） and enhance the redox kinetics. Furthermore， Ce-UiO-66 possesses abundant defects and unsaturated coordination sites， which can effectively anchor LiPSs， mitigate the shuttle effect， and further enhance the electrochemical performance of batteries.

I. Liu, T.C. Bor, P.G. Allison et al.

Additive friction stir deposition (AFSD) enables near-net shape fabrication through layer-by-layer material deposition, depositing feedstock via frictional heat and plastic deformation for applications ranging from component manufacturing to repair. Given aluminum alloys’ favorable strength-to-density ratio and the challenges associated with fusion-based additive manufacturing of aluminum alloys, AFSD has emerged as a solid-state additive manufacturing method that overcomes fusion-based limitations of feedstock and atmospheric control. This review synthesizes the most recent published aluminum alloy AFSD research, examining the relationship between process parameters, microstructural evolution, and mechanical properties. Particularly, we focus on the relationships between process parameters and thermal distribution, thermal cycles on recrystallization and phase transformations, and their resulting influence on hardness, tensile properties, fatigue life, and corrosion resistance. This review also explores AFSD’s applications in recycling, repair, and composites, providing a comprehensive assessment of AFSD of aluminum alloys. Finally, this review presents the current technical challenges and limitations of AFSD and makes recommendations for future research directions.

Salim Barbhuiya, Dibyendu Adak, Comingstarful Marthong et al.

Assam-type houses, traditionally constructed using bamboo, timber, and mud, have long served as climate-adapted, affordable Building in North-East India. With growing demands for low-cost and sustainable Building, this review evaluates material innovations that can enhance the affordability, durability, and sustainability of Assam-type houses. The paper examines traditional materials such as bamboo and thatch, alongside modern innovations like Compressed Stabilized Earth Blocks (CSEB), fly ash bricks, and agro-waste products. Emerging materials, including ferrocement and hempcrete, are assessed for their potential in providing eco-friendly alternatives. Key challenges in the region, such as economic constraints, environmental threats like floods and earthquakes, and material transportation issues, are addressed. Technological advancements, such as prefabricated Building and 3D printing, are discussed for their role in sustainable construction. The review concludes with a focus on policy support, particularly the Pradhan Mantri Awas Yojana (PMAY), and future directions for scaling sustainable, low-cost Building solutions in the region.

Wojciech Polkowski, Paolo Lai Zhong Lo Biundo, Jianmeng Jiao et al.

New ternary Fe-Si-B alloys were developed as potential metallic phase change materials (PCMs) for application in ultra-high temperature latent heat thermal energy storage systems (LHTES). By a thermodynamic re-assessment of the Fe-Si-B system, three new Si-rich (approx. 40–50 wt%) compositions were pre-selected for further analyses. The new alloys can provide very high energy density (even above 1 MWh/m3) at melting temperatures around 1150–1200 °C. Furthermore, new PCM candidates have twice lower B content than already developed Fe-26Si-9B alloy, what is beneficial from the economic point of view. For the sake of experimental validation, the PCM candidates were produced by the arc melting technique. The outputs of thermodynamic calculations were verified in detailed microstructural studies and differential scanning calorimetry experiments. In the case of the newly developed Fe-46Si-5B and already designed Fe-26Si-9B alloy, the energy density higher than 1 MWh/m3 was experimentally confirmed.

I-Te Lu, Dongbin Shin, Mark Kamper Svendsen et al.

Confining electromagnetic fields inside an optical cavity can enhance the light-matter coupling between quantum materials embedded inside the cavity and the confined photon fields. When the interaction between the matter and the photon fields is strong enough, even the quantum vacuum field fluctuations of the photons confined in the cavity can alter the properties of the cavity-embedded solid-state materials at equilibrium and room temperature. This approach to engineering materials with light avoids fundamental issues of laser-induced transient matter states. To clearly differentiate this field from phenomena in driven systems, we call this emerging field cavity materials engineering. In this review, we first present theoretical frameworks, especially, ab initio methods, for describing light-matter interactions in solid-state materials embedded inside a realistic optical cavity. Next, we overview a few experimental breakthroughs in this domain, detailing how the ground state properties of materials can be altered within such confined photonic environments. Moreover, we discuss state-of-the-art theoretical proposals for tailoring material properties within cavities. Finally, we outline the key challenges and promising avenues for future research in this exciting field.

