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The rare earth-containing Lu 2 AC (A=Au, Al, Ga, In, Si, Ge, Sn, Pb, P, As, Se, Te) ceramics are studied computationally. The thermal, mechanical, and thermodynamic stabilities are first investigated, where all compounds are stable, and then the electronic, mechanical, and conductive properties are calculated. For Lu 2 AC (A=Si, Ge, Sn, Pb), the Young's modulus and hardness decrease with the increasing atomic number of A element, similarly for Lu 2 AC (A=P, As) and Lu 2 AC (A=Se, Te). However, Lu 2 AC (A=Al, Ga, In) does not follow this trend, first decreasing and then increasing. Overall, Lu 2 GaC is the softest and Lu 2 SeC is the hardest, while Lu 2 SeC is the most electrically conductive, the Lu2PC is the most thermally conductive and Lu 2 AuC is the least conductive. [ABSTRACT FROM AUTHOR]

Understanding the oxygen‐redox reactions within Mn‐rich layered cathode materials is an important strategy to improve the capacity of sodium‐ion batteries (SIBs) while satisfying the demand for low cost and the use of abundant resources. Nonetheless, the P2‐type Nay[AxMn1‐x]O2 compositions (where A = electro‐inactive elements) exhibit poor capacity retention and low operation voltage along with a broad voltage hysteresis. In addition, Nay[TMxMn1‐x]O2 (where TM = transition metal) still suffers from low capacity in the absence of anion redox activity. This investigation introduces Li, Mg, and Ni into the P2‐layered NaxMnO2 matrix to explore diverse compositional dynamics engineered by density functional theory and ab initio molecular dynamics. The P2‐Na0.7[Li0.1Mg0.05Ni0.15Mn0.7]O2 configuration is optimized, exhibiting enhanced structural and electrochemical stabilities. Operando X‐ray diffraction analyses affirm the preservation of the P2 structure throughout de/sodiation, and comprehensive structural analyses unraveled the complex charge‐compensation mechanisms facilitated by Ni2+/Ni4+, Mn3+/Mn4+, and O2−/(O2)n− redox pairs. Neutron diffraction and nuclear magnetic resonance techniques elucidate the Li migration phenomena within the TM and sodium layers. This research underscores the pivotal role of Li, Mg, and Ni co‐doping in the development of cathode materials, paving the way for SIBs with enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

Scaffold-guided bone regeneration (SGBR) is a rapidly developing field that aims to address the clinical challenges in reconstructive surgery. Combining ceramics with biodegradable polymers offers a wide range of physico-chemical properties, but their mechanical properties are far from the expectations. Nature offers examples of mineralized materials with excellent mechanical properties. This can be attributed to their unique architecture featuring soft polymeric interfaces that deflect propagating cracks. The present article depicts the role of soft interfaces on bone toughness, the governing equations of cracks propagating at interfaces, and provide guidelines for the design of medical grade composites for SGBR. [ABSTRACT FROM AUTHOR]

Copyright of China Surfactant Detergent & Cosmetics (2097-2806) is the property of China Surfactant Detergent & Cosmetics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Autogenous bone grafting has long been considered the gold standard for treating critical bone defects. However, its use is plagued by numerous drawbacks, such as limited supply, donor site morbidity, and restricted use for giant-sized defects. For this reason, there is an increasing need for effective bone substitutes to treat these defects. Mollusk nacre is a natural structure with outstanding mechanical property due to its notable “brick-and-mortar” architecture. Inspired by the nacre architecture, our team designed and fabricated a nacre-mimetic cerium-doped layered nano-hydroxyapatite/chitosan layered composite scaffold (CeHA/CS). Hydroxyapatite can provide a certain strength to the material like a brick. And as a polymer material, chitosan can slow down the force when the material is impacted, like an adhesive. As seen in natural nacre, the combination of these inorganic and organic components results in remarkable tensile strength and fracture toughness. Cerium ions have been demonstrated exceptional anti-osteoclastogenesis capabilities. Our scaffold featured a distinct layered HA/CS composite structure with intervals ranging from 50 to 200 μm, which provided a conducive environment for human bone marrow mesenchymal stem cell (hBMSC) adhesion and proliferation, allowing for in situ growth of newly formed bone tissue. In vitro, Western-blot and qPCR analyses showed that the CeHA/CS layered composite scaffolds significantly promoted the osteogenic process by upregulating the expressions of osteogenic-related genes such as RUNX2, OCN, and COL1, while inhibiting osteoclast differentiation, as indicated by reduced TRAP-positive osteoclasts and decreased bone resorption. In vivo, calvarial defects in rats demonstrated that the layered CeHA/CS scaffolds significantly accelerated bone regeneration at the defect site, and immunofluorescence indicated a lowered RANKL/OPG ratio. Overall, our results demonstrate that CeHA/CS scaffolds offer a promising platform for bone regeneration in critical defect management, as they promote osteogenesis and inhibit osteoclast activation.

