Material Characteristics Research Articles

Modern innovations in the provision and efficient application of 2D inorganic nanoscale materials

Abstract Two-dimensional nanoscale materials (2D NMs) have exceptional physical characteristics, distinctive structures, and customizable surface chemistry. They consist of infinite transverse dimensions of near-atomic thickness or atoms. They promise advancements in catalysis, renewable energy, and sensing. An extensive summary of the most recent research results on the creation and use of 2D NMs is provided in this work. It is possible to modify the characteristics of these multi-layered materials by means of chemical and physical manipulations. Due to their layer-dependent electrical properties, certain 2D layered inorganic nanomaterials such as MoS2, WS2, and SnS2 have recently been created and used in a variety of applications, including new sensors. In addition, the article delves into the difficulties confronted by sectors reliant on nanotechnology as well as the potential future uses of nanostructures coupled with electrochemical systems. The article begins by outlining the typical “top-down” and “bottom-up” approaches for synthesizing 2D NMs. These approaches include hydrothermal procedures, ion intercalation, mechanical exfoliation, liquid-phase exfoliation assisted by ultrasonic waves, and chemical vapor deposition. 2D NMs are the focus of this work because of their potential applications in gas sensing, photocatalysis, electrocatalysis, photo detection, and electromagnetic wave absorption. In addition, the study predicts patterns of future development and possible issues with 2D NMs based on existing studies. Increased demand for cost-effective, environmentally friendly, and highly connected products is propelling the ongoing research and development of these high-performance materials. This research is significant since it summarizes, in one place, the most recent advances in 2D NM preparation methods and applications.

CCZM‐based fatigue analysis and reliability assessment for wind turbine blade adhesive joints considering parameter uncertainties

AbstractWind turbine blades are complex structures composed of multiple bonded components. The fatigue performance of these adhesive joints is crucial for ensuring operational safety over the blade's lifespan. Traditional structural fatigue analysis methods are inadequate for evaluating the fatigue properties of these joints due to the unique characteristics of adhesive materials. Variations in material and dimensional parameters, as well as fluctuating operational loads, further complicate the fatigue analysis of adhesive joints in wind turbine blades. To tackle this issue, this study introduces a fatigue analysis and reliability assessment method for the adhesive joints of wind turbine blades, employing the Cyclic Cohesive Zone Model (CCZM) and accounting for parameter uncertainties. Specifically, a novel methodology for fatigue analysis based on the CCZM is presented. The methodology is programmatically implemented to obtain a fatigue life dataset through multiple simulations, considering uncertainties in material parameters, adhesive dimensions, and loads. Subsequently, a fatigue reliability model is formulated to evaluate the fatigue reliability of adhesive joints in wind turbine blades under different parameter conditions, and the sensitivity of fatigue reliability to each parameter is investigated. The findings offer valuable insights for improving the safety and reliability of adhesive structures in wind turbine blades.

Establishing a new efficiency descriptor for methanol oxidation reaction and its validation with commercially available Pt‐based catalysts

AbstractDirect methanol fuel cells (DMFCs) have received a lot of attention in recent years as promising technology for generating clean and efficient energy. In DMFC, the anode catalyst is a vital component because it is involved in the oxidation of methanol, which produces electrons that can be used as an energy source. Cyclic voltammetry (CV) is commonly used to test the characteristics of the electrode materials before they are employed in the actual fuel cell. Interestingly in the case of DMFCs CV also is a useful technique to obtain vital information about the performance and expected efficiency of the electrodes. In general, the CV of methanol electrooxidation for Pt‐based catalysts has two peaks, If in the forward scan (anodic scan) and Ib in the backward scan (cathodic scan). The ratio of these two peaks (If/Ib) is the most commonly used criterion for investigating CO poisoning in catalysts. However, there is a great deal of ambiguity surrounding this criterion, owing to the genesis of Ib. Addressing this we present here a new criterion to evaluate the efficiency of the catalyst using the same CV technique. We validate this newly proposed criterion with commercial Pt/C (comm. Pt/C) and other commercially available alloy catalysts.

