Types Of Layers Research Articles

Convolutional Neural Networks: A Comprehensive Evaluation and Benchmarking of Pooling Layer Variants

Convolutional Neural Networks (CNNs) are a class of deep neural networks that have proven highly effective in areas such as image and video recognition. CNNs typically include several types of layers, such as convolutional layers, activation layers, pooling layers, and fully connected layers, all of which contribute to the network’s ability to recognize patterns and features. The pooling layer, which often follows the convolutional layer, is crucial for reducing computational complexity by performing down-sampling while maintaining essential features. This layer’s role in balancing the symmetry of information across the network is vital for optimal performance. However, the choice of pooling method is often based on intuition, which can lead to less accurate or efficient results. This research compares various standard pooling methods (MAX and AVERAGE pooling) on standard datasets (MNIST, CIFAR-10, and CIFAR-100) to determine the most effective approach in preserving detail, performance, and overall computational efficiency while maintaining the symmetry necessary for robust CNN performance.

Impact of graded CIGS absorber layer on Cd-free CIGS thin-film solar cell performance: numerical optimization

Abstract This paper investigates replacing the CdS buffer layer with (Zn, Mg)O and Zn(S, O) double buffer layers. To increase the efficiency of the structure, our strategy involves numerically studying and comparing three types of CIGS bandgap absorber layers: FB (Flat Band), Double Gradient Bandgap (DG) with a high bandgap near the Mo contact (back side), a low bandgap near the buffer layer (front side), and a minimum bandgap between them, and Simple Gradient Bandgap (SG) with a high bandgap near the Mo contact (back side) and a low bandgap near the buffer layer (front side). Each type features different linear graded profiles in the thickness direction to determine the optimal bandgap gradient of the CIGS layer. The performance of the three types is numerically analyzed using the SCAPS-1D simulator. Simulation enables us to test multiple structural combinations efficiently, saving both time and money, while providing results that guide experimental research. The proposed device structure is composed of the following layers: ZnO:Al/n-Zn1-xMgxO/n- ZnSxO1-x/p- Graded-CuIn1-xGaxSe2 /Mo. To study the effects of linear bandgap gradient distribution of Ga⁄((Ga+In) ) ratio according to the thickness direction on CIGS solar cell performance, the electrical properties of the proposed CIGS model were initially matched with experimental data to confirm the structure's accuracy. It was found that the Double Gradient Bandgap (DG), with maxima of 1.44 eV at the back side (near Mo contact), 1.238 eV at the front side (near n-type buffer layer interface), and a minimum of 1.154 eV at a position of 1.7 µm from the back side, has a higher efficiency than the other structures with 26.22% (Voc = 0.8134 V, Jsc = 37.82 mA/cm², FF = 85.21%). Optimizing the bandgap gradient of the CIGS absorber layer helps improve the efficiency of CIGS solar cells. 

New quaternary R2CoAl4Si2 compounds

Eight new R2CoAl4Si2 silicides (R = Y, Gd-Yb) were synthesized by arc melting, and their crystal structures were studied by X-ray powder diffraction. The compounds were found to adopt the same tetragonal structure type Tb2NiAl4Ge2 (Pearson symbol tI18, space group I4/mmm) and the cell parameters refined to: a = 4.09319 (6), c = 19.3431 (4) Å (R = Y), a = 4.1109 (3), c = 19.425 (2) Å (R = Gd), a = 4.09788 (8), c = 19.3616 (5) Å (R = Tb), a = 4.0850 (1), c = 19.2967 (8) Å (R = Dy), a = 4.07802 (2), c = 19.2575 (2) Å (R = Ho), a = 4.06871 (8), c = 19.2082 (5) Å (R = Er), a = 4.05836 (4), c = 19.1599 (4) Å (R = Tm), and a = 4.06627 (6), c = 4.06627 (6) Å (R = Yb). Isotypic compounds with R = Sm, Lu were not observed under the experimental conditions.The structure type Tb2NiAl4Ge2 is a quaternary variant of the prototype Yb3S2F4 ≡ (NiGe2)Tb2Al4. The structure of the R2CoAl4Si2 compounds can be described as a packing of monocapped square antiprisms [SiAl4R5] and cubes [CoAl8]. It can also be considered as formed by two types of layer containing cubes, stacked along the crystallographic direction [001]. One kind of layer is built of cubes of composition Al8, with every second cube centered by a Co atom, while the other kind of layer consists of slightly deformed empty cubes of composition R4Si4.

