Mechanical Stability Research Articles

MBRD Prototype Cold Tests: Mechanical Stability and Performances

MBRD Prototype Cold Tests: Mechanical Stability and Performances

First-principles calculations to investigate Structural, Electronic, mechanical and Optical Properties of SrAlO3 Compound

In this study, density functional theory calculations were used to investigate the structural, electronic, mechanical, and optical properties of SrAlO3 perovskites. Calculations were performed using WEIN2K with the Generalized Gradient Approximation (GGA) and modified Becke-Johnson (MBJ) methods. The present compound shows large band gap around 5.67 eV for GGA method and 6.70 eV for MBJ method. The band structure (BS) and partial density of states (PDOS) reveal the predominant involvement of the oxygen-p orbital in the valence band, while the Al and Sr-s, p and d orbital contribute significantly to the conduction band, that play a significant role in determining the electronic and optical properties. Using the GGA and MBJ methods, the optical properties of SrAlO3 have been determined in terms of optical conductivity, dielectric constant, absorption coefficient, energy loss, optical reflectivity, and refractive index. It has been noted that the features present in the optical absorption spectra obtained experimentally match those of the simulated spectra featuring an oxygen vacancy. We use elastic constants to describe a material's mechanical properties. Under normal conditions, these materials' elastic constants demonstrate their mechanical stability. We meticulously determined the elastic constants by graphing the directional variations of compressibility, Young's modulus, and shear modulus. Our findings indicate that these chemicals have high elastic constants. Furthermore, we collect and interpret the phonon spectra. Complete phonon dispersion simulations validate the dynamic stability of the SrAlO3.

Highly Transmittance, Mechanical, Thermally Stable Silver Nanowires Network Using ZnO Nanoparticles.

This research addresses challenges with silver nanowires (Ag NWs) as transparent conductive electrodes (TCEs) and heaters in commercial devices. Here, zinc oxide nanoparticles (ZnO NPs) are first reported as a protective layer for Ag NWs. Multi-physics simulations confirm enhanced thermal stability due to improved heat dissipation, temperature distribution, and thermal conductivity from ZnO. When Ag NWs are surrounded by air, heat transfers mainly through convection and radiation because of air's low conduction coefficient. Encasing Ag NWs in ZnO enhances heat transfer to the ZnO surface, accelerating cooling and dissipating more heat into the atmosphere via convection. The results show composite's efficiency in the Joule effect, maintaining a consistent temperature of 78°C for 700s after 500 bending cycles, a significant improvement over Ag NWs operating for only 5s at 80°C. Additionally, the composite film exhibited exceptional performance, including a sheet resistance of 9.8Ωsq-1 and an optical transmittance of 96.96 %, outperforming Ag NWs, which have a sheet resistance of 12Ωsq-1 and a transmittance of 94.11%. The combination of enhanced electrical, thermal, and mechanical stability, along with impressive optical properties, makes Ag NWs/ZnO NPs a promising candidate for transparent conductive electrode materials in various applications.

Core-shell magnetic covalent organic polymer nanocomposites as an adsorbent for the extraction of flavonoids.

A novel 3D magnetic nanocompositematerialbased on covalent organic polymers was successfully synthesized and utilized as an efficient sorbent for magnetic solid-phase extraction. It exhibited a regular core-shell structure, large specific surface area, superior stability, and paramagnetism. To evaluate its extraction efficiency, six flavonoids were tested, demonstrating maximum adsorption capacities ranging from 90 to 218mg/g. Additionally, the material exhibited remarkable reusability and mechanical stability, maintaining its original state over eight cycles with consistent recovery. An analytical strategy combining magnetic solid-phase extraction with high performance liquid chromatography and tandem mass spectrometry was developed for the determination of flavonoids in orange, honey, soybean, and Dioscorea bulbifera L. samples. The low limits of detection (0.01-0.1ng/mL) and limits ofquantification (0.05-0.5ng/mL), as well as satisfactory recovery (80.4-114.8%), were obtained. The linear range started from the limits of quantification to 500ng/mL with R2 ≥ 0.9929. These results suggest that the prepared adsorbent possesses excellent adsorption capabilities for flavonoids, highlighting its significant potential for detecting these compounds in complex sample matrices.