Guohao Gao, Mitsuo Hara, Takahiro Seki et al.

In recent times, there has been a significant surge in research interest surrounding thermo-responsive water-soluble polyacrylamides, primarily due to their intriguing capability to undergo significant solubility changes in water. These polymers exhibit the remarkable ability to shift from a soluble to an insoluble state in response to temperature variations. The capacity of these polymers to dynamically respond to temperature changes opens up exciting avenues for designing smart materials with tunable properties, amplifying their utility across a spectrum of scientific and technological applications. Researchers have been particularly captivated by the potential applications of thermo-responsive water-soluble polyacrylamides in diverse fields such as drug delivery, gene carriers, tissue engineering, sensors, catalysis, and chromatography separation. This study reports the construction and functionalization of polymer gels consisting of a polymer network of polyacrylamide derivatives with nano-sized structural units. Specifically, thermo-responsive polymer gels were synthesized by combining well-defined star-shaped polymers composed of polyacrylamide derivatives with a multifunctional initiator and linking method through a self-accelerating click reaction. The polymerization system employed a highly living approach, resulting in polymer chains characterized by narrow molecular weight distributions. The method’s high functionality facilitated the synthesis of a temperature-responsive block copolymer gel composed of N-isopropyl acrylamide (NIPA) and N-ethyl acrylamide (NEAA). The resulting polymer gel, comprising star-shaped block copolymers of NIPA and NEAA, showcases smooth volume changes with temperature jumps.

Norman O. Birge, Nathan Satchell

The past two decades have seen an explosion of work on Josephson junctions containing ferromagnetic materials. Such junctions are under consideration for applications in digital superconducting logic and memory. In the presence of the exchange field, spin-singlet Cooper pairs from conventional superconductors undergo rapid oscillations in phase as they propagate through a ferromagnetic material. As a result, the ground-state phase difference across a ferromagnetic Josephson junction oscillates between 0 and $π$ as a function of the thickness of the ferromagnetic material. $π$-junctions have been proposed as circuit elements in superconducting digital logic and in certain qubit designs for quantum computing. If a junction contains two or more ferromagnetic layers whose relative magnetization directions can be controlled by a small applied magnetic field, then the junction can serve as the foundation for a memory cell. Success in all of those applications requires careful choices of ferromagnetic materials. Often, materials that optimize magnetic properties do not optimize supercurrent propagation, and vice versa. In this review we discuss the significant progress that has been made in identifying and testing a wide range of ferromagnetic materials in Josephson junctions over the past two decades. The review concentrates on ferromagnetic metals, partly because eventual industrial applications of ferromagnetic Josephson junctions will most likely start with metallic ferromagnets (either in all metal junctions or junctions containing also an insulating layer). We will briefly mention work on non-metallic barriers, including ferromagnetic insulators, and some of the exciting work on spin-triplet supercurrent in junctions containing noncollinear magnetic inhomogeneity.

Die Lu, Xinyao Fu, Dong Guo et al.

Abstract Two‐dimensional (2D) high‐entropy alloys (HEAs) have emerged as promising electrocatalysts due to the benefits of polymetallic coordination and robust electrical conductivity. However, the multiple elements in 2D HEAs pose challenges in achieving a uniform composition and maintaining a 2D limit morphology, complicating their structural characterization. Furthermore, even minor adjustments to the composition can significantly alter the properties of 2D HEAs, underscoring the need for a deeper understanding of their structure–property relationships to advance synthesis and application. Therefore, this review critically examines the intrinsic factors influencing synthesis methods and the practical applications of 2D HEAs in electrocatalysis for sustainable energy conversion. The urgency is emphasized for developing new synthesis techniques, enhancing advanced characterization methods, and gaining profound insights into the functional mechanisms of 2D HEAs.

