Durability Performance Research Articles

Ultralow-Power Programmable 3D Vertical Phase-Change Memory with Heater-All-Around Configuration.

Recent advancements in phase-change memory (PCM) technology have predominantly stemmed from material-level designs, which have led to fast and durable device performances. However, there remains a pressing need to address the enormous energy consumption through device-level electrothermal solutions. Thus, the concept of a 3D heater-all-around (HAA) PCM fabricated along the vertical nanoscale hole of dielectric/metal/dielectric stacks is proposed. The embedded thin metallic heater completely encircles the phase-change material, so it promotes highly localized Joule heating with minimal loss. Hence, a low RESET current density of 6-8 MAcm-2 and operation energy of 150-200 pJ are achieved even for a sizable hole diameter of 300nm. Beyond the conventional 2D scaling of the bottom electrode contact, it accordingly enhances ≈80% of operational energy efficiency compared to planar PCM with an identical contact area. In addition, reliable memory operations of ≈105 cycles and the 3-bits-per-cell multilevel storage despite ultrathin (<10nm) sidewall deposition of Ge2Sb2Te5 are optimized. The proposed 3D-scaled HAA-PCM architecture holds promise as a universally applicable backbone for emerging phase-change chalcogenides toward high-density, ultralow-power computing units.

Performance Verification and Evaluation of Semi-Active Actuator System Using Quarter Car Lab Simulation with RLDA Data

This study outlines a methodology for determining the durability specifications of electronically controlled dampers by examining performance degradation observed on actual driving roads. It identifies areas of performance decline and the primary causes affecting major actuator dampers. Traditionally, the durability performance of automobile parts has been assessed by calculating damage based on load profiles. However, analyzing actual road conditions is essential because the control commands of electronically controlled suspension systems change in real time according to load conditions. Simulations based on Road Load Data Acquisition (RLDA) use statistically independent representative road surfaces to assess damper deterioration performance. Following this analysis, a rig test of the damper is performed to establish the durability specifications for damper actuator products. The primary form of performance degradation observed was a change in the tensile damping force, which was more substantial than the degradation observed on the compression side. Oil leakage and cavitation were identified as significant influencing factors from a Failure Mode and Effects Analysis (FMEA) perspective. The study concludes that additional design research is necessary, focusing on damper oil and leakage, while also considering the control algorithm’s effects in designing electronically controlled dampers.

Mechanical, Durability, and Microstructure Characterization of Pervious Concrete Incorporating Polypropylene Fibers and Fly Ash/Silica Fume

Pervious concrete, because of its high porosity, is a suitable material for reducing the effects of water precipitations and is primarily utilized in road pavements. In this study, the effects of binder-to-aggregate (B/A) ratios, as well as mineral admixtures with and without polypropylene fibers (PPFs) (0.2% by volume), including fly ash (FA) or silica fume (SF) (10% by substitution of cement), on the mechanical properties and durability of pervious concrete were experimentally observed. The experimental campaign included the following tests: permeability, porosity, compressive strength, splitting tensile strength, and flexural strength tests. The durability performance was evaluated by observing freeze–thaw cycles and abrasion resistance after 28 d curing. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA-DTA), and scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS) were employed to investigate the phase composition and microstructure. The results revealed that, for an assigned B/A ratio identified as optimal, the incorporation of mineral admixtures and fibers mutually compensated for their respective negative effects, resulting in the effective enhancement of both mechanical/microstructural characteristics and durability properties. In general, pervious concrete developed with fly ash or silica fume achieved higher compressive strength (&gt;35 MPA) and permeability of 4 mm/s, whereas the binary combination of fly ash or silica fume with 0.2% PPFs yielded a flexural strength greater than 6 MPA and a permeability of 6 mm/s. Silica fume-based pervious concrete exhibited excellent performance in terms of freeze–thaw (F-T) cycling and abrasion resistance, followed by fiber-reinforced pervious concrete, except fly ash-based pervious concrete. Microstructural analysis showed that the inclusion of fly ash or silica fume reduced the harmful capillary pores and refined the pore enlargement caused by PPFs in the cement interface matrix through micro-filling and a pozzolanic reaction, leading to improved mechanical and durability characteristics of pervious concrete.