In this work, the two‐step modification process is designed to improve the dispersity and interfacial interaction of lamellar aluminum phosphate (LAP) nanoparticles (NPs). The LAP NPs are successfully modified by maleimidopropyl triethoxysilane (MPTES). LAP/blend bismaleimide (BBMI) composites were prepared by mechanical blending process. Among them, the flexural strength of the modified LAP/BBMI composites were significantly enhanced with more than 148.2 MPa, the characteristic heat resistance temperature (T40) was improved by 11.7°C, and the carbon residue rate (Y600) also increased by 8.8%. Specifically, the dielectric constant of the modified LAP/BBMI composites only display a slight enhancement, but the dielectric loss is reduced to lower than 0.015. The results are helpful to potentially apply in the fields of electromagnetic and wave transparent materials. [ABSTRACT FROM AUTHOR]

Novel structured Na-doped MoS2 nanosheets were developed in situ on Ni foam through a more accessible two-step hydrothermal technique. Benefiting from the synergistic reactions of the superior capacitance of Na-doped MoS2 nanosheet, the superior electrical kinetics of Na-doped, and the porous nanostructure of the composites, the designed Na-doped MoS2 nanosheet composites electrode achieves notable electrochemical activity. The material's structural properties investigate using an X-ray photoelectron spectroscope analyzer, X-ray powder diffractions, scanning electron microscope, and transmission electron microscope. The electrochemical activity of the designed electrodes was executed using cyclic voltammograms, galvanostatic charge/discharges, and electrochemical impedance spectroscopy. Compared to the pure MoS2 electrode, the novel architecture Na-doped MoS2 nanosheet deremonstrates a higher specific capacity of 374.3 C g−1 at 1 A g−1. In addition, it achieves notable cycling stability performance and retains 87.4% capacity over 5,000 long cycles at 3 A g−1. These notable results reveal that the uniquely designed Na-doped MoS2 nanosheet displays superior electrochemical consequences and higher potential as nanomaterials for supercapacitors. [ABSTRACT FROM AUTHOR]

Bitcoin becomes the focus of scientific research in the modern era. Blockchain is the underlying technology of Bitcoin because of its decentralization, transparency, trust-less, and immutability features. However, blockchain can be considered the cause of Bitcoin scalability issues, especially storage. Nodes in the Bitcoin network need to store the full blockchain to validate transactions. Over time, the blockchain size will be bulky. So, the full nodes will prefer to leave the network. This leads to the blockchain being centralized and trusted, and the security will be adversely affected. This paper proposes a Stateful Layered Chain Model based on storing accounts' balances to reduce the Bitcoin blockchain size. This model changes the structure of the traditional blockchain from blocks to layers. The experimental results demonstrated that the proposed model reduces the blockchain size by about 50.6 %. Implicitly, the transaction throughput can also be doubled. [JJCIT 2023; 9(2.000): 137-153]

