Layered Plates Research Articles

Improved Adhesion of Direct Copper Seed Layer by Medium-Vacuum Sputtering Using Vacuum Ultraviolet Light

A sputtering method is used to form the seed layer for copper electric plating. In general, copper sputtering has weak adhesion to resin, so titanium sputter is combined to increase the adhesion strength. However, etching in the lithography process requires two types of processes, titanium and copper metal. Adhesion strength was improved by performing vacuum ultraviolet (VUV) treatment as a pretreatment for medium-vacuum sputtering. We discovered the relationship between the hydroxyl groups on the resin surface and the adhesion strength by the chemical modification XPS method. Furthermore, by XPS analysis of the peeled copper interface, the adhesion mechanism between the resin and copper due to VUV irradiation was estimated. We evaluated the absorption properties in the vacuum ultraviolet region of a thinly polished glass epoxy resin. We investigated the behavior of functional groups at the interface and considered the effect of vacuum ultraviolet light in the depth direction.

Innovative deep eutectic solvent approaches in zinc electroplating for morphology enhancement, superior strength, and corrosion protection

The growing number of galvanized scrap due to the extensive application of galvanized products has led to a significant increase of the zinc content in the electric furnace dust, so how to realize high-value comprehensive utilization of zinc-containing dust has become a key issue for the sustainable development of the iron and steel industry. Based on the principle of recycling zinc resources, this study proposes an innovative full life cycle process for the preparation of electro-galvanized sheet using zinc-containing dust as raw material and deep eutectic solvents (DESs) as medium. Zinc plating was successfully prepared on duplex steel automobile plates using choline chloride-urea DES (Reline) as the electrolyte, and the modifying effects of different concentrations of nicotinic acid (NA) on the electrochemical system of the solution and the prepared plating were also investigated. The results show that the addition of 0.06 M NA to the system can modulate the deposition morphology of the plating layer, leading to the generation of ultrafine grains, and the surface densities and flatness are significantly improved. Besides, the addition of NA to the system increased the hardness value by 67.5 % and reduced the coefficient of friction by 38.8 % compared to the plating obtained in the system without additives; the corrosion rate decreased from 0.374 mm·a-1 to 0.023 mm·a-1, and the corrosion mechanism of the zinc layer was a direct dissolution process of zinc. This study realizes the morphology regulation of electroplated zinc plating, and greatly improves the aesthetics, mechanical properties and corrosion resistance of the plating at the same time, also the preparation process is in line with the requirements of the green development, which can provide a novel solution for the automotive high-quality plating.

Experimental and numerical investigation on failure behavior of hybrid bonded/bolted GFRP single-lap joints under static shear loading

The mechanical performance of the GFRP (Glass Fiber Reinforced Polymer) hybrid bonded/bolted single-lap joints under static shear loading is investigated. Static loading tests considering the hybrid joints with one bolt, four bolts, and nine bolts were first conducted to study the failure mechanism of hybrid joints, where failure process, rigidity, failure load, and failure modes were focused. Finite element (FE) analysis involving the material degradation and failure laws was also carried out for exploring the internal mechanism of joints’ failure. Based on the verified FE model, the effects of plate thickness and bolt edge distance on the failure capacity and strength of the hybrid joints were further investigated by performing a numerical parametric analysis. Results show that, the failure process of the hybrid joints can be divided into two stages which correspond to the failures of adhesive layer and GFRP plates, respectively. The joint rigidity of joints increases by 98.9 %∼133.1 % comparing the second loading stage to the first stage, and it is found that the rigidity in the first stage is hardly affected by the number of fasten bolts, while it decreases with more bolts in the second stage due to the severe incompleteness of GFRP plates. The failure patterns of the hybrid joints mainly include the slippage between connected plates, the compressive failure and shear failure of GFRP material, and the inclination of bolts. A proper arrangement of bolts can lead to shear failure of GFRP which makes full use of the material property. The final failure loads of four-bolt and nine-bolt joints are respectively 14.5 % and 22.9 % higher than the single-bolt specimen. As the plate thickness getting greater, the shear bearing capacity of hybrid joint increases almost linearly, while it would increase first and then descend with increasing bolt edge distance. In general, the achievement of this work can provide references for the design and further study of the GFRP hybrid joints.