Tensile strength and durability performances-based evaluation of 3D-printed and mold-cast fibrous geopolymer composites produced at various alkaline activator combinations

This study aimed to investigate the effects of the sodium silicate-to-sodium hydroxide ratio, SH molarity, and carbon fiber volume fraction on the tensile strength and durability properties of mold-cast and 3D-printed geopolymer composites, including flexural and splitting tensile strengths, ultrasonic pulse velocity, water absorption, sorptivity index, and chloride penetration properties. For that purpose, the ground-granulated blast furnace slag and fly ash were employed as alumino-silicate-rich raw material. In order to activate the alumino-silicate-rich raw material, two sodium silicate/sodium hydroxide ratios of 1 and 2 and three sodium hydroxide molarities of 8M, 10M, and 12M were designated. Furthermore, carbon fiber was incorporated into the geopolymer composites at three volume fractions: 0%, 0.3%, and 0.6%. In total, 18 nonfibrous and fibrous geopolymer composites were manufactured in two different ways: mold-cast and 3D-printed. The findings demonstrated that the strength and durability characteristics of 3D-printed specimens were inferior to those of mold-cast specimens, attributed to the presence of weak interfacial bonds between layers. It has been observed that the incorporation of carbon fiber has the effect of improving tensile strength performance. Nevertheless, the addition of carbon fiber led to a slight decrease in UPV values, and an increase in water absorption and sorptivity index values. Also, it adversely influenced the chloride penetration of geopolymer composites. The findings of the study also indicated that increasing the sodium hydroxide molarity had a positive impact on the strength and durability properties of the composites. Nevertheless, it was observed that increasing the sodium silicate-to-sodium hydroxide ratio led to a decrease in both tensile strength and durability performances. Additionally, the microstructure of the geopolymer composites was analyzed using scanning electron microscope (SEM) images.

Long-term investigation of uniaxial compressive and self-sensing performances of ultra-high performance seawater sea-sand concrete incorporating superfine stainless wires: Insights into underlying mechanisms and theoretical models

Developing intrinsic self-sensing concrete is expected to provide a digital intelligence solution to address the infrastructure’s challenges in terms of safety, lifespan, resilience, and carbon emission reduction. Using seawater and sea-sand as well as corrosion-resistant conductive fillers to fabricate self-sensing ultra-high seawater sea-sand performance concrete (UHPSSC) with outstanding mechanical and durability performances is the prerequisite for realizing localized resource utilization and in-situ monitoring of marine infrastructure. However, the potential effect of ions from seawater and sea-sand on the long-term stability of mechanical and electrical performances cannot be ignored. This paper presents a long-term investigation of uniaxial compressive, electrical, and self-sensing performances of superfine stainless wires (SWs) reinforced UHPSSC under natural curing. The results show that incorporating 1.5% SWs improves the compressive strength, elastic modulus, peak strain, and toughness of UHPSSC by 25.0%, 11.7%, 33.8%, and 119.2%, respectively. The established statistical damage constitutive models based on Weibull strength theory highlight the roles of SWs in delaying crack initiation. The dense microstructure of SWs-reinforced UHPSSC inhibits the growth of expansive hydration products formed by corrosive ions, thus guaranteeing its long-term strength development. Additionally, due to incorporating 1.5% SWs, the electrical resistivity of UHPSSC is reduced by seven orders of magnitude, with a strain sensitivity of 119.1 under monotonic compressive loading and a monitoring stress range of 0-148.4 MPa, indicating that SWs-reinforced UHPSSC can sense its stress and strain while providing early warning of crack initiation and propagation. Benefiting from the rust-free property, micron diameter, and high aspect ratio of SWs, the primary conductive path of composites comprises the overlapping networks formed by low-content SWs, which are not influenced by the ion conduction of conductive ions. Hence, SWs-reinforced UHPSSC exhibits stable electrical resistivity and sensitivity during long-term curing, suggesting its considerable potential for long-term in-situ monitoring of marine infrastructure.

