Properties Of Layers Research Articles

In-situ characterization of dynamic electromechanical properties for PVC gel actuators

PVC gel actuator possesses the advantages including low driving voltage, substantial deformation, and high output force, making it ideal for applications in micro-lenses, assistive rehabilitation, and soft robotics. However, there remains a lack of in-situ characterization and quantitative analysis of plasticizer migration and charge transfer within PVC gel, resulting in an unclear understanding of changes in the plasticizer content, mechanical and electrical properties of the enrichment layer. In this study, we conducted in-situ characterization of plasticizer migration and charge transfer within PVC gel, and analyzed the change of plasticizer content, mechanical and electrical properties. In-situ Raman spectroscopy results revealed that plasticizer migration takes time to reach equilibrium, resulting in a gradient distribution of plasticizer content within the enrichment layer. Furthermore, in-situ broadband impedance analysis demonstrated that stimulation voltage induces changes in the material's electrical properties, transitioning from uniform electrical characteristics to distinct properties between the gel layer and the enrichment layer. Notably, we established a mathematical relationship between modulus and plasticizer content, revealing a gradient distribution of modulus within the enrichment layer. This study not only contributes to understanding the underlying mechanisms of mechanical and electrical properties variations within PVC gel, but also provides valuable insights for optimizing the actuation performance of PVC gel actuators.

Repairing weld for directly solidified Ni-based superalloy substrates using directed energy deposition of Inconel 625

Although the maintenance, repair, and operation of gas turbine systems are important issues in enhancing the operation of power units, advanced welding repair processes have limitations in depositing directionally solidified Ni-based superalloy components. To overcome this problem, in this study, a directed energy deposition method was applied to repair directionally solidified components using an Inconel 625 alloy. The rapid cooling rate and small laser beam diameter during directed energy deposition minimized the heat-affected zone and duration in the mushy zone, resulting in crack inhibition at the interface. The first laser scan partially melted the substrate and formed a mixing zone with a chemical composition gradient. By combining the chemical compositional gradient and dislocation accumulation due to repetitive solidification, that is, with the melting cycles of directed energy deposition, the thermal stability decreased, resulting in recrystallization and grain growth in the mixing zone. Consequently, the crack-free continuous interface of the partially repaired components did not induce tensile fracture near the interface. Although the mechanical properties of the IN625 deposit layer were degraded by severe heat treatment of the substrate, the results demonstrated that energy deposition with post-heat treatment is an effective approach in repairing Ni-based superalloy components without cracks and inclusion initiation.

Evaluation of anode support microstructure in solid oxide fuel cells using virtual 3D reconstruction: A simulation study

In this study, the impact of microstructural properties of the anode support layer (ASL) composed of catalyst, electrolyte and pore phases on the performance of solid oxide fuel cell (SOFC) is investigated. Synthetic SOFC anode microstructures, comprising two layers including the anode functional layer (AFL), where electrochemical reactions take place, are generated using an open-source software. Different configurations of the anode support layer with various particle sizes and volume fractions of the catalyst and electrolyte phases for different porosities are combined with a consistent AFL to isolate the effect of ASL microstructural parameters. The triple phase boundary (TPB) density, chosen as a useful metric monitoring the anode performance, is then quantitively determined for each anode layer and entire anode in all reconstructed microstructures. The results demonstrate that the microstructure of ASL significantly influences the anode and thus cell performance by impacting reactant gas supply and current collection, emphasizing the necessity for meticulous design. Specifically, ASL microstructures with low volume fractions of Ni and the pore phase, and/or substantial differences between the volume fractions of the phases, are observed to result in discontinuous phase networks, which deactivate TPBs in AFL.