Buoyancy-Assisted Fabrication of Liquid Diode: Janus Nanofibrous Membrane for Efficient Wastewater Treatment.

The pressing need for effective methods to separate oil and water in oily wastewater has spurred the development of innovative solutions. This work presents the creation and evaluation of a Janus nanofibrous membrane, also known as the Liquid Diode, developed using electrospinning (e-spinning) and buoyancy-assisted hydrothermal techniques. The membrane features a unique structure: one side is composed of PVDF nanofibers embedded with a GO/TiO2 composite, exhibiting in-air superhydrophobic and superoleophilic properties, while the reverse side consists of PVDF nanofibers with a ZnO nanorod array, demonstrating in-air superhydrophilic and underwater (UW) superoleophobic properties. This distinct asymmetric wettability enables the membrane to effectively separate both water-in-oil (w-in-o) and oil-in-water (o-in-w) emulsions, achieving an impressive liquid flux and separation efficiency (SEff). The in-air superhydrophobic side of the Janus nanofibrous membrane achieves a maximum oil flux (Fo) of 3506 ± 250 L m-2 h-1, while the in-air superhydrophilic side achieves a maximum water flux (Fw) of 1837 ± 150 L m-2 h-1, with SEff exceeding 98% for both sides. Furthermore, the Janus nanofibrous membrane maintained reliable mechanical stability after 10 cycles of sandpaper abrasion test and demonstrated excellent chemical stability when subjected to acidic, alkaline, cold water and hot water conditions for 24 h. These properties, combined with its ability in breaking down of organic contaminants (98% ± 2% in 210 min) and pharmaceutical contaminants (97% ± 2% in 210 min) under visible light, highlight its photocatalytic potential. Additionally, the membrane's antifouling and antibacterial properties suggest long-term and sustainable use in wastewater treatment applications. The synergistic combination of these superior properties positions the Janus nanofibrous membrane as a promising solution for addressing complex challenges in wastewater treatment and environmental remediation.

Dual-gradient Concentration Distribution in Sb-Cu Alloy Nanoarrays for Robust Sodium-ionStorage.

Alloy-type materials are attractive for anodes in sodium-ion batteries (SIBs) owing to their high theoretical capacities and overall performance. However, the accumulation of stress/strain during repeated cycling results in electrode pulverization, leading to rapid capacity decay and eventual disintegration, thus hindering their practical applications. Herein, we report a 3D coral-like Sb-Cu alloy nanoarray with gradient distribution of both elements. The array features a Sb-rich bottom and a Cu-rich top with increasing Sb and decreasing Cu concentrations from top to bottom. The former is the active component that provides the high capacity, whereas the latter serves as an inert additive that acts against volume variation. The gradual transition in composition within the electrode introduces a ladder-type volume expansion effect, facilitating a smooth distribution and effective release of stress, thereby ensuring the wanted mechanical stability and structural integrity. The as-developed nanoarray affords a high reversible capacity (460 mAh g-1 at 0.5 C), stable cycling (89% retention over 120 cycles at 1.0 C), and superior rate capability (354 mAh g-1 at 10 C). The concentration dual-gradient strategy paves a new pathway of designing alloy-type materials for SIBs.

An enhanced consensus algorithm for blockchain

Consensus plays a crucial role in blockchain technology, with the deleted proof of stake (DPoS) consensus mechanism commonly utilized in both public and hybrid chains. However, the current DPoS mechanism faces challenges such as low node engagement in voting and potential security risks posed by malicious nodes. In response, we propose the DL-DPoS (deep link–delegated proof of stake) mechanism, which builds upon the DPoS framework. The DL-DPoS incorporates the LINK incentive mechanism to encourage inactive nodes to participate in voting and leader selection. Furthermore, a comprehensive credit scoring system based on wealth, performance, and stability is introduced to enhance the security of elected nodes. The verification process is optimized to involve all nodes except the leader node, and mechanisms are in place to handle malicious attacks by degrading or removing offending nodes and redistributing their responsibilities to the LINK group. Performance testing of the DL-DPoS mechanism, conducted through blockchain simulation tests using the GO language, shows a 23% increase in throughput compared to DPoS, with over 95% node participation and improved distribution of rights and equity. These results indicate the enhanced performance, security, and stability of the DL-DPoS consensus mechanism.