TARGETING HYPERTROPHIC CHONDROCYTES IN OSTEOARTHRITIS: THE ROLE OF INFLAMMATION AND THE USE OF A MULTI-MODEL APPROACH IN SEARCH OF PHARMACOLOGICAL TREATMENTS

In osteoarthritis, chondrocytes acquire a hypertrophic phenotype that contributes to matrix degradation. Inflammation is proposed as trigger for the shift to a hypertrophic phenotype. Using in vitro culture of human chondrocytes and cartilage explants we could not find evidence for a role of inflammatory signalling activation. We found, however, that tissue repair macrophages may contribute to the onset of hypertrophy (doi: 10.1177/19476035211021907) Intra-articularly injected triamcinolone acetonide to inhibit inflammation in a murine model of collagenase-induced osteoarthritis, increased synovial macrophage numbers and osteophytosis, confirming the role of macrophages in chondrocyte hypertrophy occurring in osteophyte formation (doi: 10.1111/bph.15780).In search of targets to inhibit chondrocyte hypertrophy, we combined existing microarray data of different cartilage layers of murine growth plate and murine articular cartilage after induction of collagenase-induced osteoarthritis. We identified common differentially expressed genes and selected those known to be associated to inflammation. This revealed EPHA2, a tyrosine kinase receptor, as a new target. Using in silico, in vitro and in vivo models we demonstrated that inhibition of EPHA2 might be a promising treatment for osteoarthritis.Recently, single cell RNA-seq. has revealed detailed information about different populations of chondrocytes in articular cartilage during osteoarthritis. We re-analysed a published scRNA-seq data set of healthy and osteoarthritic cartilage to obtain the differentially expressed genes in the population of hypertrophic chondrocytes compared to the other chondrocytes, applied pathway analyses and then used drug databases to search for upstream inhibitors of these pathways. This drug repurposing approach led to the selection of 6 drugs that were screened and tested using several in vitro models with human chondrocytes and cartilage explants.In this lecture I will present this sequence of studies to highlight different approaches and models that can be used in the quest for a disease modifying drug for osteoarthritis.

Methods for modeling the dissipative characteristics of layered composites

The main methods for modeling dissipative characteristics of layered composites are considered: the principle of elastic-viscoelastic correspondence and energy method. Mathematical models of damped oscillations are given for layered anisotropic plates. A numerical procedure for solving the problem of damped oscillations of a three-layer monoclinic plate containing a two-stage method for solving a complex eigenvalue problem. It is noted that the energy method for modeling energy dissipation at vibrations of layered composite structures is a special case of the method, based on the principle of elasticviscoelastic correspondence. Shown, that in addition to the classical formulation of the energy method, in which the terms energy balance equations are approximately found by their own forms and vibration frequencies of a conservative mechanical system, there is one more an approximate method for calculating the dissipative characteristics of orthotropic composite structures. The advantages of this method are the possibility of using existing commercial software systems (Ansys et al.), which numerically implement the finite element method, and shortcomings - the need to be limited to the use of classical theories of thinwalled structures (Bernoulli-Euler, Kirchhoff-Love) for descriptions of deformation of composite structures. It has been found that the use the classical formulation of the energy method allows with a high accurately predict the values of mechanical loss coefficients up to ηmax = 0.02. Further increase in damping levels construction is accompanied by a decrease in the accuracy of the forecast.

Elliptic tangent imaging method for layered plate interfacial defects based on non-dispersive guided waves

Layered structures play an increasingly pivotal role in diverse fields such as aerospace, pipeline transportation, and petrochemical engineering. However, defects situated at the interfaces between layers pose a challenge for conventional Non-Destructive testing (NDT) methods, impeding accurate imaging. This research introduces the elliptic tangent imaging method based on interface wave modes to visualize interfacial defects within layered structures. The interface wave mode, characterized by high-frequency non-dispersive traits, facilitates precise localization of defects. Its energy concentration in the interface enhances sensitivity to interfacial defects. The elliptic tangent imaging method proposed in this paper capitalizes on the transmission coefficients of the oblique incidence technique for surface waves, enabling the concurrent determination of defect location and orientation using one pair of transducers. The application of the orthogonal matched pursuit algorithm for sparse representation of the raw signal further enhances positioning accuracy. This paper establishes an automatic detection system for interface waves, demonstrating swift transducer switching. Experimental validation of wave velocity aligns closely with theoretical calculations. In experiments focusing on interfacial defect imaging in bilayer aluminum-steel plates, the system exhibits the capability to accurately depict interfacial defects with varying orientations.