On the magnetic field of the oceans

The authors of the idea of linking strip magnetic anomalies with the formation of their sources under the influence of the Earth’s alternating magnetic field thought it possible to study the movement of lithospheric plates with their help. Most of them quickly abandoned such intentions. Nevertheless, most geophysicists in the world believe this is possible. The material accumulated over the 60 years of the idea’s existence contradicts it. The article reviews the currently known facts from the standpoint of plate tectonics and from the point of view of alternative ideas about the formation of the oceans and their crust. The discussion focuses on the spatial distribution and intensity of band anomalies of the oceans’ magnetic field and on their sources being restricted to certain types of rocks and layers of sections of the Earth’s crust and upper mantle. According to the author, they cannot be explained in any way by the plate tectonics concept. This conclusion is consistent with the long-standing results of many geophysicists. Recognition of this fact is restrained only by the unwillingness to abandon ingrained stereotypes. A variant of the process of oceanization of the continental crust proposed by the author, most of all reminiscent of continental endogenous regimes, reminiscent of rifting, accommodates models for the formation of band anomalies without involving sources with reverse magnetization. In oceanic basins, such sources have not been found at all. They occur in limited areas, but their experimentally determined parameters do not allow for an explanation of the observed magnetic field.

Probing enhanced superconductivity in van der Waals polytypes of VxTaS2

Layered transition metal dichalcogenides (TMDs) stabilize in multiple structural forms with profoundly distinct and exotic electronic phases. Interfacing different layer types is a promising route to manipulate TMDs' properties, not only as a means to engineer quantum devices but also as a route to explore fundamental physics in complex matter. Here we use angle-resolved photoemission (ARPES) to investigate a strong layering-dependent enhancement of superconductivity in TaS2, in which the superconducting transition temperature, Tc, of its 2H structural phase is nearly tripled when insulating 1T layers are inserted into the system. The study is facilitated by a vanadium-intercalation approach to synthesizing various TaS2 polytypes, which improves the quality of the ARPES data while leaving key aspects of the electronic structure and properties intact. The spectra show the clear opening of the charge density wave gap in the pure 2H phase and its suppression when 1T layers are introduced to the system. Moreover, in the mixed-layer 4Hb system, we observe a strongly momentum-anisotropic increase in electron-phonon coupling near the Fermi level relative to the 2H phase. Both phenomena help to account for the increased Tc in mixed 2H/1T layer structures. Published by the American Physical Society 2024

Multiscale Characterization of Fractures and Analysis of Key Controlling Factors for Fracture Development in Tight Sandstone Reservoirs of the Yanchang Formation, SW Ordos Basin, China

Tight sandstone reservoirs, despite their low porosity and permeability, present considerable exploration potential as unconventional hydrocarbon resources. Natural fractures play a crucial role in hydrocarbon migration, accumulation, and present engineering challenges such as late-stage reformation in these reservoirs. This study examines fractures in the seventh member of the Triassic Yanchang Formation’s tight sandstone within the Ordos Basin using a range of methods, including field outcrops, core samples, imaging and conventional logging, thin sections, and scanning electron microscopy. The study clarifies the characteristics of fracture development and evaluates the relationship between dynamic and static rock mechanics parameters, including the calculation of the brittleness index. Primary factors influencing fracture development were quantitatively assessed through a combination of outcrop, core, and mechanical test data. Findings reveal that high-angle structural fractures are predominant, with some bedding and diagenetic fractures also present. Acoustic, spontaneous potential, and caliper logging, in conjunction with imaging data, enabled the development of a comprehensive probabilistic index for fracture identification, which produced favorable results. The analysis identifies four key factors influencing fracture development: stratum thickness, brittleness index, lithology, and rock mechanical stratigraphy. Among these factors, stratum thickness is negatively correlated with fracture development. Conversely, the brittleness index positively correlates with fracture development and significantly influences fracture length, aperture, and linear density. Fractures are most prevalent in siltstone and fine sandstone, with minimal development in mudstone. Different rock mechanics layer types also impact fracture development. These insights into fracture characteristics and controlling factors are anticipated to enhance exploration efforts and contribute to the study of similar unconventional reservoirs.