Effect of Pinless Friction Stir Processing on Microstructure and Properties of Surface Modification Layer of 2024 Aluminum Alloy

Abstract Friction stir processing (FSP) is an advanced material surface modification technology that is both green and energy-efficient. This technology plays a crucial role in regulating the surface microstructure of alloys and improving their material surface properties. It achieves this through the synergistic effect of non-equilibrium thermodynamics and surface mechanical deformation. In this work, the surface modification of an aluminum alloy was performed using pin-less FSP. And the modified surface was then analyzed using stress-strain curves, optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical tests to investigate the impact of spindle velocity on the modified layer's properties. Results of the study show after undergoing pin-free FSP modification treatment, the surface of the alloy appears bright and flat. The modified layer displays refined grains and numerous dispersed second-phase particles. Furthermore, the grains in the modified layer exhibit a gradient distribution from the surface to the matrix. Regarding the properties, Compared to the base material (BM), the yield strength (σ0.2) and tensile strength (σb) of the alloy-modified layer were increased by 34.8% and 29.4%, respectively. The maximum elongation (δ) of the modified coating reached 22.3%. The modified layer exhibits a tough-brittle mixed fracture pattern. Additionally, the modified layer's corrosion resistance significantly improves. The performance of the modified coating shows the most significant improvement when the spindle speed reaches 1000 rpm. The study aims to explore the effect of spindle speed on the properties of alloy-modified layers produced by FSP without a stirring pin. This research could be used to create superior metal matrix composites by adding reinforcement particles.

Seismic Inversion Techniques and Attribute Analysis for Accurate Well Placement in Offshore Niger Delta Basin, Nigeria

Before this study, simple methods like seismic attribute analysis have often been used for reservoir characterization with successes however, there is still the need to reduce exploration uncertainty to a negligible level and boost investors’ confidence. This study integrated seismic inversion with seismic attribute analysis to better characterize the reservoirs in MTW Field in deep-offshore Niger Delta Basin. Five (5) wells with complete suite of petrophysical logs, three-Dimensional (3-D) seismic data, checkshot and other well information were used. The well data were thoroughly quality checked, reservoirs were litho-stratigraphically delineated and used for petrophysical analysis across the wells. This was followed by seismic-to- well-tie, seismic interpretation, and seismic attribute analysis (Root Mean Square-RMS) generated using depth surface maps. 3-D static reservoir model and volumetric evaluation were carried out. Petrophysical properties were derived and distributed across the 3-D static model using sequential gaussian simulation algorithm to ascertain shale volume spread across the model. To improve the seismic resolution and reduce interpretation uncertainty at greater depth, model- based post-stack seismic inversion was performed to obtain acoustic impedance cube. Litho-stratigraphic and petrophysical analysis result revealed five reservoir sands (A, B, C, D, and E). Reservoir-A was seen to be more viable with a thickness of 13.42 m, high effective porosity of 27%, permeability of 3187.53 mD, low water saturation of 34% and low shale volume of 11% which are indication good reservoir quality and producibility. The seismic interpretation revealed thirty-one (31) growth and antithetic faults oriented in the NE-SW and NW-SE directions, respectively. The RMS result revealed high amplitude reflectivity which is a measure of zone of interest. Based on this, seven (7) prospects and three (3) leads were identified. The seismic inversion result shows a high level of accuracy with a correlation coefficient of 0.997; 0.997; 0.995; and 0.996 in MTW-001, MTW-003ST1, MTW-004ST1 and MTW-005 wells, respectively. The acoustic impedance successfully resolved and improved on the resolution of the seismic stacking velocity especially at reservoir layers and at depth deeper than 3600 ms. Acoustic impedance as a layer property has improved on the lateral and vertical resolutions of the data beyond what the usual seismic interval velocity could image thus, validating some of the prospects and leads identified in this study. This demonstrated that uncertainty can be reduced by a blend of RMS and seismic inversion in identifying reservoir for accurate placement of wells. It is therefore recommended that E and P operators should adopt the technique in their future hydrocarbon exploration endeavor in frontier and matured basins.

Optimizing Geometry and ETL Materials for High-Performance Inverted Perovskite Solar Cells by TCAD Simulation.

Due to the optical properties of the electron transport layer (ETL) and hole transport layer (HTL), inverted perovskite solar cells can perform better than traditional perovskite solar cells. It is essential to compare both types to understand their efficiencies. In this article, we studied inverted perovskite solar cells with NiOx/CH3NH3Pb3/ETL (ETL = MoO3, TiO2, ZnO) structures. Our results showed that the optimal thickness of NiOx is 80 nm for all structures. The optimal perovskite thickness is 600 nm for solar cells with ZnO and MoO3, and 800 nm for those with TiO2. For the ETLs, the best thicknesses are 100 nm for ZnO, 80 nm for MoO3, and 60 nm for TiO2. We found that the efficiencies of inverted perovskite solar cells with ZnO, MoO3, and TiO2 as ETLs, and with optimal layer thicknesses, are 30.16%, 18.69%, and 35.21%, respectively. These efficiencies are 1.5%, 5.7%, and 1.5% higher than those of traditional perovskite solar cells. Our study highlights the potential of optimizing layer thicknesses in inverted perovskite solar cells to achieve higher efficiencies than traditional structures.