Surface modification of epoxy resin by MnO2–H2SO4–H2O–Na4P2O7 for enhanced adhesion to electroless copper

The purpose of this study was to enhance the adhesion strength between the epoxy resin (EP) substrate and the electroless copper plating layer by utilizing a MnO2–H2SO4–H2O–Na4P2O7 system for surface modification. The effect of the volume ratio of VH2SO4:VH2O and the duration of surface modification on various surface characteristics and adhesion strength was examined. The results provide valuable insights into the relationship between these factors and their impact on the properties of the surface. Optimal results were achieved with a volume ratio of VH2SO4:VH2O at 3:1, a surface modification time of 20 min, Na4P2O7 content of 30 g L−1, and a modification temperature of 50 °C. Following the surface modification treatment, the EP substrate surface exhibited many deep micro-holes, significantly improving surface roughness. Due to the enhanced roughness on the surface and the application of suitable modifications, the contact angle on the EP substrate surface exhibited a significant decrease from 94.6° to 19.5°. This alteration caused the surface to transition from hydrophobic to hydrophilic. The adhesion strength between the EP substrate and the electroless copper plating layer was significantly increased to 0.74 kN m−1. This improvement was attributed to the combined effects of surface roughness and hydrophilicity of the substrate surface.

Mathematical models for determining and analyzing thermal regimes in mining industry mechanism structures

Purpose. To develop linear and nonlinear mathematical models of heat conduction for isotropic heterogeneous media with internal heating. This will allow for an increased accuracy in determining temperature fields, which will subsequently impact the effectiveness of designing mechanisms, devices, and individual components of structures that have a layered structure and are subjected to heat stress. Methodology. For the development of linear and nonlinear mathematical models of the temperature field and the analysis of temperature regimes in layered media with internal thermal heating, the coefficient of thermal conductivity is described as a whole using asymmetric unit functions. This makes it possible to solve a differential equation with singular coefficients in both linear and nonlinear boundary value problems of heat conduction with appropriate boundary conditions. Findings. Quadratic equations are obtained to determine the analytical solutions of linear and nonlinear boundary problems of heat conduction for a layered plate with internal heat load. Originality. The scientific novelty lies in the given method of linearization of the nonlinear mathematical model of heat conduction and obtaining analytical solutions, in a closed form, of the corresponding linear and nonlinear boundary value problems for isotropic layered media subjected to internal heating. Practical value. The developed linear and nonlinear mathematical models for determining the temperature distribution in layered structures with internal heating make it possible to analyze heat exchange processes and ensure the thermal stability of such structures. This also makes it possible to increase the heat resistance of structures and protect them from overheating, which can lead to damage to individual components and elements of mechanisms, as well as to the entire structure as a whole. The resulting analytical solutions can be used to predict temperature fields in mine shafts, underground environments and mechanisms of mining equipment, in particular, in drilling and underground compressor stations, ventilation systems and other equipment, which improves work efficiency and reduces useful energy consumption.

Investigation of guided wave propagation in nanoscale layered periodic piezoelectric plates based on Eringen's nonlocal and strain gradient theory

This paper investigates the dynamic propagation behavior of guided waves in nanoscale media composed of alternating layers of piezoelectric phases. The study employs Eringen's nonlocal and strain gradient theories to derive equations for symmetric wave propagation and the scattering relations of guided waves perpendicular to these structures. Dispersion curves are calculated and plotted to compare these theories, considering the influence of nanoscale size-effect, volume ratio of constituent layers, and material length scale. Using the strain gradient theory, the paper explores the impact of length scale parameters on the propagation behavior of horizontally polarized guided waves in an alternating layer structure of nanoscale piezoelectric material, specifically nanoscale piezoelectric laminates. The analysis involves calculating localization factors and dispersion curves to analyze the effects of size-effect and length scale parameters on wave propagation and band structures. Additionally, the study plots and analyzes changes in mechanical displacement and electrical potential, followed by an investigation and discussion of nanoscale size effects and the effects of the material's length scale parameter on dispersion curves and conversion modes within specific regions. The results highlight that the length scale effect parameter significantly impacts the mode conversion zones and band gap structures, more so than the NLPE continuum theory suggests. As the strain gradient parameter increases, these zones shift towards higher wavenumbers and to the right . Furthermore, introducing the length scale factor results in a substantial decrease in both the formation of conversion zones and the density of dispersion curves.