Release of selected nutrients from polymer-coated fertilisers in the soil environment

The aim of the study was to evaluate the release of NH4-N and PO4-P from polymer-coated fertilisers in the soil environment, and to analyse their impact on pH and conductivity of the soil leachates. In this investigation mineral NPK(S) 6-20-30(7) fertiliser (as a starting material), commercial, controlled-release OsmocoteTM fertiliser (as a reference material) and four polymer-coated fertilisers have been used. Biodegradable polybutylene(succinate-co- dilinoleate), polyethylene(succinate-co-terepftalate) and chitosan have been used as coating materials. The experiments were conducted in the laboratory conditions, in PVC columns filled with air-dry soil. The nutrients release from the investigated materials was explained based on the diffusion mechanism and it was interpreted with the use of the Korsmeyer–Peppas kinetic model. Two mechanisms dominate in the release process of nutrients: the mechanism based on quasi-Fickian diffusion and non-Fickian (anomalous case) mechanism. The largest changes of pH and electrical conductivity (EC) of soil leachates occurred in the initial period of research for all tested fertilisers (pH: 9.5–20.3% – loamy sand (S1) 7.9–20.6% – sandy loam (S2); EC: 438–1667% – S1, 771–1509% – S2). The polymer coating significantly reduces the nutrient release from the fertiliser core. The size of these changes depends on the type and thickness of the polymer layer and the physicochemical properties of the soils.

Pengaruh Penambahan Zat Aditif Anti Striping (WETFIX-BE) Pada Kinerja Campuran Aspal Beton (AC-WC)

The asphalt concrete layer is the top layer of road pavement construction which is in direct contact with vehicle wheel loads and the influence of weather. One type of asphalt concrete layer is Asphalt Concrete – Wearing Course (AC–WC). Asphalt functions as an aggregate adhesive. In asphalt concrete mixtures it is very important to maintain its characteristics. During the maintenance period, the mixture will easily experience striping or peeling of the asphalt from the aggregate. To maintain and improve the properties of asphalt, one way is to use an anti-striping additive, this additive is Wetfix-Be, which is a compound that contains chemicals. Anti-peeling materials are only used if the residual Marshall stability value (IRS-Index of Retained Stability) or the Indirect Tensile Strength Ratio (ITSR) value of the asphalt mixture before adding the anti-peeling agent is less than required. If an anti-flaking agent must be used then before the anti-flaking agent is added to the mixture, the residual marshall stability (after 24 hour immersion, 60 °C) must be at least 75%.

Model test investigation on heat and deformation behaviors of canal slopes with protective layers caused by freeze-thaw action

Frost damage is one of the main factors affecting the stability of canal slopes in cold regions. To alleviate the damage, laying protective layers during the construction process has become an indispensable measure. In this study, two slope models were constructed using polyester geotextiles (slope I) and composite geomembranes (slope II) as the protective layer. Additionally, the insulation board in the control group were laid on specific section to examine their anti-frost effect. The temperature, frozen depth, and frost deformations of slope models during the freeze-thaw process were recorded and analyzed. Results suggest that the temperature of slope II is relatively lower than that of slope I in the freezing process. The temperature reduction at all monitoring sections of slope II are larger than that of slope I. The slope I exhibits a significant decrease in maximum frozen depth and maximum frost deformation. In particular, the section with the maximum frost deformation is independent of the type of protective layer, which all occurs in the middle of the slopes. The maximum frost deformations of slope models are 33.60 mm and 37.69 mm, respectively after laying the polyester geotextiles and composite geomembranes. Therefore, the polyester geotextiles have more advantages in reducing frost deformation than composite geomembranes. Additionally, if the insulation board and polyester geotextiles are laid together inside the slope, the maximum frost deformation can be further reduced to 9.72 mm. This study will help in the design and construction of canal slopes in cold regions.