Development of a Methodology Based on Optical Interferometry for Measuring Fibrinolytic Activity.

Fibrinolytic activity assay is particularly important for the detection, diagnosis, and treatment of cardiovascular disease and the development of fibrinolytic drugs. A novel efficacious strategy for real-time and label-free dynamic detection of fibrinolytic activity based on ordered porous layer interferometry (OPLI) was developed. Fibrin or a mixture of fibrin and plasminogen (Plg) was loaded into the highly ordered silica colloidal crystal (SCC) film scaffold to construct a fibrinolytic response interference layer to measure fibrinolytic activity with different mechanisms of action. Fibrinolytic enzyme-triggered fibrinolysis led to the migration of interference fringes in the interferogram, which could be represented by optical thickness changes (ΔOT) tracked in real time by the OPLI system. The morphology and optical property of the fibrinolytic response interference layer were characterized, and the Plg content in the fibrinolytic response interference layer and experimental parameters of the system were optimized. The method showed adequate sensitivity for the fibrinolytic activity of lumbrokinase and streptokinase, with wide linear ranges of 12-6000 and 10-2000 U/mL, respectively. Compared with the traditional fibrin plate method, it has a lower detection limit and higher linearity. The whole kinetic process of fibrinolysis by these two fibrinolytic drug models was recorded in real time, and the Michaelis constant and apparent kinetic parameters were calculated. Importantly, some other blood proteins were less interfering with this system, and it showed reliability in fibrin activity detection in real whole blood samples. This study established a better and more targeted research method of in vitro fibrinolysis and provided dynamic monitoring data for the analysis of fibrinolytic activity of whole blood.

Experimental study on comprehensive detection technology of shallow gas in deep soft soil layer

This study focuses on the underground shallow gas detection project in the Lingkun Island area of the northern entrance tunnel of the Wenzhou City Light Rail S2 line. Based on geological exploration data of shallow gas, we chose the technique of controlled-release gas with static pressure as the experimental foundation, integrating various technologies such as multi-functional in-situ probing, electrical methods, and seismic waves, comprehensively researching shallow gas detection technology in the Lingkun Island area. We conducted field probing experiments to accurately obtain the physical and mechanical properties of gas-rich soil layers and further studied the possibility of determining gas-rich locations. By applying parallel electrical methods, we can accurately identify and distinguish areas of anomalous resistivity in shallow geological structures. Based on abnormal changes in acoustic impedance in strata, we used seismic wave methods, including seismic CT and seismic wave scattering technology, to accurately reveal the presence and depth of shallow gas, providing reliable basis for accurate determination of shallow gas. Finally, we summarized a comprehensive plan for underground shallow gas detection technology, covering on-site data collection, data processing, and image interpretation of results, which will provide valuable references for future shallow gas exploration in relevant areas.

Electrical properties of unintentionally doped β-Ga2O3 (010) thin films grown by a low-pressure hot-wall metalorganic chemical vapor deposition

We investigated the electrical properties of unintentionally doped (UID) Ga2O3 (010) layers grown by low-pressure hot-wall metalorganic chemical vapor depositions from device characteristics of Schottky barrier diodes (SBDs) fabricated on them. Highly resistive properties of the UID Ga2O3 layers were confirmed from current–voltage characteristics. The specific on-resistance of the SBD with the most resistive UID Ga2O3 layer was 2.2 × 107 Ωcm2. Capacitance–voltage characteristics revealed that most of the SBDs had complete depletion of the UID layers at thermal equilibrium, indicating that their residual effective donor densities were less than 3.0 × 1013 cm−3.