Microstomia- A Review Of Published Case Reports On The Proposed Management Of Microstomia

Introdcution: microstomia, or the reduction of oral opening, can indeed present challenges for patients across various contexts, from eating and speech to prosthetic treatment. It's essential for clinicians to understand the underlying causes and tailor their approach accordingly. By synthesizing existing evidence, this review aims to provide insights into the effectiveness and feasibility of different prosthetic interventions, thereby guiding clinicians in their decision-making process for optimal patient care. Materials and methods: published case reports and case series reporting on prosthetic rehabilitation of microstomia patients were included in the present review. Only cases with a reduction in the size of the oral aperture were included, and cases with reduced mouth opening with a normal oral aperture (e.g., oral submucous fibrosis, temporal-mandibular joint ankylosis, etc.) Were excluded. Case reports: (case report1) a 93-year-old woman without teeth was referred from the local hospital to the department of oral rehabilitation at the faculty of dentistry, university of otago, dunedin, new zealand. The woman's surgeries on her lower lip resulted in a significant reduction in the vertical opening distance between her upper and lower lips, now at 30 mm. This condition, known as microstomia. (case report 2) a 62-year-old male patient, completely without teeth, presented to the prosthodontic department due to functional difficulties. Discussion: a planned and step-by-step approach is crucial when dealing with cases of microstomia. The outcome greatly depends on the complexity of the case and the utilization of recommended materials and equipment hence, diagnosis and treatment planning play pivotal roles in the management process. Conclusion: although the utilization of flexible denture materials holds promise in enhancing patient comfort and treatment outcomes, further research is warranted to evaluate their long-term success rates. Longitudinal studies can furnish valuable insights into the durability, stability, and overall performance of these materials over time, assisting clinicians in decision-making and optimizing patient care.

Effects of Superabsorbent Polymer and Natural Zeolite on Shrinkage, Mechanical Properties, and Porosity in Ultra-High Performance Concretes

The low water-to-binder ratio of ultra-high performance concrete (UHPC) often causes shrinkage and cracking due to early-age self-desiccation. This leads to significant initial dimensional instability, which may compromise structural integrity. As a promising solution, internal curing agents such as superabsorbent polymers (SAP) and natural zeolite have the potential to mitigate shrinkage and achieve self-stressing properties. This research aims to provide a comprehensive comparison between SAP and zeolite's effects within a consistent UHPC formulation. Six UHPC mixtures (including the reference mixture) were designed: three with SAP dosages of 0.2%, 0.4%, and 0.6% by cement mass, and two with zeolite replacing silica fume at 25% and 50% by mass. Various testing methods, including autogenous and drying shrinkage assessment, heat of hydration and thermogravimetric analysis, compressive strength evaluation, mercury intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), were employed to assess the mixtures at different stages of curing. The result reveals that the incorporation of SAP and zeolite in the mixtures significantly reduces UHPC's early-age autogenous shrinkage. Moreover, SAP and zeolite additions impact mechanical properties, demonstrating that a balance between shrinkage control and compressive strength can be reached, through an optimization of the additions to achieve the desired performance. Microstructural analysis through MIP and NMR reveals increased overall porosity of the UHPC with SAP and zeolite, suggesting that low-field NMR can be a valuable tool for complementing conventional test methods. The outcome of this study provided valuable insights into optimizing the balance between durability and mechanical performance, paving the way for more sustainable and cost-effective applications of UHPC in modern construction practices.

Fatigue life prediction of BGA solder joint of several alloy compositions under an isothermal harmonic vibration