Autogenous bone grafting has long been considered the gold standard for treating critical bone defects. However, its use is plagued by numerous drawbacks, such as limited supply, donor site morbidity, and restricted use for giant-sized defects. For this reason, there is an increasing need for effective bone substitutes to treat these defects. Mollusk nacre is a natural structure with outstanding mechanical property due to its notable "brick-and-mortar" architecture. Inspired by the nacre architecture, our team designed and fabricated a nacre-mimetic cerium-doped layered nano-hydroxyapatite/chitosan layered composite scaffold (CeHA/CS). Hydroxyapatite can provide a certain strength to the material like a brick. And as a polymer material, chitosan can slow down the force when the material is impacted, like an adhesive. As seen in natural nacre, the combination of these inorganic and organic components results in remarkable tensile strength and fracture toughness. Cerium ions have been demonstrated exceptional anti-osteoclastogenesis capabilities. Our scaffold featured a distinct layered HA/CS composite structure with intervals ranging from 50 to 200 μm, which provided a conducive environment for human bone marrow mesenchymal stem cell (hBMSC) adhesion and proliferation, allowing for in situ growth of newly formed bone tissue. In vitro, Western-blot and qPCR analyses showed that the CeHA/CS layered composite scaffolds significantly promoted the osteogenic process by upregulating the expressions of osteogenic-related genes such as RUNX2, OCN, and COL1, while inhibiting osteoclast differentiation, as indicated by reduced TRAP-positive osteoclasts and decreased bone resorption. In vivo, calvarial defects in rats demonstrated that the layered CeHA/CS scaffolds significantly accelerated bone regeneration at the defect site, and immunofluorescence indicated a lowered RANKL/OPG ratio. Overall, our results demonstrate that CeHA/CS scaffolds offer a promising platform for bone regeneration in critical defect management, as they promote osteogenesis and inhibit osteoclast activation. [ABSTRACT FROM AUTHOR]

Copyright of Buletinul AGIR is the property of Asociatia Generala a Inginerilor din Romania and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Jordanian Journal of Computers & Information Technology is the property of Jordanian Journal of Computers & Information Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the mechanical properties and failure characteristics of layered shale in New Yan'an Tunnel and analyze the influence of different inclination angles of bedding plane on rock mechanical parameters. Laboratory uniaxial compression, triaxial compression and Brazil splitting tests and numerical uniaxial compression and triaxial compression tests under different bedding angles were carried out. The laboratory test analysis show that the peak intensity first decreases and then increases with the increase of inclination angle. The compressive strength shows a U-shaped trend, the elastic modulus changes in a “V” shape. And through a large number of numerical simulation tests to expand the scope of laboratory tests and the relationships between compressive strength and elastic modulus with dip angle were fitted respectively. The increase of confining pressure weakens shale anisotropy, but the degree of weakening decreases with the increasing of confining pressure. The strength of laminated shale is weakened by cohesion much more than internal friction angle. The tensile strength decreases with the increase of inclination angle. The failure modes of layered shale are different with different inclination angles, under the condition of uniaxial compression, tensile failure occurs for 0°, shear slip failure along the bedding plane controlled by the weak plane occurs at 30° ~ 60°, cleavage tensile failure occurs at 90°. Under triaxial compression, the shale specimens with different bedding plane inclinations mainly undergo shear failure. [ABSTRACT FROM AUTHOR]

Single-phase three-dimensional vanadium oxide (V4O9) was synthesized by reduction of V2O5 using a gas stream of ammonia/argon (NH3/Ar). The as-synthesized oxide, prepared by this simple gas reduction method was subsequently electrochemically transformed into a disordered rock salt type-“Li3.7V4O9” phase while cycling over the voltage window 3.5 to 1.8 V versus Li. The Li-deficient phase delivers an initial reversible capacity of ∼260 mAhg−1 at an average voltage of 2.5 V vs. Li+/Li0. Further cycling to 50 cycles yields a steady 225 mAhg−1. Ex situ X-ray diffraction studies confirmed that (de) intercalation phenomena follows a solid-solution electrochemical reaction mechanism. As demonstrated, the reversibility and capacity utilization of this V4O9 is found to be superior to battery grade, micron-sized V2O5 cathodes in lithium cells.