Robust PbO2 modified by co-deposition of ZrO2 nanoparticles for efficient degradation of ceftriaxone sodium.

In recent years, PbO2 electrodes have received widespread attention due to their high oxygen evolution reaction (OER) activity. However, due to the brittle nature of the plating layer, it is easy to cause the active layer to fall off. Pb2+ will leach out with the electrochemical process causing secondary pollution. The starting point of this study is established to improve the stability and adhesion of the electrode coating. Electrochemical oxidation technology has the characteristics of high treatment efficiency, wide range of applications, and non-polluting environment. In this study, conventional PbO2 electrodes were modified by using co-deposition of ZrO2 nanoparticles. In addition, α-PbO2 was added to increase the stability of the electrodes. At a high current density of 1A/cm2, the accelerated life of the pure PbO2 electrode is 648h, the accelerated life of the PbO2-ZrO2 electrode is 1.37 times that of the pure PbO2, and the electrode with an added α-PbO2 layer is 1.69 times that of the pure PbO2 electrode. The amount of dissolved Pb2+ was only 29% of that of pure PbO2. The electrochemical performance of the electrode is evaluated by studying the degradation effect of ceftriaxone sodium (CXM). The addition of ZrO2 nanoparticles alters the particle size and deposition content of PbO2, leading to a unique crystal structure distinct from pure PbO2. Compared to conventional PbO2 electrodes, the PbO2-ZrO2 can remove chemical oxygen demand (COD) and pollutants more efficiently, removing for 59% increased by 38.47%. Therefore, PbO2-ZrO2 is of great value in the field of electrochemical degradation of industrial pollutants.

Preparation and oxidation performance of a low-diffusion (Ni,Pt)Al coating with an in-situ formed α-W based diffusion barrier

A quasi-continuous α-W-based diffusion barrier (DB) forms in-situ between the (Ni,Pt)Al and the inter-diffusion zone by adding a Ni-W plating layer before the coating preparation. The oxidation behavior of the DB-contained coatings is compared with the normal (Ni,Pt)Al coating at 1100 ℃. The results indicate that the (Ni,Pt)Al with DB exhibits lower oxidation rate, slighter inter-diffusion and flatter surface. Additionally, martensite was observed in (Ni,Pt)Al-DB coatings, which contributed to lower surface rumpling for its higher stiffness and better resistance to creep. The mechanism of the DB and its effects on the oxidation performance of the (Ni,Pt)Al coating were discussed.

An adaptive metastructure concept using bistable composite laminates

Concepts involving adaptive and morphing structures offer us the possibility to realise shape transformation with each shape imparting an individual functionality. There is an increased demand in the design of structural components that are suitable for diverse operational conditions rather than limited to a unique one. However, most concepts of shape adaptive structures require a “holding force” or a continuous supply of energy to maintain a targeted 3D shape. As a result, structures that can lead to desired shape transformation with self-locking capabilities are more desirable.In this work, the concept of multistability is employed to demonstrate a novel class of metastructures that can tackle this challenge. The metastructure is constructed with a periodic arrangement of bistable unit cells made of highly anisotropic composite laminates. Each unit cell comprises multi-sectioned rectangular composite plates exhibiting bistable behaviour due to the thermal residual stresses engendered during the cool-down process from curing to room temperature. To analyse the proposed metastructure, a finite element model has been developed at three hierarchical levels: a plate level, a unit cell level, and a lattice level. At the plate level, a corresponding semi-analytical model using the Rayleigh–Ritz method has also been formulated to validate the finite element models. By carefully tuning the size and spacing of the unit cell, a desired response of the metastructure can be achieved. Additionally, by changing the ply layup and the fibre orientation of each layer of constituent composite plates, conflicting requirements, including load-carrying, shape-adaptive and lightweight, at the same time can be addressed simultaneously. From an extensive parametric study, few designs have been selected for its application in a load-carrying morphing structure.