To ensure durable performance and optimal function of electronic components, it is crucial to guarantee their reliability, robustness and goodness of fit. The solder joints used in the BGA (Ball Grid Array) component play an intrinsic role in the reliability of the system. The vibration present in BGA triggers fatigue in solder joints, which raises a major reliability problem in various sectors such as aerospace, automotive and military industries. This study handles the response to a harmonic vibration at three specific temperatures (−40°C, 25°C, and 125°C) for four types of solder alloys in BGA Soldering. Within this framework, predicting the fatigue life of BGA solder joints with various alloy compositions under the influence of an isothermal harmonic vibration emerges as a crucial challenge in the design as well as reliability of modern electronic devices. The investigated solder compositions are SAC105, SAC305, SAC405, and InnoLot. To simulate and analyze the behavior of solder joints, we used the Ansys APDL finite element analysis (FEA). At both 125°C and −40°C, the Von Mises values proved to exceed those observed at 25°C. Likewise, an S-N curve for InnoLot and the different SACs, under a harmonic vibration at 25°C, was fitted using the Basquin power law relationship. As far as the current research work is concerned, an initial comparison was enacted between InnoLot and SAC alloys under an isothermal harmonic vibration, aiming to ascertain the most reliable alloy. The fatigue life under a harmonic vibration loading at 25°C was estimated. The results revealed that under a harmonic vibration at 25°C, the InnoLot solder displayed the longest lifespan, while the SAC105 solder exhibited the shortest fatigue life.

Mechanical and Durability Properties of Rubberized Sulfur Concrete Using Waste Tire Crumb Rubber

The use of rubber crumbs provides a viable solution for alleviating the disposal problem of waste tires. In this study, rubberized sulfur concrete (RSC) was researched to investigate the optimal mixture proportion and to improve the mixing process in terms of compressive strength and durability performance. For the mixture of the RSC, sand, rubber particles, and micro-filler were adopted as aggregates and sulfur was used for the binding material. Moreover, two mixing processes were applied: the dry mixing process and the wet mixing process. Based on the test results, the increment of rubber particles in the mixture led to a decrease in the compressive strength for both the dry and wet mixing processes. To minimize the voids between the sand and rubber particles, the micro-filler was used at 5% of the total volume. The amount of sulfur varied slightly depending on the mixing process: 30% sulfur for the dry mixing process and 34% sulfur for the wet mixing process, respectively. Consequently, compared to the dry mixing process, the wet mixing process increased the bonding force between sulfur and rubber powder due to the simultaneous heating and combining. In toughness, the wet mixing process demonstrates a 40% higher energy absorption capability compared to the dry mixing process. For the durability performance of the RSC, the mixture with 20% rubber particles produced using the wet mixing process exhibited better corrosion and freeze–thaw resistance.

Evaluating the combined effect of sugarcane bagasse ash, metakaolin, and polypropylene fibers in sustainable construction

The major challenge for the construction industry is to design and produce sustainable construction materials that are efficient in their performance and can be affordable for construction projects. The objective of this study is to determine the viability of incorporating waste products such as sugarcane bagasse ash (SCBA) to produce concrete with polypropylene (PP) fibers. SCBA is an industry waste that has certain pozzolanic properties, however, it shows limited mechanical properties when used as a cement replacement. To improve the mechanical and durability performance, metakaolin (15%) and PP fiber (0.5%, 1%, and 1.5%) were incorporated in the SCBA blend as a ternary additive. Some of the important characteristics explored include compressive strength, tensile strength, density, water absorption, acid resistance, and sorptivity. The study reveals that the incorporation of 15% metakaolin in the composite enhanced the compressive strength by 7%, 8.2%, and 9.1% for PP fiber additions of 0.5%, 1%, 1.5%, while the acid resistance enhanced by 4%, 6% and 8% relative to the control mix for the same value of pp fiber. Furthermore, cost evaluation confirms that the overall costs of concrete with 15% metakaolin and 5% SCBA were 12.2% less than the control concrete, thus making this option economically feasible. This research proves that the inclusion of SCBA, metakaolin, and PP fibers into the concrete mixture brings a sustainable approach that enhances mechanical properties and durability while assisting sugar manufacturing plants in the proper disposal of wastes.

A Rechargeable Urea-Assisted Zn-Air Battery With High Energy Efficiency and Fast-Charging Enabled by Engineering High-Energy Interfacial Structures.