As the demand for high-performance hydrophones for marine communication systems grows, this paper develops a high-frequency unfilled layered symmetrical piezoelectric material with high effective electromechanical coupling coefficient. The k t vibration mode of piezoelectric material is converted into k 33 vibration mode of the piezoelectric pillar to improve the effective electromechanical coupling coefficient of the material. The material is determined by the equivalent circuit method and ANSYS finite element simulation method. Test results show that the resonant frequency is 117.8 kHz and the effective electromechanical coupling coefficient is 0.67, which shows that the developed material has a good electromechanical conversion performance. [ABSTRACT FROM AUTHOR]

In view of the problems of poor stope operation safety, serious mining loss and dilution, and low production efficiency when the shallow hole shrinkage method is used for steeply inclined medium-thick ore bodies, in the case study of mining the steeply inclined medium-thick ore body in the Jiuzhanggou mining area of Songxian Shanjin Mining Co., Ltd., by comparing the advantages and disadvantages of various mining schemes, and applying the fuzzy mathematics method and the unascertained measurement theory to optimize the selection, the mining method of double-mining combining upward and horizontal layered filling in the outside-vein raise is determined as the best mining plan. An industrial test was carried out in Stope 4150529 on the Level 15 of the Jiuzhanggou mining area. A total of 23 750 t of ores was mined within one year of the test, and the mining loss rate was reduced to 4.0 %,and the ore dilution rate is reduced to 5.8 %.Compared with the shallow hole shrinkage method used in the early mines, the profit increased by 68.05 yuan/t. The economic benefits are significant. The study can be used as a reference for similar mines. [ABSTRACT FROM AUTHOR]

Current state-of-the-art ultraviolet (UV) photodetectors are extensively used in applications ranging from industrial to biomedical science. As a result, there have been consistent efforts to improve their efficiency and to address challenges related to sensitivity and spectral selectivity. Two-dimensional (2D) materials, with their distinct properties, offer a promising solution due to their excellent UV detection characteristics. Additionally, their atomic scalability and CMOS compatibility enable easy integration with flexible platforms and current technologies. The exceptional optoelectronic characteristics, strong light-matter interaction, and quantum confinement in certain 2D materials have led to extensive investigations into 2D material-based UV photodetectors. This review provides a broad overview of the mechanisms of photodetection, various device configurations, and the current progress in both layered and non-layered 2D UV photodetectors. Finally, strategies for improving UV photodetection properties are discussed, along with a future outlook on the integration of 2D UV detectors into commercial platforms. [Display omitted] [ABSTRACT FROM AUTHOR]

The current need to accelerate the adoption of photovoltaic (PV) systems has increased the need to explore new nanomaterials that can harvest and convert solar energy into electricity. Transition metal dichalcogenides (TMDCs) are good candidates because of their tunable physical and chemical properties. CuCrS2 has shown good electrical and thermoelectrical properties; however, its optical and photoconductivity properties remain unexplored. In this study, we synthesized CuCrS2 nanosheets with average dimensions of 43.6 ± 6.7 nm in length and 25.6 ± 4.1 nm in width using a heat-up synthesis approach and fabricated films by the spray-coating method to probe their photoresponse. This method yielded CuCrS2 nanosheets with an optical bandgap of ~1.21 eV. The fabricated film had an average thickness of ~570 nm, exhibiting a net current conversion efficiency of ~11.3%. These results demonstrate the potential use of CuCrS2 as an absorber layer in solar cells. [ABSTRACT FROM AUTHOR]

The exploration of gas pressure and its distribution in landfills is a principal concern for the design and management of municipal solid waste (MSW) landfills. A one-dimensional analytical model was proposed to simulate a vertical gas flow in a landfill with layered MSWs. The transient analytical solution was obtained by the method of superposition and eigenfunction expansion and verified by a semi-analytical solution and numerical simulation. According to the results of a parametric analysis by the transient analytical solution, a vertical gas flow in landfills can be simplified to a quasi-steady-state flow. A quasi-steady-state analytical solution for simulating a vertical gas flow in a landfill with layered MSW is proposed. The quasi-steady-state analytical solution showed good agreement with the transient solution. Both temporal and spatial variations of the gas generation rate in MSW landfills were considered in the transient and quasi-steady-state analytical methods. A comparison between the proposed quasi-steady-state solution and the previously described steady-state solution showed that using the average gas generation rate or the gas generation rate corresponding to the average age of the MSW layer in the steady-state solution resulted in an error in the estimation of the gas pressure in landfills. The proposed solutions are reliable and can provide a reference for the design, management, and subsequent restoration of landfills. [ABSTRACT FROM AUTHOR]