Advanced multi-image segmentation-based machine learning modeling strategy for corrosion prediction and rust layer performance evaluation of weathering steel

Corrosion images are the most accessible type of data to collect. To utilize these data to monitor and evaluate the corrosion of weathering steel (WS) efficiently. This study established a dataset of corrosion images of WS by accelerated corrosion experiments with dry and wet cycles. Image segmentation algorithms and machine learning were used for training, modeling, and data mining of the image data. The results showed that 22 features in the corrosion images were highly correlated with the corrosion thickness loss, with the highest correlation coefficient exceeding 0.7. The rust layer texture and color features showed a synergistic evolution during the corrosion process. On this basis, a classification model of the rust layer was developed to quantify the evolution of the protective properties of the rust layer during the corrosion process. In addition, the established integrated learning model achieves accurate prediction (R2 > 0.94) for WS corrosion thickness loss.

A purine derivative for the modulation of the corrosion behavior of nickel aluminum bronze in seawater: a comprehensive and in-depth investigation on the corrosion inhibition mechanism

6-mercaptopurine (SMP), recognized for its biological activity, is investigated for its corrosion inhibition mechanism on nickel-aluminum bronze (NAB) in seawater, demonstrating a high efficiency of 99.6%. The physical adsorption of SMP on the NAB surface contributes to the multilayer structural arrangement of SMP. The Cu+-SMP complex is generated on the surface of NAB, which possesses a corrosion protection effect. SMP alters the semiconductor properties of corrosion product layer and reduces the carrier concentration. SMP can adsorb better on uncorroded NAB surfaces. This study holds significant importance in unraveling the mechanisms behind the corrosion behavior of NAB surfaces regulated by SMP.

Influence of borax on the structure and tribological properties of aluminum alloy plasma electrolytic fluorination film layer

In recent years plasma electrolytic fluorination (PEF), as an emerging surface treatment technology, has been widely used to prepare fluorinated layers on metal surfaces. In this paper, different concentrations of borax are used as additives for plasma electrolytic fluorination of 6061 aluminum alloy. The effect of borax on the discharge characteristics of ion plasma electrolytic fluorination, as well as the coating growth process and the evolution of the tissue structure are systematically investigated. The results show that the surface of the coating prepared by adding a quantitative amount of borax is smoother and flatter, and at the same time has better abrasion and corrosion resistance, so it has a wide range of application prospects in the engineering field.

Elaboration of spinel Co3O4 via cost-effective chemical spray pyrolysis for enhanced photo-response

Co3O4 thin layers were produced through spray pyrolysis, varying the spray duration from 10 to 25 minutes. Various characterizations were employed to explore the impact of spray durations on the sprayed layers properties. They exhibited a cubic structure with strong preferred orientation along the (111) direction. Morphological analysis indicated a good morphology as the duration increased. Compositional analysis confirmed the predominant presence of Co and O in the growing layer. Optical properties revealed an augmentation in absorption with prolonged duration. The band-gap energy decreased from 1.45 to 1.40 eV for durations from 10 to 20 minutes. The optical and electrical properties were influenced by duration. Notably, Co3O4 (20 minutes) exhibited a significant variation in resistance between light ON and OFF. These findings highlight the ability to tailor the properties of Co3O4 compound by optimizing the spray duration for the effective fabrication of photo-sensors.

Modeling and Laboratory Investigation of Tack Coats as Bituminous Pavement Interlayer

The adhesive properties of tack coats between asphalt pavement layers are crucial for the pavement’s structural behavior. This study first involved numerical analyses to compare stress patterns, deformations, and displacements in the pavement structure under various geometric and mechanical conditions. A rational calculation method based on the theory of elastic multilayer systems was used to quantify the impact of layer properties such as thickness, stiffness modulus, and Poisson’s ratio on interlayer bonding. Three bonding conditions—Full Friction, Partial Bonding, and Full Debonding—were analyzed to understand the tack coat’s effect between the top two layers. The second phase involved characterizing the mechanical behavior of the interface through shear strength tests (Leutner shear test) on both laboratory-prepared specimens and samples from a 10-year-old highway. Specimens were prepared using a Roller Compactor and tested under different interface conditions: hot-on-hot (H/H), residual bitumen 200 g/m2 (RB 200), and residual bitumen 400 g/m2 (RB 400). The tests examined the bonding effects in terms of tangential force and shear displacement at failure, as well as the impact of vehicular traffic on rutting and fatigue failure. Finally, this study investigated the long-term aging effects of the binder on interlayer bonding and sought to correlate the results of numerical calculations with those of the laboratory tests.