Electrochemical urea oxidation reaction (UOR) offers a promising alternative to the oxygen evolution reaction (OER) in clean energy conversion and storage systems. Nickel-based catalysts are regarded as highly promising electrocatalysts for the UOR. However, their effectiveness is significantly hindered by the unavoidable self-oxidation reaction of nickel species during UOR. To address this challenge, we proposed an interface chemistry modulation strategy to boost UOR kinetics by creating a high-energy interfacial heterostructure. This heterostructure incorporates Ag at the CoOOH@NiOOH heterojunction interface, where strong interactions significantly promote the electron exchanges at the heterojunction interface between -OH and -O groups. Consequently, the improved electron delocalization leads to the formation of stronger bonds between Co sites and urea CO(NH2)2, promoting a preference for urea to occupy Co active sites over OH*. The resulting catalyst, Ag-CoOOH@NiOOH, demonstrates ultrahigh UOR activity with a low potential of 1.33 V at 100 mA cm-2. The fabricated catalyst exhibits a mass activity over 11.9 times greater than the initial cobalt oxyhydroxide. The rechargeable urea-assisted zinc-air batteries (ZABs) achieve a record-breaking energy efficiency of 74.56 % at 1 mA cm-2, remarkable durability (1000 hours at a current density of 50 mA cm-2), and quick charge performances.

Highly Conducting and Ultra-Stretchable Wearable Ionic Liquid-Free Transducer for Wireless Monitoring of Physical Motions.

Wearable strain transducers are poised to transform the field of healthcare owing to the promise of personalized devices capable of real-time collection of human physiological health indicators. For instance, monitoring patients' progress following injury and/or surgery during physiotherapy is crucial but rarely performed outside clinics. Herein, multifunctional liquid-free ionic elastomers are designed through the volume effect and the formation of dynamic hydrogen bond networks between polyvinyl alcohol (PVA) and weak acids (phosphoric acid, phytic acid, formic acid, citric acid). An ultra-stretchable (4600% strain), highly conducting (10 mScm-1), self-repairable (77% of initial strain), and adhesive ionic elastomer is obtained at high loadings of phytic acid (4:1 weight to PVA). Moreover, the elastomer displayed durable performances, with intact mechanical properties after a year of storage. The elastomer is used as a transducer to monitor human motions in a device comprising an ESP32-based development board. The device detected walking and/or running biomechanics and communicated motion-sensing data (i.e., amplitude, frequency) wirelessly. The reported technology can also be applied to other body parts to monitor recovery after injury and/or surgery and inform practitioners of motion biomechanics remotely and in real time to increase convalescence effectiveness, reduce clinic appointments, and prevent injuries.

Study on the Effect of Jute CNFs Addition on the Water Absorption and Mechanical Properties of Geopolymer Concrete

This study investigates the influence of thermoplastic polyurethane (TPU) reinforced with jute cellulose nanofibers (CNFs) on the water absorption and mechanical properties of geopolymer concrete. The integration of TPU/jute CNF nanocomposites into geopolymer concrete is explored as a strategy to enhance both its durability and mechanical performance. Geopolymer concrete, a sustainable alternative to traditional Portland cement concrete, is known for its low carbon footprint, but it suffers from high brittleness and water absorption. The water absorption behavior of the modified concrete was assessed, revealing a significant reduction in water uptake due to the hydrophobic nature of TPU and the reinforcing effect of jute CNFs. Additionally, the mechanical properties, including compressive and flexural strengths, were evaluated to understand the impact of the nanocomposites on the structural integrity of the concrete. The addition of TPU/jute CNFs notably enhanced the splitting tensile strength (63.5%), compressive strength (59%), and water absorption (0.59%) of the composite, indicating a promising route for developing high-performance construction materials. The integration of 6 wt% of TPU/jute CNF nanocomposites was found to be optimal, resulting in a uniform matrix, reduced micro-cracks, and improved compressive strength due to enhanced adhesion between the nanocomposites and the geopolymer matrix. Furthermore, a curing temperature of 100 °C was identified as ideal, minimizing unreacted fly ash and enhancing adhesion strength, while higher temperatures (140 °C) led to material deterioration due to rapid water loss. The findings demonstrate that the addition of TPU/jute CNF nanocomposites not only improves resistance to water penetration but also enhances overall mechanical performance. This supports the development of more sustainable and resilient construction materials, contributing to global efforts to reduce the environmental impact of the construction industry. Future research should focus on the long-term durability of these composites under various environmental conditions to validate their effectiveness in real-world applications.