Uniform surface wrinkling has attracted broad attention with its potential applications in stretchable electronics, optics and templating. However, engineering wrinkles with controlled defects still needs to be explored due to the lack of evaluation of fabrication parameters. Taking the advantage of orthogonal experiment, the influence of oxygen plasma treatment power, time, pressure and pre-strain ratio was explored for controlling the crack formation during Polydimethylsiloxane (PDMS) wrinkling. Among, plasma power has the greatest contribution on crack density, while pressure and time have relatively few influence, providing an insight for fabricating crack-free surface micro- and nanostructures. [ABSTRACT FROM AUTHOR]

Multilayer metal composite materials are used in the chemical industry, particularly nuclear power engineering, and enable to increase the robustness and durability of steel structures while reducing their metal consumption. These materials are made of stainless steel, alternating with commercial quality steels, and have increased corrosion resistance, several times greater than the resistance of stainless steel in the material structure. In this work, the structure formation of the transition layer of a layered metal composite material obtained via explosion welding was studied through the transmission electron microscopy method. A high concentration of dislocations in the transition layer was established. After the blast exposition, the material retained its crystalline structure and acquired a directional texture. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) SnO is a p-type semiconductor that has received research and industrial attention for device-grade applications due to its bipolar conductivity and transparent semiconductor nature. The first-principles investigations based on the generalized gradient approximation (GGA) level of theory often failed to accurately model its structure due to interlayer Van der Waals interactions. This study is carried out to calculate structural and electronic properties of bulk and layered structures of SnO using dispersion correction scheme DFT+D3 with GGA-PBE to deal with the interactions which revealed good agreement of the results with reported data. The material in three-dimensional bulk happened to be an indirect gap semiconductor with a band gap of 0.6 eV which is increased to 2.85 eV for a two-dimensional monolayer structure. The detailed analysis of the properties demonstrated that the SnO monolayer is a promising candidate for future optoelectronics and spintronics devices, especially thin film transistors. [ABSTRACT FROM AUTHOR]

Last years’ changes in the legislation on forest management in virgin, quasi-virgin and natural forests and the constant increase of the scientificfic and the public interest in the silviculture of virgin forest ecosystems have led to the identification of such forests and the natural monuments of virgin forests organization throughout Ukraine. The main part of this research and legislative work done within the framework of the of the World Wide Fund for Nature in Ukraine pro-jects, according to which about 100 thousand hectares of such forests have al-ready been identified, but these data are constantly updated. It was found that in these forests with 11 main species prevails Common beech (58 5) and Norway spruce (33 %), but Mountain pine (5 %) and Silver fir (3 %) are well represented too. These forests growth in 91 types of forest and biggest area have next: wet pure beech mesotrophic (18%) and megatrophic (18%) types, wet pure spruce mesotrophic (13%) and cedar pine-spruce oligotrophic (6%) types, wet beech-fir-spruce (6%) and spruce-fir-beech (5%) mesotrophic. Such significant diversity of forest types and types of forest stands in virgin, quasi-virgin and natural forests and the need to control the level of anthropogenic interference in their functioning determined the development of a new method of virgin forest monitoring based on the results of their scientific research and on the approved methods of forest monitoring and identification of primeval forests. The developed method tested in 2020 at six permanent plots in the Ukrainian Carpathians with the assistance of the World Wide Fund for Nature in Ukraine. Good conditions of these forests revealed (the best conditions had the spruce vir-gin forest and the worst – in the spruce-beech-fir quasi-virgin forest) and these forests had an insignificant anthropogenic impact (mainly infrastructure and rec-reation). For example, spruce virgin forest has average forest parameters, but the best in-dicators of condition: a low number of trees (especially in the second and third layers), average wood volume and undergrowth number, one of the largest vol-ume of the lying deadwood, the highest vitality, functionality and marketability of trees, the best position and the longest crown of trees, insignificant anthropo-genic impact (old path up to 1 m wide). Spruce-beech-fir quasi-virgin forest has other characteristics: a high number of trees, the largest wood volume and the most complex structure, one of the largest volume of the lying deadwood and the smallest number of undergrowth, one of the highest vitality of trees, insignificant, albeit diverse, anthropogenic impact (cutting of trees, dragging way up to 0.9 m wide, pollution by plastic). Beech quasi-virgin forest has the biggest stand indica-tors (diameter and height), the smallest number of trees and volume of the lying deadwood, one of the lowest wood volume, the largest number of undergrowth, low vitality and the worst marketability of trees, insignificant anthropogenic im-pact (cutting of lying trees, old dragging way). The necessity of annual monitoring of virgin forests from scientific and sozologi-cal positions to control their development and anthropogenic influence on these ecosystems has been substantiated.