Patella Fractures after Total Knee Arthroplasty.

Periprosthetic patella fractures are a rare complication that can lead to severe disability following total knee arthroplasty (TKA). There are several factors that increase the risk of this injury, including patient co-morbidities, anatomic considerations, and surgical technique. With these factors limiting healing ability in the area, periprosthetic patellar fractures can pose a major challenge to treat, with potentially lasting morbidity for affected patients. These fractures can occur at any time following TKA and are classified based on their associated implant stability and disruption of the extensor mechanism using the Ortiguera and Berry classification system. Each of the three types of fractures can be managed in their own unique way; however, outcomes remain poor, and the complication rates remain high regardless of fracture type. This article provides an overview of the current literature and the recommended management of periprosthetic patella fractures.

Mechanically Robust Biopolymer Optical Fibers with Enhanced Performance in the Near-Infrared Region.

Polymer optical fibers (POFs) are lightweight, fatigue-tolerant, and suitable for local area networks, automobiles, aerospace, smart textiles, supercomputers, and servers. However, commercially available POFs are exclusively fabricated using synthetic polymers derived from nonrenewable resources. Recently, attempts have been made to fabricate biocompatible and biopolymeric optical fibers. However, their limitations in mechanical performance, thermal stability, and optical properties foil practical applications in waveguiding. Here, we report a comprehensive study of the preparation of biopolymer optical fibers with tailored mechanical strength, thermal properties, and their short-distance applications. Specifically, we use alginate as one of the key components with methylcelluloses to promote readily scalable wet spinning at ambient conditions to fabricate 21 combinations of composite fibers. The fibers display high maximum strain (up to 58%), Young's modulus (up to 11 GPa), modulus of toughness (up to 63 MJ/m3), and a high strength (up to 195 MPa), depending on the composition and fabrication conditions. The modulus of toughness is comparable to that of glass optical fibers, while the maximum strain is nearly 15 times higher. The mechanically robust fibers with high thermal stability allow rapid humidity, touch sensing, and complex shapes such as serpentine, coil, or twisted structures without losing their light transmission properties. More importantly, the fibers display enhanced optical performance and sensitivity in the near-infrared (NIR) region, making them suitable for advanced biomedical applications. Our work suggests that biobased materials offer innovative solutions to create short-distance optical fibers from fossil fuel-free resources with novel functionalities.

Maleated epoxidized natural rubber grafted cassava starch/silver composite coating for cloth glove: Preparation and physical properties

The green composite was obtained from maleated epoxidized natural rubber (MENR) latex grafted cassava starch (CS) (MNS) and silver nanoparticles (AgNPs) by using a green route process. The immersion of AgNPs in the MNS matrix was checked with UV–visible spectrometer. The SEM was applied to study the morphology of AgNPs particle. The thermal stability of the MNSAg composite increased with increasing AgNPs. The AgNPs well distributed in the MNS matrix. The silver was used to facilitate the facile and fast preparation and to improve the mechanical strength and thermal stability at 420–450 °C of the MNSAg composites. The MNSAg composite containing AgNPs exhibited excellent antibacterial activities against both Escherichia coli and Staphylococcus aureus. Moreover, it showed the high UV absorption. It was used to coat with cloth gloves. The degree of biodegradation of this sample was about 80–90 % after being buried in soil.

Stable zinc anode solid electrolyte interphase via inner Helmholtz plane engineering

The inner Helmholtz plane and thus derived solid-electrolyte interphase (SEI) are crucial interfacial structure to determine the electrochemical stability of Zn-ion battery (ZIB). In this work, we demonstrate that introducing β-cyclodextrins (CD) as anion-receptors into Zn(OTf)2 aqueous electrolyte could significantly optimize the Zn anode SEI structure for achieving stable ZIB. Specifically, β-CD with macrocyclic structure holds appropriate cavity size and charge distribution to encase OTf- anions at the Zn metal surface to form β-CD@OTf- dominated inner Helmholtz structure. Meanwhile, the electrochemically triggered β-CD@OTf- decomposition could in situ convert to the organic-inorganic hybrid SEI (ZnF2/ZnCO3/ZnS‒(C-O-C/*CF/*CF3)), which could efficiently hinder the Zn dendrite growth with maintain the proper SEI mechanical strength stability to guarantee the long-term stability. The thus-derived Zn | |Zn pouch cell (21 cm2 size) with β-CD-containing electrolyte exhibits a cumulative capacity of 6450 mAh−2 cm−2 at conditions of 10 mAh cm−2 high areal capacity. This work gives insights for reaching stable ZIB via electrolyte additive triggered SEI structure regulation.