Enhanced performance of perovskite solar cell by optimization of thin film control parameters using Taguchi method

The objective of the study is to examine the influence of various thin film control parameters on the synthesis of carbon-based passivated perovskite solar cells. Passivation additives, namely MOF UiO-66-NH2 (20mg/ml) and inorganic additive KPF6 (1mg/ml), were applied to treat the perovskite solar cells simultaneously. A PSC device of a standard configuration FTO/TiO2/Perovskite layer/Additives/HTL/Carbon electrode is utilized for experimentation. The performance evaluation of the system was carried out using Taguchi method. The critical control parameters considered in the study are: type of perovskite; annealing temperature of perovskite layer; the number of perovskite coating layers; and the type of hole transport layer (HTL). Each parameter is allocated three levels. An orthogonal array was designed using the Taguchi technique to optimize the quality control parameters. The signal-to-noise (S/N) ratio and analysis of variance (ANOVA) were then utilized to determine the ideal combination of parameters. The analysis identified the significant contribution of each parameter to the efficiency of perovskite cells. Among these parameters, the type of perovskite (used in the synthesis process) was found to impact the fabrication and performance of the cells significantly. Furthermore, it was observed that the type of hole transport layer (HTL) employed in the device significantly influences its performance. The best combination for our experiment is found to have FA0.55MA0.25Cs0.20PbI3 as the perovskite-type, an annealing temperature of 120˚C, a double layer of perovskite coating and Spiro-OMeTAD as the HTL. The solar cell is developed for each experiment as well as the validation test.

Modeling wear of different surface layers of agricultural tools in soil abrasive mass

Uniform quantitative measures have not been developed to identify the areas with the greatest intensification of tool wear. Therefore, this paper developed original approach to assess the wear of cutting elements by identifying the intensity of local volumetric wear. A tribological test was conducted under natural operating conditions in two soil types: sandy loam and loam. The specimens were mounted on a 9-tined cultivator with spring tines aggregated with an agricultural tractor. A method was developed to discretise the local volume changes of a component using surface scanning models developed from 3D scanning. The notion of the rake angle has been defined, allowing the assessment of changes in the shape of the element during wear. The practical usefulness of the developed method was verified on three types of surface layers, i.e. 38GSA steel, ELHARD70 deposited on it, and a G10 layer of carbide. For each of the tested variants, local volumetric consumption was defined based on the identification of the wear grid. These should be the basis for developing the technology of surface strengthening of elements. The work confirmed the complexity of the process of wear of working elements in natural soil conditions, presented in many research works. A different course of wear of the 38GSA steel and the Elhard 70 weld layer was shown, depending on the type of treated soil. In the case of samples made of G10 cemented carbide, the largest volumetric wear for heavy soil occurred outside the place of reinforcement application. The highest volumetric wear in the front zone was recorded for 38GSA steel in heavy soil. Wear results from the modelling are similar to those obtained from the experiment under natural conditions in light soil using the nominal model (CAD) and the actual friction surface.

Development Characteristics of Single Sand Body of Yan’An Formation in Western Ordos Basin