Oxygen‐redox‐based cathode materials for sodium‐ion batteries (SIBs) have attracted considerable attention in recent years owing to the possibility of delivering additional capacity in the high‐voltage region. However, they still suffer from not only fast capacity fading but also poor rate capability. Herein, P2‐Na0.75[Li0.15Ni0.15Mn0.7]O2 is introduced, an oxygen‐redox‐based layered oxide cathode material for SIBs. The effect of Ni doping on the electrochemical performance is investigated by comparison with Ni‐free P2‐Na0.67[Li0.22Mn0.78]O2. The Na0.75[Li0.15Ni0.15Mn0.7]O2 delivers a specific capacity of ≈160 mAh g−1 in the voltage region of 1.5–4.6 V at 0.1 C in Na cells. Combined experiments (galvanostatic cycling, neutron powder diffraction, X‐ray absorption spectroscopy, X‐ray photoelectron spectroscopy, and nuclear magnetic resonance (7Li NMR)) and theoretical studies (density functional theory calculations) confirm that Ni substitution not only increases the operating voltage and decreases voltage hysteresis but also improves the cycling stability by reducing Li migration from transition metal to Na layers. This research demonstrates the effect of Li and Ni co‐doping in P2‐type layered materials and suggests a new strategy of using Mn‐rich cathode materials via oxygen redox with optimization of doping elements for SIBs. [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sodium-ion batteries are widely studied due to their abundant sodium resources, widespread distribution, and environmental friendliness. However, due to the large radius of sodium ions, during the charge and discharge process, the cycling performance and rate performance deteriorated seriously, which severely limited the commercial application of sodium-ion batteries. The positive electrode material plays a vital role in the performance of sodium-ion batteries. NaxFeO2 and NaxMnO2 series positive electrode materials showed high theoretical specific capacity and environmentally friendly. They are considered to be potential positive electrode materials for sodium-ion batteries. This article summarizes the research progress of NaxFeO2 and NaxMnO2 series cathode materials in recent years, and discusses the problems and development directions of cathode materials for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Nanoscale morphology has a direct impact on the performance of materials for electrochemical energy storage. Despite this importance, little is known about the evolution of primary particle morphology nor its effect on chemical pathways during synthesis. In this study, operando characterization is combined with atomic‐scale and continuum simulations to clarify the relationship between morphology of cathode primary particles and their lithiation during calcination of LiNi0.8Mn0.1Co0.1O2 (NMC‐811). This combined approach reveals a key role for surface oxygen adsorption in facilitating the lithiation reaction by promoting metal diffusion and oxidation, and simultaneously providing surface sites for lithium insertion. Furthermore, oxygen surface termination is shown to increase the activation energy for sintering, leading to smaller primary particle sizes at intermediate temperatures. Smaller particles provide both shorter diffusion lengths for lithium incorporation and increased surface site density for lithium insertion. These insights provide a foundation for more tailored syntheses of cathode materials with optimized performance characteristics. [ABSTRACT FROM AUTHOR]

There is a growing appreciation for the role of surface reactivity and subsequent reconstruction affecting the performance of high-voltage, high-capacity Li-ion cathode materials. In particular, the promising Li-excess materials are known to exhibit significant vulnerability toward oxygen release, which can cause surface densification and impede Li intercalation. Here we focus on the end member, Li2MnO3, as a Li-excess, Mn-rich representative of this class of materials and systematically elucidate all possible stoichiometric low Miller index surfaces with various cation ordering on each surface. We apply surface cation reconstruction rules that depend on the local environment, including target Mn-Li site exchanges, and optimize the resulting surface Li configurations using metadynamics. The equilibrium Wulff shape shows dominant (001), (010) surface facets, and almost all facets exhibit favorable Mn reconstruction. Most importantly, we find that while all equilibrium LixMnO3 surfaces become unstable toward oxygen release for x < 1.7, some facets are consistently more resistant than others which may provide a design metric for more stable particle morphologies and enhanced surface oxygen retention.