XUE Ruiying, MENG Yunyun, LIU Jun

Superoleophobic refers to the phenomenon that the contact angle (CA) of the oil droplet with low surface tension on the solid surface is greater than 150° as well as the sliding angle (SA) is less than 10°. However, due to the low surface tension of organic liquids, the construction of superoleophobic surfaces was relatively difficult. Inspired by springtail, re-entrant structure has become a breakthrough to solve this problem.Together with surface chemical composition modification and surface roughness, it has been introduced into the design and manufacturing system of superoleophobic surface. Several classical wetting models such as Young model, Wenzel model, Cassie-Baxter model were introduced, the design methods of superoleophobic surfaces were elaborated from the structural structure and chemical composition, and the research progress of superoleophobic surface preparation technologies such as electrospinning, sol-gel method, deposition method, etching method and laser processing was discussed, the oleophobic properties of various surfaces under test liquids with different surface tension were summarized. Finally, the research direction of superoleophobic surface was prospected, that is, low cost, simple operation, environmental friendly and excellent physical and chemical properties of the obtained surfaces. The preparation technology of superoleophobic surfaces would be further explored.

Dongxue Du, Jiamian Hu, Jason K Kawasaki

Strain is powerful for discovery and manipulation of new phases of matter; however, the elastic strains accessible to epitaxial films and bulk crystals are typically limited to small ($<2\%$), uniform, and often discrete values. This Perspective highlights new directions for strain and strain gradient engineering in free-standing single crystalline membranes of quantum materials. Membranes enable large ($\sim 10\%$), continuously tunable strains and strain gradients via bending and rippling. Moreover, strain gradients break inversion symmetry to activate polar distortions, ferroelectricity, chiral spin textures, novel superconductivity, and topological states. Recent advances in membrane synthesis by remote epitaxy and sacrificial etch layers enable extreme strains in new materials, including transition metal oxides and Heusler compounds, compared to natively van der Waals (vdW) materials like graphene. We highlight new opportunities and challenges for strain and strain gradient engineering in membranes of non-vdW materials.

Choongman Moon, Byungha Shin

Abstract A photoelectrochemical (PEC) water-splitting device integrates a photovoltaic cell and electrocatalysts into a single device to produce hydrogen fuel from water using solar irradiance. The major driving force behind PEC research is that it can potentially be a cost-efficient way to produce hydrogen in a renewable way, however, current PEC devices for hydrogen production are not economically viable yet. This review provides comprehensive discussions on the major challenges on practical solar hydrogen production by PEC from the standpoint of device structure and light absorber materials. We started by systematically classifying PEC device structures based on the electrical junctions on the light absorber materials. Based on the classification scheme, we showed that the choices of a device structure and light absorber materials are cross-linked in current PEC studies and affects electron/ion transport in a PEC device. The correlation between the device structure and materials underlines the necessity of reviewing the light absorber materials for the top and bottom cells in a tandem PEC device as a whole. We categorize the light absorber materials based on their crustal abundance because it is a major factor that determines device structure and scalability in TW-scale, and discuss their influence on the efficiency, stability, and scalability of a PEC water-splitting system.

ZHAO Lei, LIANG Qichao, LIU Chuanlong, WANG Tianguo

At present,there are few studies focusing on the effect of negative bias voltage on the corrosion resistance of TiAlN films deposited by arc ion plating.In this paper,TiAlN films were deposited on M2 high speed steel by arc ion plating,and scanning electron microscope (SEM),X-ray diffraction (XRD),electrochemical test and other methods were used to study the influences of negative bias voltage on substrate on the microstructure,surface morphology and corrosion resistance of the as-prepared films.Results showed that the negative bias voltage was an important process parameter affecting the surface morphology of TiAlN films deposited by arc ion plating.A proper negative bias voltage could effectively improve the morphology and compactness of the surface film and reduce the size and number of large molten droplets on the surface.The main phase of TiAlN films was AlTi3N(111),and the films mainly grew along the (111) direction.When the negative bias voltage was increased,a new reaction would occur and a Ti2AlN (100) diffraction peak would appear.With the increase of the negative bias voltage on substrate,the microhardness of the films increased first and then decreased.When the negative bias voltage was 150 V,the microhardness reached the maximum value of 2 725 HV,the relative corrosion rate was the lowest,and the corrosion resistance was the best.