Adaptive Changes in Longitudinal Arch During Long-distance Running.

This study investigates the biomechanical adaptations of the longitudinal arch (LA) in long-distance runners, focusing on changes in stiffness, angle, and moment during a 60-minute run. Twenty runners participated in this experiment, and were asked to run at a speed of 2.7 m·s-1 for 60 minutes. The kinematic and kinetic data collected at five-minute intervals during running were calculated, including the stiffness of LA in the loading phase (k load ) and the stiffness of LA in the unloading phase (k unload ), the maximum LA moment (M max ), the range of LA angle change (∆θ range ), and the maximum LA angle change (∆θ max ). Foot morphology was also scanned before and after running. Variations of kinematic and kinetic data were analyzed throughout the running activity, as well as variations of foot morphology pre- and post-run. Results showed that there was a significant decrease in k load (p<0.001), coupled with increases in ∆θ range (p=0.002) and ∆θ max (p<0.001), during the first 15 minutes of running, which was followed by a period of mechanical stability. No differences were found in k unload and M max throughout the running process and the foot morphology remained unchanged after running. These results highlight a critical adaptation phase that may be pivotal for improving running economy and performance.

Designing a Robust Ni-P/CeO2 Superhydrophobic Composite Coating for Synergistically Enhanced Corrosion Protection and Friction Reduction Performance.

Superhydrophobic surfaces have received widespread attention for their unique hydrophobicity in metal corrosion protection. However, the shortcomings of mechanical stability and long-term corrosion resistance limit their practical application. In this work, we designed and fabricated an anticorrosive and friction reducing Ni-P/CeO2 superhydrophobic composite (SC) coating on a copper surface. The fabricated coating shows good superhydrophobicity with a water contact angle of up to 154°. The Ni-P support structure and CeO2 nanoparticles form a multilayer micro/nanostructure by electrodeposition, ensuring excellent mechanical stability of the Ni-P/CeO2 SC coating. Electrochemical tests indicate that the coating has excellent corrosion resistance due to the superhydrophobic air film, Ni-P barrier layer, and CeO2 inhibition. Moreover, the friction coefficient of the coating is only 0.11 under dry friction conditions, showing excellent friction-reducing performance, which is attributed to the cooperation of the low adhesion coefficient of superhydrophobic surfaces, the ball-rolling effect of CeO2 nanoparticles, and the self-healing effect of the Ni-P micro/nanostructure. This work provides a novel strategy for designing a robust superhydrophobic coating with mechanical stability, corrosion protection, and friction reduction abilities to inspire new applications of superhydrophobic surfaces.

Structure Optimization for Cellulose‐Based Separator through Fiber Size Regulation for High Performance Lithium Metal Batteries

Cellulose‐based separator exhibits excellent electrolyte affinity, thermal stability, and mechanical strength, which acts as a promising alternative to commercial polyolefin separators in lithium metal batteries (LMBs). Fiber size in cellulose‐based separators plays a crucial role in determining their physicochemical structure and mechanical strength, as well as the electrochemical performance of corresponding LMBs. Herein, the fiber size in cellulose‐based separators was first time regulated to optimize their mechanical stability and the related battery performance. The influences of fiber size in the separator on chemical structure, mechanical properties, surface morphology, electrochemical behavior were investigated in detail, in which the underlying mechanism between separator structure and the related performance was elucidated. As a result, the separator optimized by fiber size regulation exhibited excellent thermal stability under 180 °C, good tensile strengths of 6.0 MPa and Young's moduli of 315.9 MPa, superior room temperature ionic conductivity of 1.87 mS cm‐1, as well as significantly improved electrochemical performance of corresponding batteries. It can be concluded that structure optimization for cellulose‐based separator through fiber size regulation is an effective and indispensable approach towards high safety and high performance LMBs.