Statement of Retraction: Analysis of material and craft aesthetics characteristics of arts and crafts works based on computer vision

Statement of Retraction: Analysis of material and craft aesthetics characteristics of arts and crafts works based on computer vision

A study on the effect of laser decontamination by beam overlap rate of crud formed on aluminum alloy

The corrosion products formed on the internal surfaces of the primary system are the major factor that generates radioactive contaminants such as oxide films and cruds during decommissioning, causing radiation exposure to workers. Thus, decontamination of nuclear facility surfaces is crucial to ensure the safe completion of decommissioning work. This study applied laser decontamination, which enables precise work while minimizing the deformation of the material surface through the control of process parameters, and investigated the characteristics of the decontaminated area. Specimens coated with Ni-ferrite on an aluminum alloy (A6061) substrate were fabricated and used in this experiment. Laser decontamination was performed using a low-power Q’switching fiber laser while varying the laser beam overlap rate and number of scans. The results of laser decontamination differed by the process parameters and material characteristics. It is determined that high decontamination efficiency can be achieved if appropriate conditions are applied.

On the importance of varying device thickness and temperature on the outcome of space-charge-limited current measurements

Space-charge-limited current (SCLC) measurements are commonly employed to characterize charge-transport properties of semiconductors used in next-generation thin-film optoelectronics, such as organic π-conjugated small molecules and polymers, and metal-halide perovskites. Despite the wide-spread adoption of the method, there is no community-wide consensus around how SCLC measurements should be performed, nor how the data should be analyzed and reported. While it is common to report device characteristics by employing a simplistic analytical model for fitting a single J-V curve obtained from a solitary device at room temperature—sometimes in a very select voltage range—expectedly, such an approach will often not give an accurate picture of the underlying physics. On that account, we here aim to highlight the importance of reporting values extracted from not just a solitary single-carrier device measured at room temperature, but from devices with different thicknesses measured at varying device temperature. We also highlight how the choice of device thickness is especially critical in determining what device and material characteristics can be extracted from SCLC measurements, and how this choice can greatly affect the conclusions drawn about the probed semiconducting material. While other factors could affect the outcome of an SCLC measurement and the subsequent analysis, we hope that the topics covered in this article will result in overall improved charge-transport characterization of thin-film semiconductors and initiate a broader discussion into SCLC metrology at large.

Photoexcited Carrier Dynamics in Iodine-Doped CH3NH3PbBr3 Single Crystals.

Iodine-doped bromide perovskite single crystals (IBPSCs) have important applications in optoelectronic fields, such as in solar cells. Currently, much research has aimed to study the phase separation phenomenon and device performance improvements in IBPSCs. However, important intrinsic photoexcited carrier dynamics are often overlooked in IBPSCs. Here, we explored the photoexcited carrier dynamics in typical iodine-doped MAPbBr3 single crystals using the excitation intensity-dependent steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL) technique. We found that the trap state density changes with an increase in the amount of doped iodine. Further, we noticed that there is an influence of carrier diffusion on the photoexcited carrier dynamics, and then, we evaluated the carrier diffusion coefficients and recombination constants via numerical simulations of the PL kinetics. Consequently, we found that the electron shallow trap-related carrier behaviors substantially impacted the PL kinetics. Our results greatly facilitate a deeper understanding of the fundamental characteristics of mixed halide perovskite material.

Utilization of nanotalc modified adhesives in plywood panels

As an alternative for the partial replacement of synthetic adhesives are the modifications that occur still during their synthesis, to improve and adhere new properties. Among the possible materials used in nanoscale, talc is a mineral material of natural origin and a promising raw material due to its low cost, lightness, natural hydrophobicity. Due to the scarcity of studies with the insertion of nanotalc in adhesives, this study aimed to produce plywood panels bonded with phenol-formaldehyde adhesive nanomodified with talc to evaluate its physical-mechanical resistance when compared to conventional synthetic adhesives. To carry out this study, three Pinus oocarpa trees with 28 years of age were used. Different concentrations of talc were used in the formulation with the phenol-formaldehyde adhesive, being the treatments 0; 0,05; 1; 1,5 and 2 % of talc (mass/mass) in relation to the adhesive, with three panels per treatment, totaling 15 panels. The pressing time was 8 minutes with temperature of 160 ºC and pressure of 1 MPa. The physical-chemical characteristics of the lignocellulosic material and of the plywood panels were determined. The quality of the adhesive produced was demonstrated by its resistance to water absorption with the insertion of up to 2 % talc to the adhesive, reducing it considerably. From 1 % talc inserted, the plywood panels had their mechanical characteristics superior to those glued with pure phenol-formaldehyde adhesive. However, as the study is innovative in nature, further research should focus on the application and quality evaluation of other talc nanomodified adhesives on different types of wood panels.