Mahasweta Bagchi, Jens Brede, Yoichi Ando

The superconducting materials family of doped Bi2Se3 remains intensively studied in the field of condensed matter physics due to strong experimental evidence for topologically non-trivial superconductivity in the bulk. However, at the surface of these materials, even the observation of superconductivity itself is still controversial. We use scanning tunneling microscopy (STM) down to 0.4 K to show that on the surface of bulk superconducting SrxBi2Se3, no gap in the density of states is observed around the Fermi energy as long as clean metallic probe tips are used. Nevertheless, using scanning electron microscopy and energy-dispersive X-ray analysis, we find that micron-sized flakes of SrxBi2Se3 are easily transferred from the sample onto the STM probe tip and that such flakes consistently show a superconducting gap in the density of states. We argue that the superconductivity in SrxBi2Se3 crystals does not extend to the surface when the topological surface state (TSS) is intact, but in micro-flakes the TSS has been destroyed due to strain and allows the superconductivity to extend to the surface. To understand this phenomenon, we propose that the local electric field, always found in electron doped Bi2Se3 in the presence of the TSS due to an intrinsic upward band bending, works against superconductivity at the surface.

Ying Han, Jielai Yang, Weiwei Zhao et al.

The occurrence of osteoarthritis (OA) is highly associated with the reduced lubrication property of the joint, where a progressive and irreversible damage of the articular cartilage and consecutive inflammatory response dominate the mechanism. In this study, bioinspired by the super-lubrication property of cartilage and catecholamine chemistry of mussel, we successfully developed injectable hydrogel microspheres with enhanced lubrication and controllable drug release for OA treatment. Particularly, the lubricating microspheres (GelMA@DMA-MPC) were fabricated by dip coating a self-adhesive polymer (DMA-MPC, synthesized by free radical copolymerization) on superficial surface of photo-crosslinked methacrylate gelatin hydrogel microspheres (GelMA, prepared via microfluidic technology), and encapsulated with an anti-inflammatory drug of diclofenac sodium (DS) to achieve the dual-functional performance. The tribological test and drug release test showed the enhanced lubrication and sustained drug release of the GelMA@DMA-MPC microspheres. In addition, the functionalized microspheres were intra-articularly injected into the rat knee joint with an OA model, and the biological tests including qRT-PCR, immunofluorescence staining assay, X-ray radiography and histological staining assay all revealed that the biocompatible microspheres provided significant therapeutic effect against the development of OA. In summary, the injectable hydrogel microspheres developed herein greatly improved lubrication and achieved sustained local drug release, therefore representing a facile and promising technique for the treatment of OA.

Qianheng Du, Lijun Wu, Huibo Cao et al.

Abstract Iron diantimonide is a material with the highest known thermoelectric power. By combining scanning transmission electron microscopic study with electronic transport neutron, X-ray scattering, and first principle calculation, we identify atomic defects that control colossal thermopower magnitude and nanoprecipitate clusters with Sb vacancy ordering, which induce additional phonon scattering and substantially reduce thermal conductivity. Defects are found to cause rather weak but important monoclinic distortion of the unit cell P n n m → P m. The absence of Sb along [010] for high defect concentration forms conducting path due to Fe d orbital overlap. The connection between atomic defect anisotropy and colossal thermopower in FeSb2 paves the way for the understanding and tailoring of giant thermopower in related materials.

Qiangu Yan, Rachel Arango, Jinghao Li et al.