Electrode Binder Design on Silicon‐Based Anode for Next‐Generation Lithium‐Ion Batteries

AbstractAs an important part of the electrode material of lithium‐ion batteries, the binder significantly affects the forming strength of the solid electrolyte interface (SEI), and also determines the mechanical properties and cycling stability. In the silicon anode, binder have greater effect in the chemical and electrochemical stability because of the volume of the silicon anode changes by more than 300 %. Thus, the development of functional new binders with enhanced properties is one of the keys to mitigating the instability of silicon anodes. This concept first briefly introduces the advantages and disadvantages of conventional electrode binders, then the current research progress of silicon anode binders is briefly summarized based on the different types of interaction forces of binders. Finally, we conclude the properties indicators of silicon anode binders with superior performance in batteries, and comment our previous work in detail.

Enhancing the Mechanical Strength and Thermal Stability of Polylactic Acid (PLA) with the Addition of Epoxidized Waste Cooking Oil (EWCO)

Polylactic Acid (PLA) comes from renewable resources, has a reasonable biodegradability rate, and is used in biomedical, food packaging, textiles, and agricultural applications. PLA offers high mechanical strength and the ability to compost, similar to polyethylene terephthalate (PET) and nylon. However, the brittleness of PLA has always limited its usage. Therefore, bio-based plasticizers in the biopolymer matrices can increase flexibility (elasticity), durability, and workability. This study aims to determine the optimal blending ratio for the PLA blended with epoxidized waste cooking oil (EWCO) to enhance the mechanical and thermal properties of PLA/EWCO. The mechanical strength test consists of the hardness test (N/mm&lt;sup&gt;2&lt;/sup&gt;), flexural strength (MPa), and impact energy (kJ/m&lt;sup&gt;&lt;/sup&gt;) adopted to evaluate the plasticizing characteristics. The thermal stability analysis involves glass transition temperature (T&lt;sub&gt;g&lt;/sub&gt;) (°C), cold-crystallization temperature (T&lt;sub&gt;cc&lt;/sub&gt;) (°C) and melting temperature (T&lt;sub&gt;m&lt;/sub&gt;) (°C). The blending ratio is 97.5PLA/2.5EWCO, 95PLA/5EWCO, 92.5PLA/7.5EWCO and 90PLA/10EWCO. As a result, 97.5:2.5 of PLA/EWCO reduces intermolecular interactions by stimulating more free volume in biopolymer chains’ mobility and enhancing the flexibility and elasticity of the PLA blends. Ultimately, the brittleness of PLA decreased with increasing EWCO bio-based plasticizer.

Designed inorganics doped gel electrolyte with enhancing ion transfer and diffusion effects for flexible interdigitated supercapacitors

Electrolyte enhancement strategy becomes a promising route to improve flexible interdigitated miniaturized supercapacitors (IMSCs) performance due to the less mass loading of electrode materials on interdigitated electrodes. Herein, we develop a flexible polyvinyl alcohol/KOH (PVA/KOH) gel electrolyte with homogeneous BN-PDA (polydopamine modified boron nitride nanosheets) doping for enhancing energy storage of IMSCs, in which the conductivity is up to 112.1 mS cm−1 with excellent mechanical strength and heat stability. The ionicity of BN-PDA caused by electronegativity difference between B and N atoms significantly facilitates KOH transfer in PVA gel and diffusion in electrode diffuse layer by rapping-pairing effect. Furthermore, the different phase transition behavior of BN-PDA and PVA in water provides additional ions transmission pathways and effectively disperses external forces. With such excellent electrolytes, ultra-high energy density (14.7 μWh cm−2) at a high power density (420 μW cm−2) has been achieved for IMSCs. Moreover, the capacitance of IMSCs can always be maintained at a very high level during the long-term charge and discharge process. Our work suggests a feasible pathway to design inorganic fillers uniformly modified gel electrolyte with high conductivity and increased energy storage capacity of IMSCs as well as other flexible energy storage devices.