Engineering Porous Carbon with Precise Sizes to Promote Surface‐Dominated Storage in Sodium‐Ion Batteries

AbstractAs the sole commercially viable anode material for sodium‐ion batteries, hard carbon currently faces challenges such as slow diffusion kinetics in the low voltage range and low safety due to sodium deposition. In order to deepen the understanding of the pseudocapacitive processes of hard carbon in the high voltage range and enhance sodium storage capacity, this study systematically investigates the electrochemical performance and ion storage of ZIF‐8‐derived porous carbons (ZPCs) of different sizes. We propose a mathematical model based on a spherical particle core‐shell structure, which profoundly reveals the relationship between size and specific surface area, as well as the linear relationship between specific surface area and specific capacity. Moreover, simply by reducing the size of the porous carbon, the specific capacity increased by 86.5 mAh g−1. Dynamic studies reveal that in nano‐porous carbon materials, sodium‐ion storage primarily relies on defect adsorption. Size reduction enhances physical adsorption and surface capacitance response, with ZPC‐80 exhibiting lower resistance and higher diffusion coefficient, indicating that size reduction improves electronic conductivity and charge transfer efficiency, achieving excellent reversible capacity and cycling stability. This work yields a profound insight into the dynamic characteristics of hard carbon anode materials, presenting a new perspective for the design of efficient sodium‐ion batteries.

Effect of Physicochemical Surface Properties of Silicon-Substitute hydroxyapatite on Angiogenesis.

Synthetic hydroxyapatite (HA) is a widely studied bioceramic for bone tissue engineering (BTE) due to its similarity to the mineral component of bone. As bone mineral contains various ionic substitutions that play a crucial role in bone metabolism, the bioactivity of HA can be improved by adding small amounts of physiologically relevant ions into its crystal structure, with silicate-substituted HA (Si-HA) showing particularly promising results. Nevertheless, it remains unclear how distinct material characteristics influence the bioactivity due to the intertwined nature of surface properties. A co-culture methodology was optimised and applied for in vitro quantification of the biological response. Initially, HA and Si-HA samples were produced and characterised. To compare the bioactivity of the samples, a method was developed to measure interactions in an increasingly complex environment, first including fibronectin (FN) adsorption and subsequently cell adhesion in mono- and co-culture using primary human osteoblasts (hOBs) and human dermal microvascular endothelial cells (HDMECs), with- and without FN pre-coating. An experimental set-up was designed to assess to what extent different surface features of the samples contribute to the induced biological response. An 8 nm gold-sputter coating was applied to eradicate the electrochemical differences and polishing and abrading was used to reduce the differences in surface topographies. Overall, 1.25wt%Si-HA exhibited most nano-scale variations in surface potential. In terms of bioactivity, 1.25wt%Si-HA samples induced the highest osteoblast attachment and vessel formation. Additionally, in vitro vessel formation was established on Si-HA surfaces using a hOB;HDMEC cell ratio of 70:30 and a methodology was established that enabled the assessment of the relative effect of topographical and electrochemical features induced by silicon substitution in the HA lattice on their bioactivity. It was found that the difference in the amount of protein attached to HA and 1.25wt%Si-HA after 2 hours was affected by topographical differences. Conversely, electrochemical differences induced different vessel-like structure formation in co-culture with a FN pre-coating. Without a FN pre-coating, both topographical and electrochemical differences dictated the differences in angiogenic response. Overall, 1.25wt%Si-HA surface features appear to induce the most favourable protein adsorption and cell adhesion in mono- and co-culture with- and without FN pre-coating.

Machine Learning-Enabled Image Classification for Automated Electron Microscopy.