Comparative Analysis of Mechanical Characteristics: Ultrasonically Compacted vs. Conventionally Additive Manufactured Polymeric Samples

This scientific paper presents a comparative analysis of the mechanical characteristics of PLA samples fabricated through conventional AM methods and AM then ultrasonically compacted. The study aims to assess the potential advantages and limitations of ultrasonic compaction of PLA AM samples, as a reinforcing manufacturing technique. The methodology involves the fabrication of PLA samples using AM processes, then ultrasonically compact part of them to make a comparative study on their mechanical characteristics, including tensile strength. Additionally, the surface morphology and internal microstructure of the samples are analysed using microscopy techniques. The results of the study provide insights into the mechanical performance and structural integrity of the ultrasonically compacted samples compared to the conventionally PLA AM samples. The findings highlight any potential improvements or limitations in terms of mechanical properties, such as strength, durability, and overall performance.

A compliant mechanism actuated bistable hybrid mode triboelectric nanogenerator

Abstract Triboelectric nanogenerators (TENGs) working in sliding mode offer higher power generation capability compared with those working in contact-separation mode (CS-TENGs). However, unlike CS-TENGs, sliding action can limit TENG lifespan due to wear and tear. A TENG combining both modes with intermittent sliding actions can overcome this limitation. In this study, we propose a bistable hybrid mode TENG (BHM-TENG) that can leverage the functionalities of the traditional sliding TENG and CS-TENG and achieve both durability and satisfactory performance, enabled by a compliant mechanism design. A self-rotating base introduces sufficient sliding during intermittent contact, leading to significant improvement in charge transfer (44%) and voltage output (58%) compared with the conventional TENGs while minimising wear and tear. The prototyped device, excited using compliant beams, can be effectively actuated even at extremely low input frequencies (&lt;0.1 Hz), as explained by a mathematical model. The real-world energy harvesting applications enabled by BHM-TENG is proposed based on the output of BHM-TENG.&amp;#xD;

Response tests on the effects of particle size of waste glass sand and glass powder on the mechanical and durability performance of concrete

To investigate the effect of waste glass material particle sizes on the mechanical and durability properties of concrete, a two-phase experimental approach was conducted. First, comprehensive tests were performed to examine the effects of glass sand and glass powder of different particle sizes on concrete performance. Subsequently, based on the experimental results, an orthogonal test was designed to optimize the replacement amounts of composite particle sizes. The results indicated that an appropriate amount of glass sand can enhance the mechanical properties and durability of concrete, while excessive amounts or larger particle sizes may have adverse effects. The pozzolanic effect of glass powder also contributes to performance improvement, but the replacement rate should be limited to 20%. Under composite particle size conditions, the compressive, tensile, and shear strengths of concrete increased by 35.56%, 21.74%, and 13.79%, respectively, while durability significantly improved, with water absorption reduced by 20.73% and chloride ion permeability decreased by 63.10%. At a total replacement rate of 20%, the optimal proportions were determined to be 2.86% for 0.6 mm glass sand, 1.43% for 1.18 mm glass sand, 8.57% for 50–60 μm glass powder, and 7.14% for 60–70 μm glass powder. The incorporation of composite particle sizes improved the microstructure of concrete, thereby enhancing its mechanical and durability properties.

Mitigating the Kinetic Hysteresis of Co-Free Ni-Rich Cathodes via Gradient Penetration of Nonmagnetic Silicon.

Co-free Ni-rich layered oxides are considered a promising cathode material for next-generation Li-ion batteries due to their cost-effectiveness and high capacity. However, they still suffer from the practical challenges of low discharge capacity and poor rate capability due to the hysteresis of Li-ion diffusion kinetics. Herein, based on the regulation of the lattice magnetic frustration, the Li/Ni intermixing defects as the primary origin of kinetic hysteresis are radically addressed via the doping of the nonmagnetic Si element. Meanwhile, by adopting gradient penetration doping, a robust Si-O surface structure with reversible lattice oxygen evolution and low lattice strain is constructed on Co-free Ni-rich cathodes to suppress the formation of surface dense barrier layer. With the remarkably enhanced Li-ion diffusion kinetics in atomic and electrode particle scales, the as-obtained cathodes (LiNixMn1-xSi0.01O2, 0.6≤x≤0.9) achieve superior performance in discharge capacity, rate capability, and durability. This work highlights the coupling effect of magnetic structure and interfacial chemicals on Li-ion transport properties, and the concept will inspire more researchers to conduct an intensive study.