Traditional restoration and rehabilitation work of flat timber ceilings at historical Islamic buildings in Cairo generally require the dismantling of most of their timber parts (i.e. timber planks, secondary beams, etc.) to expose the timber main beams and conduct the work. Hence, these parts are liable to damage and lose during the dismantling that requires time, money and effort to achieve. Hence, the author conducted this study to overcome the dismantling work and propose effective strengthening techniques for the timber beams utilizing two-layered composite system. This paper reported the limited application of the layered system in the construction of the historical timber beams in Cairo. It studied a number of innovative strengthening proposals of the timber beams from their upper-side merely while leaving the exposed bottom surface intact, apart from its indispensable shoring. Hence, a small experimental and a wide comparative analytical investigation of the strengthening proposals utilizing two-layered composite system are conducted. Several 2D Finite Element numerical models using well-known software were conducted. The modelling techniques of various interfacial conditions of the two-layered beams are established and evaluation of the strengthening proposals is conducted. Finally, conclusions and recommendations are derived.

In this paper, a new longitudinal and lateral coordinated control algorithm for the intelligent vehicle (IV) is proposed for the problem of unbalance of tracking accuracy and vehicle stability during path tracking process. This work proposes a novel algorithm that adopts hierarchical control architecture and local linearization of the nonlinear path tracking model, establishes the objective function by tracking performance and driving performance in the tracking process, and designs the upper optimal controller. Following the theory of fuzzy proportional-derivative control method, a low-speed tracking controller is designed to track the desired speed. Simulations and the hardware-in-the-loop test are utilized to verify the effectiveness of the designed path tracking control algorithm. Results show that, unlike the traditional fixed-speed tracking control method, the proposed vertical and horizontal coordinated control algorithm can guarantee the vehicle's tracking performance at different speeds and improve its form stability. The improved effect is evident even at high speed.

2D heterostructures offer new opportunities for harnessing a wider range of the solar spectrum in high-performance photovoltaic devices. Here, we explore a type-II p–n heterojunction, by exploiting air-stable tellurene (Te) in combination with MoS2, to study its charge transfer for photovoltaic applications. The charge transfer of MoS2/Te heterojunction is confirmed by photoluminescence spectroscopy, Raman spectroscopy and Kelvin probe force microscopy. The exciton binding energy for MoS2/Te heterojunction is estimated to be around 10 meV, which is much lower than that for monolayer MoS2. This strategy can be exploited to develop next-generation intrinsically ultrathin light-harvesting devices. [ABSTRACT FROM AUTHOR]

Nanoindentation pop-ins in composite source shale were characterized as Type I and Type II, where the slopes on load–displacement (p–h) curves are defined as Δp/Δh = 0 or Δp/Δh > 0, respectively. Type I were associated with sudden instantaneous failure as elastic perfectly plastic "Coulomb-type" and sudden grain dislodging, while Type II were related to shear band progressive failure and/or grain sliding or progressive pile-up. Pop-ins were primarily observed when indenting perpendicular to the shale layers. Estimating magnitudes of pop-in energy dissipation varied widely with shale matrix phases. Meanwhile, Type III pop-ins defined by Δp/Δh < 0, were never observed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The exploration of gas pressure and its distribution in landfills is a principal concern for the design and management of municipal solid waste (MSW) landfills. A one-dimensional analytical model was proposed to simulate a vertical gas flow in a landfill with layered MSWs. The transient analytical solution was obtained by the method of superposition and eigenfunction expansion and verified by a semi-analytical solution and numerical simulation. According to the results of a parametric analysis by the transient analytical solution, a vertical gas flow in landfills can be simplified to a quasi-steady-state flow. A quasi-steady-state analytical solution for simulating a vertical gas flow in a landfill with layered MSW is proposed. The quasi-steady-state analytical solution showed good agreement with the transient solution. Both temporal and spatial variations of the gas generation rate in MSW landfills were considered in the transient and quasi-steady-state analytical methods. A comparison between the proposed quasi-steady-state solution and the previously described steady-state solution showed that using the average gas generation rate or the gas generation rate corresponding to the average age of the MSW layer in the steady-state solution resulted in an error in the estimation of the gas pressure in landfills. The proposed solutions are reliable and can provide a reference for the design, management, and subsequent restoration of landfills.