Analysis of image formation in optical palpation.

Optical palpation is an emerging elastography technique that generates two-dimensional images of mechanical stress at the tissue surface, with clinical applications such asintraoperative cancer detection and scar assessment. It has been implemented using various imaging systems, however, an analysis of how deformation of the sample and layer influences image formation has not been performed. Here, an analysis framework is presented, which assesses performance independently of the imaging system used. Optical palpation of varying samples and layers is simulated using finite element analysis and validated with experiments on silicone phantoms, providing a characterization of detectability, feature resolution, and contrast ratio. Using our framework, we demonstrate that computational optical palpation, which incorporates realistic assumptions of layer deformation, improves the feature resolution up to a factor of four. This framework can guide the development of optical palpation and aid in the selection of appropriate imaging system and layer properties for a given application.

Ultrafine Grain 316L Stainless Steel Manufactured by Ball Milling and Spark Plasma Sintering: Consequences on the Corrosion Resistance in Chloride Media

This paper reports experimental results concerning the corrosion of 316L austenitic stainless steels produced by ball milling and spark plasma sintering in NaCl electrolyte. Specimens with grain sizes ranging from 0.3 µm to 3 µm, without crystallographic texture, were obtained and compared with a cast that is 110 µm in grain size and an annealed reference. The potentiodynamic experiments showed that the reduction in grain size leads to a degradation of the electrochemical passivation behavior. This detrimental effect can be overcome by appropriate passivation in a HNO3 concentrated solution before consolidation. The Mott–Schottky measurements showed that the semiconducting properties of the passive layer do not vary significantly on the grain size, especially the donor density, which is responsible for the chemical passivation breakdown by chloride anions. The total electrical resistance of the layer, measured by impedance spectroscopy is always lower than the one of a cast and annealed 316L, but it slightly increases with a reduction in grain size in the ultrafine grain range. This is followed by a slight increase in the thickness of the oxide layer. The effect of chloride ions is very pronounced in terms of passivation breakdown if the powder is not passivated prior to sintering. This leads to the nucleation and growth of subsurface main pits and the formation of secondary satellite pits, especially for the smallest grain sizes. Passivation of the 316L powder before sintering has been found to be an effective way to prevent this phenomenon.

Effect of VC content on the microstructure, ablation and oxidation resistance of the protective oxide layer of C/C-ZrC-VC-SiC composites

A third reinforcement vanadium carbide (VC) is introduced to improve the compactness, ablation and oxidation resistance of the protective oxide layer of C/C-ZrC-SiC composites, and the effect of VC content on the microstructure and properties of the oxide layer is studied. Results showed that the compactness of the oxide layer gradually increased with the increase of VC content. Excessive oxide melt leaded to an increase in the evaporation and mechanical erosion. Z2V1S6 exhibited the best ablation and oxidation resistance, which was attributed to the formation of a tightly bound composite oxide bi-layer with a dense ZrO2-SiO2-V2O3 inner layer and a ZrO2 skeleton outer layer bonded by SiO2-V2O3 melt.

Effects of structure parameter and material property on thermal performance of on-board hydrogen storage tanks during fast refueling

As a power generation fuel, high-pressure hydrogen gas is widely used in transportation, and significantly contributed to development of hydrogen fuel cell electric vehicles. However, obvious temperature rise generated during fast refueling causes serious safety risk to reliable operation of fuel cell stacks. Therefore, it is necessary to conduct in-depth research on fast filling process. Based on safety reasons, the SAE J2601/ISO 15869 strictly regulates the maximum temperature limit of 85 °C in specifications for refueling hydrogen gas tanks. In this study, a 70 MPa, Type IV on-board hydrogen storage tank is adopted as the research object, and a 2-dimensional axisymmetric numerical model is established to study the temperature rise of the vapor within storage tanks during fast refueling. The Realizable k-ε turbulence model is employed to simulate high intensity turbulent fluctuation during fast filling. Considering the compressibility of vapor, the state of equation for real hydrogen gas is used by obtaining fluid thermodynamic properties from the National Institute of Standards and Technology database. Three groups of fast filling experiments are selected to validate the developed numerical model. The comparison result shows that the numerical model has good prediction ability on hydrogen fast refueling. The final mass average temperature differences between numerical results and experimental data are 2.6 K, 4.3 K, and 0.03 K, respectively. Based on the developed numerical model, the influences of structure parameters and material properties on the temperature rise of hydrogen storage tanks are investigated. The results indicate that the inlet diameter and wall thickness of the inner and outer layers of the storage tank have weaken impacts on the temperature rise during rapid charging, with the maximum temperature differences of 1.8 K, 0.74 K, and 0.54 K, respectively. Due to the influence of heat capacity, the material properties of different layers exhibit a similar variation trend. This work can deepen researchers' understanding of the temperature rise of on-board hydrogen storage tanks during fast filling, and provide technical references for the structural optimal design of tanks and rapid refueling at hydrogen stations.