Mitigating the Kinetic Hysteresis of Co‐Free Ni‐Rich Cathodes via Gradient Penetration of Nonmagnetic Silicon

AbstractCo‐free Ni‐rich layered oxides are considered a promising cathode material for next‐generation Li‐ion batteries due to their cost‐effectiveness and high capacity. However, they still suffer from the practical challenges of low discharge capacity and poor rate capability due to the hysteresis of Li‐ion diffusion kinetics. Herein, based on the regulation of the lattice magnetic frustration, the Li/Ni intermixing defects as the primary origin of kinetic hysteresis are radically addressed via the doping of the nonmagnetic Si element. Meanwhile, by adopting gradient penetration doping, a robust Si−O surface structure with reversible lattice oxygen evolution and low lattice strain is constructed on Co‐free Ni‐rich cathodes to suppress the formation of surface dense barrier layer. With the remarkably enhanced Li‐ion diffusion kinetics in atomic and electrode particle scales, the as‐obtained cathodes (LiNixMn1−xSi0.01O2, 0.6≤x≤0.9) achieve superior performance in discharge capacity, rate capability, and durability. This work highlights the coupling effect of magnetic structure and interfacial chemicals on Li‐ion transport properties, and the concept will inspire more researchers to conduct an intensive study.

A comparative experimental study on abrasive flow machining vs flow peening GOV processes on Inconel 718

Inconel 718, a nickel-based super alloy, has a broad applications area from aerospace, medical and defence to traditional industries because of its high durability, corrosion resistance and elevated temperature performance. Unconventional surface treatment methods of abrasive flow machining (AFM) and shot peening (SP) are applied to improve the mechanical performance of Inconel 718. In this work, a new surface treatment process known as flow peening (GOV) already developed by combining the advantages of abrasive flow machining (AFM) and shot peening methods such as surface finishing and residual compressive stress generation respectively was applied experimentally for Inconel 718. The effects of process parameters for GOV and AFM processes on the surface quality of the specimens were experimentally investigated. White layer decrease, surface roughness decrease and material removal amount were discussed for both processes. The best surface quality with 0.56 μm Ra surface roughness value and material removal amount of 7.2 mg were obtained by GOV process while similar level of surface roughness value of 0.52 μm was obtained by removing 6648.03 mg material for AFM. When the AFM process was continued, the best values of 0.24 μm Ra was obtained removing excess material of 17,385.60 mg compared to the GOV process. Also, all these results were supported by SEM images.

Mechanical and durability performance of eco-friendly geopolymer-stabilized soil

This work compared the mechanical performance and the durability of clayey soil stabilized using mechanochemically activated geopolymer (MAG) with conventionally activated geopolymer (CAG). The effect of ground-granulated blast-furnace slag (GGBS) content on the long-term durability of geopolymer-stabilized soil has also been studied. The samples of geopolymer stabilized soils were immersed in 1% magnesium sulphate (MgSO4) solution for 60 and 120 days. The appearance, ultrasonic pulse velocity, unconfined compressive strength (UCS), and FTIR spectroscopy of those samples were considered to evaluate their sulphate erosion resistance. Before the exposure to the MgSO4 solution, the UCS of MAG samples was higher (12%–45%) than that of CAG-stabilized soil. Furthermore, the strength of the geopolymer-stabilized soil improved by 114%, 247%, and 361%, at 50%, 75%, and 100% GGBS content, respectively. After exposure to the MgSO4 solution, the results showed that the mechanochemically activated geopolymer-stabilized soil has better resistance to sulphate erosion than the conventionally activated geopolymer-stabilized soil. The residual UCS for MAG and CAG samples were 93% and 89% when exposed to 1% magnesium sulphate solution for 60 days, whereas they declined to 70% and 58%, respectively, after 120 days of immersion.