Abstract The precise characterization of the types and spatial distribution of strongly heterogeneous single sand bodies are a necessary prerequisite for the study of oil and gas reservoir formation. This article takes the Yan’an Formation in the western Ordos Basin as an example to systematically study the internal structure and profile distribution of strongly heterogeneous single sand bodies. The research results indicate that using mud interlayers, physical interlayers, and calcium interlayers as layered interfaces can effectively classify the single sand body types of each small layer in the Yan’an Formation. The drilling rate of a single sand body is between 50% and 85%, and the average number of sand layers is between 3 and 8. When two rivers intersect and are horizontally tangent, due to the mutual erosion of water flow, relatively thick sand bodies can be retained, ultimately resulting in a pattern of relatively thick on both sides and thin in the middle. The single sand body at the bottom is the most developed and has good continuity. In the transverse direction of the river, the continuity of a single sand body is relatively poor, and the extension range of a single sand body is 300m to 1200m. Along the river channel, single sand bodies are developed with good continuity, extending about 2km. The connectivity between the sand body and the well varies with the migration of the river in the transverse river profile of the research area. The lateral contact relationship of a single sand body determines the boundary of the river channel, and the profile characteristics of a single sand body also reflect its planar distribution. The intergranular pores of the Yan’an Formation sand body are relatively developed, and a large number of quartz particles offset the compressive stress of the rock. The corrosion of feldspar particles is relatively strong, retaining a large number of primary intergranular pores. There is a good quantitative relationship between the thickness of sand in a single level channel and the width of the channel. The control of the well network on the sand body is relatively small, and there is room for further densification of drilling. The vertical contact relationship of a single sand body in the Yan’an Formation of the research area can be divided into three modes: separation, stacking, and overlapping. Cut pile sand bodies with good connectivity have good production capacity. The different planar contact relationships reflect the degree of connectivity between channel sand bodies and wells, with lateral cutting type>docking type>isolation type. The side cut sand body has uniform longitudinal water absorption, small water absorption difference, and high-water drive degree. The isolation type has the greatest difference in water absorption rate and the lowest degree of water flooding.

Effect of mechanical vibration on microstructure and performance of Fe-based composite coatings fabricated by underwater laser deposition technology

To solve the problem of the uneven composition and poor performance caused by water environment during the underwater laser deposition process, the mechanical vibration assisted underwater laser deposition technology was innovatively proposed, and Fe-based composite layer was successfully prepared. The microstructure, grain type and properties of Fe-based composite layer with and without mechanical vibration were studied and compared. The results showed that the mechanical vibration broke the grain and promoted the formation of more nuclei, which reduced the average grain size by 13.48 %. The solute located in the grain gap was transferred to the liquid molten pool by mechanical vibration, which reduced the Ti content in the intergranular precipitated phase Fe2Ti and made the Fe2Ti from coarse continuous distribution to fine discontinuous distribution. Additionally, the mechanisms of mechanical vibration promoting the performance of the composite were analyzed comprehensively. Compared with the composite without mechanical vibration, the composite with mechanical vibration had good corrosion resistance after 30 days of immersion, and the tribo-corrosion resistance was also improved. With the aid of mechanical vibration, the ultimate tensile strength and elongation of the composite were increased by 11.30 % and 22.08 %, respectively, due to the formation of recrystallized grains, high density high-angle grain boundaries, and fine intergranular precipitate. This study was expected to provide a new way to regulate the microstructure and properties of the underwater laser deposition layer, and promote the application of underwater laser deposition technology in marine engineering equipment.

LSTM Recurrent Neural Network Based Method for Identification of PDC Drill Bit Operating Conditions and Its Application

Abstract PDC drill bit underground operating conditions identification is one of of the difficulties during the drilling operation. It is of great significant for the drilling improvement and accurate construction formation to accurately identify the complex operating conditions during drilling the operation such as PDC bit wearing and stick-slip vibration, etc. In this paper, data of relationship between torque, rate of penetration (ROP) signal and weight on bit (WOB), rev were obtained through lab simulation experiment, after which, a relationship database of torque, ROP signal and WOB, rev was established, a single-layer LSTM recurrent neural network (LSTM-RNN) was constructed, the number of neurons, batch size and optimizer type of LSTM layer were optimized. With BPTT algorithm, LSTM model was trained and tested on the training set containing 6000 groups of data, and achieved the goal of identifying the bit operation conditions against the input of WOB, torque, rev and ROP signal parameters. Based on this model, the PDC bit underground operating conditions identification software was compiled, and was connected to the logging unit to realize real-time identification of bit underground operating conditions, and field test application was successfully carried out in Mahu 1 Well Region. The research showed that the convergence speed was fast and the time cost was at the lowest when the number of neurons of LSTM model was 50, and that the optimized Adam optimizer model could meet the requirements of convergence speed and prediction accuracy with the lowest loss value. The classification accuracy of this model on the test set reached 94% and the accuracy of the prediction method was also verified by field test application. To sum up, the method of LSTM-RNN based PDC bit underground operating conditions real-time identification can better meet the requirements of accurate identification of PDC bit underground operating conditions in the practical drilling, and has guiding significance for the judgement of PDC bit operating conditions on site and formulation of scientific construction decisions.