Traditionally, materials discovery has been driven more by evidence and intuition than by systematic design. However, the advent of "big data" and an exponential increase in computational power have reshaped the landscape. Today, we use simulations, artificial intelligence (AI), and machine learning (ML) to predict materials characteristics, which dramatically accelerates the discovery of novel materials. For instance, combinatorial megalibraries, where millions of distinct nanoparticles are created on a single chip, have spurred the need for automated characterization tools. This paper presents an ML model specifically developed to perform real-time binary classification of grayscale high-angle annular dark-field images of nanoparticles sourced from these megalibraries. Given the high costs associated with downstream processing errors, a primary requirement for our model was to minimize false positives while maintaining efficacy on unseen images. We elaborate on the computational challenges and our solutions, including managing memory constraints, optimizing training time, and utilizing Neural Architecture Search tools. The final model outperformed our expectations, achieving over 95% precision and a weighted F-score of more than 90% on our test data set. This paper discusses the development, challenges, and successful outcomes of this significant advancement in the application of AI and ML to materials discovery.

Cognitive dysfunctions in the course of SARS‑CoV‑2 virus infection, including NeuroCOVID, frontal syndrome and cytokine storm (Review).

During the coronavirus disease 2019 (COVID-19) pandemic, cognitive impairment of varying degrees of severity began to be observed in a significant percentage of patients. The present study discussed the impact of immunological processes on structural and functional changes in the central nervous system and the related cognitive disorders. The purpose of the present review was to analyse and discuss available information from the scientific literature considering the possible relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral infection and cognitive impairment, including NeuroCOVID, frontal syndrome and cytokine storm. A systematic literature review was conducted using: Google Scholar, Elsevier and the PubMed database. When searching for materials, the following keywords were used: 'cognitive dysfunctions', 'SARS-CoV-2', 'COVID-19', 'Neuro-SARS2', 'NeuroCOVID', 'frontal syndrome', 'cytokine storm', 'Long COVID-19'. A total of 96 articles were included in the study. The analysis focused on the characteristics of each study's materials, methods, results and conclusions. SARS-CoV-2 infection may induce or influence existing cognitive disorders of various nature and severity. The influence of immunological factors related to the response against SARS-CoV-2 on the disturbance of cerebral perfusion, the functioning of nerve cells and the neuroprotective effect has been demonstrated. Particular importance is attached to the cytokine storm and the related difference between pro- and anti-inflammatory effects, oxidative stress, disturbances in the regulation of the hypothalamic-pituitary-adrenal axis and the stress response of the body.

Orientation-dependent tunneling electroresistance in Pt/Pb(Zr,Ti)O3/Nb:SrTiO3 ferroelectric tunnel junctions

Orientation anisotropy is a well-known essential character for polarization characteristics of ferroelectric materials, which has been widely investigated in conventional ferroelectric random access memories. In this work, we study the effects of orientation on the tunneling electroresistance (TER) of ferroelectric tunnel junctions (FTJs). Rhombohedral Pb(Zr[Formula: see text],Ti[Formula: see text])O3 (PZT) that has the polar axis along the [Formula: see text] orientation is adopted as potential barriers and two kinds of FTJs that are composed of (001)- and (111)-oriented PZT barriers and Nb:SrTiO3 (Nb:STO) electrodes, respectively, are fabricated. The (111)-oriented Pt/PZT/Nb:STO FTJ exhibits a giant ON/OFF ratio of [Formula: see text], about 30 times that of the (001)-oriented device, due to the lowered PZT barrier in the ON state and the widen Schottky barrier in the OFF state based on current and capacitance analyses. In addition, compared to the (001)-oriented device, the (111)-oriented FTJ shows a sharper and faster switching between the ON and OFF states according to the nucleation-limited-switching dynamics model, giving rise to good linearity in memristive behaviors for synaptic plasticity and reliable retention and endurance properties for the resistance switching. The improved TER properties are ascribed to larger effective polarizations and 180∘ switching in the (111)-oriented PZT barrier. These results facilitate the design and fabrication of high-performance FTJ devices with the optimization of crystallographic orientation and polarization switching characteristics.