In this article, a novel low profile wideband highly directive gradient refractive index (GRIN) metasurface (MS) lens is designed to improve the gain of the X-band waveguide-based RF sensor system for the microwave imaging application. The proposed GRIN MS lens consists of several layers comprising the core layers at the centre and the impedance matching layers around both sides of the core layers. The core layers and the impedance matching layers of the proposed lens are based on a novel three-layer unit cell, wherein a single rectangular ring and two C-shaped strips are printed on both sides of the middle layer. The cross-sectional dimensions of the proposed unit cell varying across the lens aperture to realize the refractive index profile gradually varying from 1.5 at both edges to 7 at the centre. After designing the GRIN MS lens, an attractive microwave technique using a combination of piecewise synthetic aperture radar (PW-SAR) scheme and a time-domain algorithm for imaging of layered media is proposed. The use of a noniterative time-domain technique in the present situation basically helps to retrieve the electrical and physical properties of each layer, which are inherently required for the SAR algorithm to obtain a focused image of the target object buried in the layered media. The experimental results show that the integration of the proposed GRIN MS lens with the RF waveguide sensor improves the overall gain by the maximum value of 10.5 dB, thereby enhancing the spatial resolution of the target object in a layered media using the modified SAR imaging scheme. [ABSTRACT FROM AUTHOR]

This study aims to investigate hydrofracturing in double-layered soil through theoretical and experimental analysis, as multilayered soils where the difference in mechanical properties exists are generally encountered in practical engineering. First, an analytical solution for fracturing pressure in two different concentric regions of soil was presented based on the cavity expansion theory. Then, several triaxial hydraulic fracturing tests were carried out to validate the analytical solution. The comparison between the experimental and analytical results indicates the remarkable accuracy of the derived formula, and the following conclusions were also obtained. First, there is a linear relationship between the fracturing pressure and confining pressure in concentric double-layered cohesive soil. Second, when the internal-layer soil is softer than the external-layer soil, the presence of internal soil on the fracturing pressure approximately brings the weakening effect, and the greater strength distinction between the two layers, the greater the weakening effect. Third, when the internal-layer soil is harder than the external-layer soil, the existence of the internal-layer soil has a strengthening effect on the fracturing pressure regardless of the proportion of internal-layer soil. Moreover, the influence of strength distinction between the two layers on the fracturing pressure is significant when the proportion of internal-layer soil is less than half, while it's limited when the proportion is more than half. The proposed solution is potentially useful for geotechnical problems involving aspects of cohesive soil layering in a composite formation. [ABSTRACT FROM AUTHOR]

In this study, layered-structured Al 2 O 3 -based composites containing WC-Co, TiC, and MgO additives were prepared using hot-pressing sintering. The best comprehensive mechanical characteristics were acquired for the sample with a layer number (N LN) of 7 and thickness ratio (η TR) of 6. Its composite exhibited a fracture toughness of 8.5 and 8.4 MPa m1/2 in the X and Z directions, respectively. Analysis of the micro characteristics of the fracture surfaces of the Al 2 O 3 -TiC-WC-Co layered composites revealed a significant enhancement in the bending strength, which could be attributed to the mixed fracture modes in the composite, including intergranular and trans -granular modes. As the displacement increased, first, the bending stress of all the composites increased gradually, after which all the samples showed abrupt elevation in stress. The enhancement in the damage resistance of Al 2 O 3 -TiC-WC-Co layered composites could be attributed to the microscopic and macroscopic crack deflection, bridging, and partial surface bonding that occurred in the layers. Finally, a new theoretical perspective was employed to discuss the mechanism of the effect of the layered structure on the toughness of the composites. [ABSTRACT FROM AUTHOR]