MoS2 augmentation in CZTS solar cells: Detailed experimental and simulation analysis

This study investigates the optimization of CZTS-based thin-film solar cells through the incorporation of MoS2 as an interfacial layer. Using SCAPS-1D simulation software, we analyzed the effects of layer thicknesses, carrier concentrations, and defect densities on device performance. The optimized CZTS (100 nm)/ MoS2(1000 nm)/ CdS(100 nm)/ ZnO(50 nm) structure demonstrated a significant efficiency increase to 19.01 % compared to 17.03 % for the CZTS (1100 nm)/ CdS(100 nm)/ ZnO(50 nm) cell. Key improvements include enhanced charge generation, quantum efficiency, and balanced carrier transport.Materials were synthesized using microwave-assisted methods and characterized by XRD and UV–vis spectroscopy. XRD confirmed the desired crystal structures, while optical bandgaps of 1.5 eV (CZTS), 1.3 eV (MoS2), 2.4 eV (CdS), and 3.3 eV (ZnO) were determined. Practical solar cells were fabricated using spin-coating techniques, with thicknesses of CZTS (122 nm)/ MoS2 (1038 nm)/ CdS(130 nm)/ ZnO(94 nm). While showing improved performance with the MoS2 layer, efficiencies were lower than simulated values due to fabrication-related defects. The best experimental cell achieved 1.89 % efficiency, compared to 1.38 % without MoS2.This research demonstrates the potential of MoS2 as an effective interfacial layer in CZTS solar cells, providing insights into optimizing layer properties for enhanced performance. The study also highlights the challenges in translating simulated improvements to practical devices, emphasizing the need for advanced fabrication techniques to minimize defects and maximize efficiency.

Modulating Neuromorphic Behavior of Organic Synaptic Electrolyte-Gated Transistors Through Microstructure Engineering and Potential Applications.

Organic synaptic transistors are a promising technology for advanced electronic devices with simultaneous computing and memory functions and for the application of artificial neural networks. In this study, the neuromorphic electrical characteristics of organic synaptic electrolyte-gated transistors are correlated with the microstructural and interfacial properties of the active layers. This is accomplished by utilizing a semiconducting/insulating polyblend-based pseudobilayer with embedded source and drain electrodes, referred to as PB-ESD architecture. Three variations of poly(3-hexylthiophene) (P3HT)/poly(methyl methacrylate) (PMMA) PB-ESD-based organic synaptic transistors are fabricated, each exhibiting distinct microstructures and electrical characteristics, thus serving excellent samples for exploring the critical factors influencing neuro-electrical properties. Poor microstructures of P3HT within the active layer and a flat active layer/ion-gel interface correspond to typical neuromorphic behaviors such as potentiated excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), and short-term potentiation (STP). Conversely, superior microstructures of P3HT and a rough active layer/ion-gel interface correspond to significantly higher channel conductance and enhanced EPSC and PPF characteristics as well as long-term potentiation behavior. Such devices were further applied to the simulation of neural networks, which produced a good recognition accuracy. However, excessive PMMA penetration into the P3HT conducting channel leads to features of a depressed EPSC and paired-pulse depression, which are uncommon in organic synaptic transistors. The inclusion of a second gate electrode enables the as-prepared organic synaptic transistors to function as two-input synaptic logic gates, performing various logical operations and effectively mimicking neural modulation functions. Microstructure and interface engineering is an effective method to modulate the neuromorphic behavior of organic synaptic transistors and advance the development of bionic artificial neural networks.