Preparation and mechanism research on hydrophobic coupling modification of HTV silicone rubber

Neat high-temperature vulcanized silicone rubber (HTV SR) showed bad hydrophobicity due to the existence of a large number of inorganic reinforcing fillers on its surface, which affected its security application in outdoor insulation systems. In this work, hydrophobic silane chains were grafted onto the surface of inorganic particles on the skin layer of HTV SR by a one-step coupling modification to improve its hydrophobicity. The effects of coupling agent types and coupling reaction conditions on the hydrophobicity of HTV SR were investigated. It was determined that the perfluorooctane trichlorosilicon with a large number of low surface energy fluorine atoms was the preferred coupling agent. The contact angle of HTV SR was increased by 15.70% when the optimal coupling reaction conditions were determined to be a reaction temperature of 60°C, a reaction time of 4 h, and an amount of coupling agent of 0.5%. The study found that both etching reaction and grafting reaction occurred during the whole coupling modification process, which led to the disappearance or decrease of a lot of holes on the HTV SR surface. After the fluorination coupling reaction, the surface of HTV SR became smooth and dense that led to the decrease of water absorption. The result of Fourier-transform infrared spectroscopy analysis showed the formation of C-F bond in HTV SR after fluorination modification, and the energetic dispersive spectroscopy analysis showed that the fluorine content on the surface of the fluorinated HTV SR increased significantly. Moreover, the stability analysis showed that the fluorinated HTV SR still had a good thermal stability and mechanical property stability.

Ultrasensitive Self-Powered Flexible Crystalline β-Ga2O3-Based Photodetector Obtained through Lattice Symmetry and Band Alignment Engineering.

Due to its portable and self-powered characteristics, the construction of Ga2O3-based semiconductor flexible devices that can improve the adaptability in various complex environments have drawn great attention in recent decades. However, conventional Ga2O3-based flexible heterojunctions are based on either amorphous or poor crystalline Ga2O3 materials, which severely limit the performance of the corresponding devices. Here, through lattice-symmetry and energy-band alignment engineering, we construct a high-quality crystalline flexible NiO/β-Ga2O3 p-n self-powered photodetector. Owing to its suitable energy-band alignment structure, the device shows a high photo-to-dark current ratio (1.71 × 105) and a large detection sensitivity (6.36 × 1014 Jones) under zero bias, which is superior than most Ga2O3 self-powered photodetectors even for those based on rigid substrates. Moreover, the fabricated photodetectors further show excellent mechanical stability and robustness in bending conditions, demonstrating their potential practical applications in flexible optoelectronic devices. These findings provide insights into the manipulation of crystal lattice and energy band engineering in flexible self-powered photodetectors and also offer guideline for designing other Ga2O3-based flexible electronic devices.

Ultraviolet active novel chalcogenides AScSe2 (A= K, Cs): The structural, optoelectronic, mechanical, vibrational, and thermodynamical properties for energy harvesting applications

It is essential nowadays to investigate some unique and appropriate materials for optoelectronic applications. We deliberate here for the first time, the structural, optoelectronic, mechanical, vibrational, and thermodynamical properties of hexagonal structured selenium-based ternary chalcogenides AScSe2 (A = K, Cs) by using Perdew-Burke-Ernzerhof Generalized-Gradient-Approximation (PBE-GGA). The lattice angles for these materials are found as α = β = 90° and γ = 120°. KScSe2 is optimized with lattice parameters a = b = 4.3 (Å), c = 7.81 (Å) whereas, CsScSe2 is relaxed at a = b = 4.43 (Å) and c = 8.51 (Å). The hybrid Heyd-Scuseria-Ernzerhof (HSE06) functional overestimates the lattice parameters to the extent that for KScSe2 these are found as a = b = 4.92 (Å), c = 7.10 (Å) and for CsScSe2 a = b = 5.15 (Å), c = 7.09 (Å). The energy band gap confirms the semiconducting nature of these materials. Born's criteria endorses the mechanical stability of these materials. Moreover, the temperature dependence of thermodynamic potentials and specific heat at constant volume is also determined using the harmonic approximation. The negative value of free energy ensures their thermodynamical stability. The vibrational modes are calculated by plotting the phonon dispersion and the vibrational density of states (VDOS) where infrared (IR) and Raman spectroscopy are used to characterize the vibrational modes. The optical parameters are examined at a smearing value of 0.5 eV that portray good absorptivity of the incident light from the Ultraviolet (UV) region. Thus, these materials may be potential ones to be utilized for energy harvesting applications via photovoltaic.