Performance analysis of self compacting concrete by incorporating fly ash, coal gangue powder, cement kiln dust and recycled concrete powder by absolute volume method

To achieve environmental sustainability and improve material characteristics, this study examines the performance of self-compacting concrete (SCC) that incorporates different industrial by-products, including fly ash (FA), coal gangue powder (CGP), cement kiln dust (CKD), and recycled concrete powder (RCP). Through an experimental program, the research evaluates the fresh and hardened properties of SCC as well as its microstructural features. Slump flow, T50, and V-funnel tests were utilized to evaluate the fresh characteristics, while the compressive strength was the main emphasis of the hardened property at 7, 14, and 28 days of curing periods. To clarify the internal structure of the material and the pozzolanic processes taking place therein, further microstructural investigations were carried out using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Due to pozzolanic reactions and the densification of the microstructure, the results show that adding these industrial by-products not only makes SCC more workable but also gradually increases its compressive strength. In particular, the study shows that combinations with FA, CKD, and RCP perform better than CGP in terms of flowability and strength development. The results highlight the technical advantages of improving concrete qualities through material innovation, in addition to the possible environmental benefits of recycling waste materials in construction.

Spatially Confined Microcells: A Path toward TMD Catalyst Design.

With the ability to maximize the exposure of nearly all active sites to reactions, two-dimensional transition metal dichalcogenide (TMD) has become a fascinating new class of materials for electrocatalysis. Recently, electrochemical microcells have been developed, and their unique spatial-confined capability enables understanding of catalytic behaviors at a single material level, significantly promoting this field. This Review provides an overview of the recent progress in microcell-based TMD electrocatalyst studies. We first introduced the structural characteristics of TMD materials and discussed their site engineering strategies for electrocatalysis. Later, we comprehensively described two distinct types of microcells: the window-confined on-chip electrochemical microcell (OCEM) and the droplet-confined scanning electrochemical cell microscopy (SECCM). Their setups, working principles, and instrumentation were elucidated in detail, respectively. Furthermore, we summarized recent advances of OCEM and SECCM obtained in TMD catalysts, such as active site identification and imaging, site monitoring, modulation of charge injection and transport, and electrostatic field gating. Finally, we discussed the current challenges and provided personal perspectives on electrochemical microcell research.

Reinforcing effects of ground tyre rubber on physical, mechanical, and thermal properties of polyethylene terephthalate

This study examines the use of waste and recyclable polyethylene terephthalate (rPET) along with micro-sized ground tire rubber (GTR) to produce a polymer matrix composite (PMC) material. The PMC materials are made in a Twin-screw extruder, with different ratios of rPET to GTR ranging from 90:10 to 50:50. In order to assess the performance of the newly created rPET-GTR matrix composite materials, the physical, mechanical properties are empirically observed. The thermal properties and crystallinity (Xc) of PMC materials are analysed using DSC. SEM and microscopic imaging are used to determine the characteristics of rPET-GTR composite materials, including elemental compositions like carbon, oxygen, and silicon. The functional group and chemical structure are confirmed through IR spectra analysis using FTIR techniques. The inclusion of micro-sized GTR has shown a significant effect on the physical (density = 1.306 - 1.208 g/cm3, water absorption = 1.76%–10.74%, and melt flow index = 8.12 - 12.79 gm/10 min), mechanical (tensile strength = 52.78 – 73.58 MPa, impact strength = 110.64 - 138.44 J/m, hardness = 56.14 - 76.37, and flexural modulus = 66.23 - 106.32 MPa), and thermal (melting temperature = 220.25°C–192.57°C, Xc = 20.30 to 30.58%) properties of rPET. These studies all work together to improve the performance of waste rPET and GTR materials by repurposing them. It helps to promote sustainability, cost-effectiveness, and expands the range of applications (automotive parts, building materials, sports equipment, electrical insulation and prosthetics) for rPET-based composites with potential uses in the polymer industries.

Effect of material characteristics of lead rubber isolators on seismic performance of box girder bridge