Investigation of structural, dielectric, impedance, and conductivity properties of layered perovskites type compound: LiNdSnO4

Investigation of structural, dielectric, impedance, and conductivity properties of layered perovskites type compound: LiNdSnO4

SYNTHESIS AND PHYSICO-CHEMICAL PROPERTIES OF A NEW COMPLEX FERRITE

The article discusses the synthesis of new complex ferrite, radiographic and electron microscopic studies. The phase of complex ferrites was synthesized by the method of high-temperature sol-gel synthesis. For the first time, the structure of CrKFe2O5 Composite ferrite was studied by X-ray phase analysis and scanning electron microscope methods, the syngony type, elementary cell parameters, radiographic and pycnometric densities, and elemental analysis were determined. A comparative analysis of the relationship between the parameters of the Crystal cell of primary substances and the parameters of the obtained complex ferrite Crystal cell was carried out. Micro-samples were taken from different parts of the crystallite obtained through a scanning electron microscope, the elemental composition of the crystals was analyzed, and the general type of layer of the complex ferrite surface was demonstrated. As a result, the fact that the compound consists of two phases, the clarity of its construction was determined by the topography and chemical composition of the compound. As a result, it was found that the newly synthesized complex ferrite corresponds to the Formula CrKFe2O5. The particle size of the compounds formed is large (between 200 μm, 20.0 μm, 5.00 μm and 2.00 μm).

Nonlinear dynamic analyses of sandwich porous FG cylindrical shells with dual-layered FG porous cores

This research examines the nonlinear vibrations and dynamic postbuckling (DPB) analyses of sandwich porous functionally graded (SPFG) cylindrical shells with dual-layered FG porous (FGP) cores exposed to external excitation, using a semi-analytical method. The study investigates two types of FG layers: one with evenly distributed porosities (FG-EPD) and another with unevenly distributed porosities (FG-UEPD). It also studies the FGP cores in four configurations: one featuring symmetric porosity distribution with stiffening in the surface areas (SPD-Stiff), another with softening in the surface areas (SPD-Soft), a third with nonsymmetric porosity distribution (NSPD), and a fourth with uniform porosity distribution (UPD). Therefore, the SPFG cylindrical shells with dual-layered FGP cores with eight different configurations are investigated. Utilizing the classical shell theory (CST) alongside the geometrical nonlinearity in von Kármán–Donnell framework, and Galerkin’s method, this study addresses the nonlinear dynamic problem. An approximate solution for the deflection shape using three terms is selected, and the relationship between frequency and amplitude in nonlinear vibration is clearly defined. The nonlinear dynamic behaviors including vibration and DPB responses are examined using the P-T method, which is named for its use of the piecewise constant argument in conjunction with the Taylor series expansion. The critical dynamic buckling load of SPFG cylindrical shells with dual-layered FGP cores is investigated via the Budiansky–Roth criterion.