Carbon foams have been prepared using Kraft lignin as the solely resource. No catalysts, foaming/blowing agents, surfactants, and/or crosslinking agents are used for the foam preparation. The process includes pressing carbon foam precursors into molds followed by formation of lignin foam through heating and carbonization/graphitization of the lignin derived foams. The resultant lignin carbon foam (LCF) has an open-cell structure with densities ranging from about 0.18 g/cm3 to 0.68 g/cm3. The compressive strengths of LCFs increase with increasing of bulk density, from 7.03 ± 1.25 MPa of LCF1 to 30.16 ± 2.41 MPa of LCF7, and thermal conductivity is strongly influenced by the bulk density with increase from 0.21 ± 0.02 W/(m·K) to 0.75 ± 0.01 W/(m·K). The bulk electrical conductivities of LCF samples increase with increasing of bulk densities from 701 S/m to 2031S/m. The LCF samples were evaluated for resistance to fire and native subterranean termites. LCF samples exhibit excellent fire resistance, no damage occurred when the LCF sample was exposed to an oxyacetylenic flame in air over 1050 °C for more than 3 min. Termite testing showed no degradation to the LCF samples after the evaluation.

Nesrine Ben Saber, Amine Mezni, Arwa Alrooqi et al.

In the present study, an attempt has been made to design ternary multifunctional nanocomposite photocatalyst based on Au@Pt-TiO _2 core–shell nanoparticles anchored onto nano-graphene oxide (nano-GO) through facile one-pot solvothermal process. Evaluation of UV and visible light photocatalytic activities against MB dye and diuron pesticide decomposition, demonstrated a remarkable enhancement in photocatalytic performances, which indicates their potential as powerful photocatalyst. The enhancement of the photocatalytic activity of the designed ternary Au@Pt-TiO _2 /nano-GO could be attributed to the heterojunction structure and to the enhanced charge separation and light absorption of nano-GO and Au, Pt NPs. Before application, the ternary Au@Pt-TiO _2 /nano-GO photocatalyst was fully characterised (structural, morphology and composition) using powerful instruments including x-ray diffraction powder (XRD), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM). The optical response was investigated using UV-Visible spectrophotometer. The ternary Au@Pt-TiO _2 /nano-GO photocatalyst exhibits high crystallinity and high purity with uniform behaviour on size and shape. The hybrid Au@Pt-TiO _2 nanoparticles were found to be well dispersed on nano-GO surface, which make this heterojunction very efficient for photocatalytic applications.

Alex Brasington, Christopher Sacco, Joshua Halbritter et al.

Automated fiber placement (AFP) is a composite manufacturing technique used to fabricate complex advanced air vehicle structures that are lightweight with superior qualities. The AFP process is intricate and complex with various phases of design, process planning, manufacturing, and inspection. An understanding of each of these phases is necessary to achieve the highest possible manufacturing quality. This literature review aims to summarize the entire AFP process from the design of the structure through inspection of the manufactured part to generate an overall understanding of the lifecycle of AFP manufacturing. The review culminates with highlighting the challenges and future directions for AFP with the goal of achieving a closed loop AFP process.

Valery I. Levitas

Review of selected fundamental topics on the interaction between phase transformations, fracture, and other structural changes in inelastic materials is presented. It mostly focuses on the concepts developed in the author's group over last three decades and numerous papers that affected us. It includes a general thermodynamic and kinetic theories with sharp interfaces and within phase field approach. Numerous analytical (even at large strains) and numerical solutions illustrate the main features of the developed theories and their application to the real phenomena. Coherent, semicoherent, and noncoherent interfaces, as well as interfaces with decohesion and with intermediate liquid (disordered) phase are discussed. Importance of the surface- and scale-induced phenomena on interaction between phase transformation with fracture and dislocations as well as inheritance of dislocations and plastic strains is demonstrated. Some nontrivial phenomena, like solid-solid phase transformations via intermediate (virtual) melt, virtual melting as a new mechanism of plastic deformation and stress relaxation under high strain rate loading, and phase transformations and chemical reactions induced by plastic shear under high pressure are discussed and modeled.

Wen-Ten Kuo, Her-Yung Wang, Chun-Ya Shu et al.