Near-field (NF) earthquakes have distinct ground motions, forward directivity pulses, and fling-step motions, causing structural responses to differ from far-field (FF) earthquakes. Seismic isolation is regarded as a developed and successful technology that may be applied to enhance a structure’s functionality and safeguard it against catastrophic earthquake effects. The variation in mechanical properties of seismic isolation also significantly influences bridge seismic response. The study investigates the influence of lead rubber (LRB) isolators and the characteristics of ground motions on seismically isolated bridges, aiming to determine optimal parameters for minimal earthquake response. Key parameters include ground motion characteristics, characteristic strength (Q), and isolator flexibility. The study modeled the force-deformation behavior of isolators using bilinear behavior, reflecting the Bouc-Wen hysteric model. CSI Bridge was used to model seismically isolated steel box girder bridges, with eight natural accelerograms assessing a 2% probability of exceedance in 50 years. The peak responses of pier displacement (MPD), isolator hysteric energy (HED), base shear, and deck acceleration are chosen as the response parameters for the comparison. To evaluate the response parameters, the earthquake data are scaled to the three studied peak ground acceleration (PGA) levels of design level (0.2 g), extreme level (0.4 g), and rare-extreme level (0.8 g). The findings offer insight on the relevance of isolator stiffness and its influences on the seismic performance of isolated bridges. The study identifies minimum values for pier displacement, hysteric energy, deck acceleration, and base shear at specific Q/weight sustained by isolator (W) and time period (T) values. Recommendations are made for the preliminary seismic isolation design of bridges with LRB isolators, highlighting the importance of PGV to PGA ratio in earthquake damage assessment.

Analysis of the recording of Fibonacci lenses on photopolymers with 3-D diffusion model

In this work a three-dimensional diffusion model is used to model photopolymers as a recording media. This model allows us to predict the properties of the Diffractive Optical Elements (DOEs) once we recorded into the photopolymer. This model had never been tested with more complex elements, such as multifocal diffractive lenses, as presented in the following in this work. In addition, the model includes; the estimation of the refractive index modulation, the low-pass filtering effect due to the experimental optical setup, and the evolution of the transverse intensity distribution. In this way, the selection of the appropriate material characteristics depending on the intended DOE application is made possible. Specifically, an acrylamide-based PVA/AA photopolymer is simulated using the proposed model. Moreover, coverplating and index matching systems are considered together to avoid the effects of thickness variation. Furthermore, in order to compare their properties using the proposed model, we focus on Fibonacci lenses (FL), a type of bifocal lenses. This allows us to evaluate the dependence of the focii intensity on the polymerisation rate, the diffusivity parameter, low-pass filtering effect and the use of the index matching system for these lenses. This enables us to know the recording parameters in order to produce this type of multifocal diffractive lenses with higher quality and precision.

When Structured Light Encounters Liquid Crystals

AbstractStructured light refers to the light field tailored by various degrees of freedom including intensity, phase, and polarization states in both spatial and temporal domains, which may greatly vitalize the technologies in both optics, such as the next‐generation optical communication as well as subwavelength imaging and the materials science in both fabrication and characterization. The structured characteristics of the structure light need materials also with structured optical properties that can generate or manipulate structured light in a straightforward way, which can be well satisfied by liquid crystals, a soft mater that can self‐assemble into tunable ordered structures through external stimuli. This review summarizes the research progress of the liquid crystal‐based devices used in structured light generations and modulations, including the well‐established techniques in the market, like the spatial light modulator, q‐plate and the liquid crystal integrated optical metasurfaces. Especially, light‐matter interactions are discussed from the topological view of both the structured light and the liquid crystal structures. Such a perfect matching in topology makes the liquid crystal a promising star together with structured light in future optic and photonic technologies.

Investigating Material Performance in Artificial Ankle Joints: A Biomechanical Study

This study delves into an in-depth examination of the biomechanical characteristics of various materials commonly utilized in the fabrication of artificial ankle joints. Specifically, this research focuses on the design of an ankle joint resembling the salto-talaris type, aiming to comprehensively understand its performance under different loading conditions. Employing advanced finite element analysis techniques, this investigation rigorously evaluates the stresses and displacements experienced by the designed ankle joint when subjected to varying loads. Furthermore, this study endeavors to identify the vibrating frequencies associated with these displacements, offering valuable insights into the dynamic behavior of the ankle joint. Notably, the analysis extends to studying random frequencies across three axes of motion, enabling a comprehensive assessment of directional deformities that may arise during joint function. To validate the effectiveness of the proposed design, a comparative analysis is conducted against the star ankle design, a widely recognized benchmark in ankle joint prosthetics. This comparative approach serves dual purposes: confirming the accuracy of the findings derived from the salto-talaris design and elucidating the relative efficacy of the proposed design in practical application scenarios.