Seismic performance of FRP-repaired RC piers after blast loading

Aiming to evaluate the effectiveness of fiber-reinforced polymer (FRP) repair on the seismic performance of blast-damaged reinforced concrete (RC) piers, the field test and numerical simulation were conducted. Firstly, a successive field explosion test, carbon FRP (CFRP) repair, and lateral cyclic loading test were performed on two 1/2-scale RC pier specimens. The test data including the incident overpressure-time histories of blast wave, damage profiles and lateral force-displacement relationships of pier specimens, etc. were comprehensively recorded and discussed. By comparing with the previous blast-damaged pier specimen, the negative maximum force and ductility of CFRP-repaired pier were increased by 97 % and 44.9 % after 1.0 kg TNT explosion, respectively. Then, an integrated numerical simulation approach based on explicit-implicit switching and full restart algorithms was proposed and validated in predicting the dynamic and quasi-static behaviors of RC piers under successive blast loading, CFRP repair, and lateral cyclic loading. Finally, a prototype RC pier was designed and the suicide vest bomb (TNT equivalence of 9 kg) specified by the Federal Emergency Management Agency was selected as the threat of contact explosion. The influences of FRP type, repair height, and number of FRP layer on restoring the seismic performance of the blast-damaged pier were further discussed. It indicates that, (i) CFRP is more effective than glass FRP and aramid FRP; (ii) increasing the repair height could not significantly improve the seismic performance of pier; (iii) the number of FRP layer has significant effect, e.g., the positive and negative maximum forces after 4-layer CFRP repair are improved by 9.4 % and 45.3 % compared to the unrepaired pier, respectively. The present study could provide a helpful reference for assessing the FRP repair effectiveness on the seismic performance of blast-damaged RC bridge piers.

The effects of Nb on the microstructure and performance of laser-cladded Fe50-xMn30Co10Cr10Nbx high entropy alloy coatings

A laser cladding technique was employed to produce a Fe50-XMn30Co10Cr10NbX (X = 2.5, 5, 7.5, 10at%) high entropy alloy coating. This study delved into the influence of Nb concentration on the coating’s phase constitution, microstructural features, hardness, and wear resistance. The high entropy alloy coating exhibited a multifaceted structural composition, encompassing FCC (Face-Centered Cubic), HCP (Hexagonal Close-Packed), and BCC (Body-Centered Cubic) structures, along with the presence of Laves phase. Notably, the incorporation of Nb led to an augmentation in the Laves phase and modifications within the microstructure. The hardness of the cladding layer is higher than that of the substrate. With the increase of Nb content, the hardness of the cladding layer increases first and then decreases; the average hardness of the Fe42.5Mn30Co10Cr10Nb7.5 cladding layer is the highest, the maximum hardness is 429.8Hv, and the average hardness is 382.3Hv. The friction coefficient and weight loss of the cladding layer decreases first and then increases with the increase of Nb content. The friction coefficient and weight loss of the Fe42.5Mn30Co10Cr10Nb7.5 cladding layer are the smallest, which are 0.0132 g and 0.5974, showing the best wear resistance. The wear types of high entropy alloy cladding layer are both adhesive wear and abrasive wear. The addition of Nb into high entropy alloy will form the Laves phase, which can improve the mechanical properties of high entropy alloy.

Influence of bolt preload of anchors on bond-slip behavior of fiber fabric-steel interface

Bond-slip behavior is a common failure mode in steel structures reinforced with fiber fabric. Premature debonding of the fiber fabric significantly impacts the effectiveness of steel structure reinforcement. In this study, a gripping anchor is proposed to enhance the reliability of the interface between fiber fabric and steel plates. Experimental investigations were conducted to analyze the influence of anchor bolt preload on the double shear joint between fiber fabric and steel plates. 41 specimens were prepared and tested to explore the effects of parameters such as bolt preload, anchor position, number and type of fiber fabric layers, and bond length on load-bearing capacity. Comparative analyses were conducted on failure modes, ultimate loads, and stress-strain distributions of the specimens. Experimental results indicate that the position of the anchor has a minimal impact on the ultimate bearing capacity of the specimen. However, anchors positioned closer to the joint end exhibit lower ductility upon failure. A novel predictive model was developed to characterize the bond-slip behavior of preload applied to carbon fiber fabric and steel plates. The theoretical model of the ultimate bearing capacity in the yield stage fits well with the experimental results of specimens with three layers of carbon fiber fabric, with a difference range of 0.34 % to 14.97 % compared to actual results. This indicates that the model has high accuracy in predicting stress-strain and bearing capacity.