Fatigue life investigation of rubber bearing for heavy trucks: Optimal design by using finite element method with experimental verification

Rubber bearings consisting of multiple layers of rubber and inlaid steel plates play an important role in cushioning and vibration damping on heavy trucks. In this study, the thermo-mechanical coupling approach together with critical plane analysis theory was utilized to predict fatigue nucleation life of rubber bearing. A new criterion for fatigue life estimation of rubber bearings aiming to eliminate the mesh dependence was proposed, that is, the logarithmic average fatigue life of multiple elements in some local areas with low life (accounting for 0.5% of the total rubber elements) was used instead of the shortest life for a single element. The structure of inlaid steel plates was optimized based on the proposed evaluation criterion for longer service life. The simulation results show that the fatigue life of the optimized rubber bearing is increased by 2.2 times compared with that of the original structure, and the experimental results show that the life of the optimized structure is increased by 2.1 times.

Enhanced oxidation resistance and structural stability of CoNiCrAlY - Yttria stabilized zirconia - LaMgAl11O19 dual ceramic coating by AlY planting layer and subsequent vacuum annealing treatment

AlY plating layer and vacuum annealing were designed to enhance the oxidation resistance and structural stability of CoCrNiAlY–yttria stabilized zirconia (YSZ)–LaMgAl11O19 (LaMA) dual ceramic coating. Vacuum annealing induced a prominent recrystallization of LaMA resulting in numerous micro-cracks. During the oxidation test, these micro-cracks acted as the infiltration channels of O2, accelerating the formation of brittle (Ni, Co)Cr2O4 and high stress initiation, and eventually led to serious fracture. However, AlY plating layer experienced a competitive oxidation during the vacuum annealing and thus led to the formation of α-Al2O3. During the oxidation test, these α-Al2O3 offered a strong barrier ability to block the infiltration of O2, leading to an enhanced oxidation resistance and good structural stability.

Soft Kirigami Composites for Form‐Finding of Fully Flexible Deployables

AbstractA new class of thin flexible structures is introduced that morph from flat into prescribed 3D shapes through strain mismatch between layers of a composite plate. To achieve control over the target shape, two different concepts are coupled. First, motivated by biological growth, strain mismatch is applied between the flat composite layers to transform it into a 3D shape. Depending on the amount of the applied strain mismatch, the transformation involves buckling into one of the available finite number of deformation modes. Second, inspired by kirigami, portions of the material are removed from one of the layers according to a specific pattern. This dramatically increases the number of possible 3D shapes and allows us to attain specific topologies. An experimental apparatus that allows precise control of the strain mismatch is devised. An inverse problem is posed, where starting from a given target shape, the physical parameters that make these shapes possible are determined. To show how the concept works, it focuses on circular composite plates and designs a kirigami pattern that yields a hemispherical structure. The analysis combines a theoretical approach with numerical simulations and physical experiments to understand and predict the shape transition from 2D to 3D. The tools developed here can be extended to attain arbitrary 3D shapes. The initially flat shape suggests that conventional additive manufacturing techniques can be used to functionalize the soft kirigami composite to fabricate, for example, deployable 3D structures, smart skins, and soft electromagnetic metasurfaces.

Seismic behavior of a novel slotted steel plate shear wall under monotonic, cyclic, and time history analysis

Steel plate shear walls (SPSWs) are lateral load-resistant systems used as energy dissipation members in new or existing structures due to their stable hysteretic behavior. However, structures equipped with conventional SPSWs may have a higher initial stiffness, which causes them to be subjected to too much force during moderate earthquakes. In the present study, a novel slotted SPSW is developed to minimize the lateral forces of traditional SPSWs. The slotted SPSW consists of horizontal boundary elements (HBEs), vertical boundary elements (VBEs), and two layers of incline-slotted infill plates (ISIPs) connected by high-strength steel bolts. The proposed system's seismic behavior and damaged mode were compared with those of conventional SPSW using monotonic and cyclic analysis. The research results show that the slotted SPSW exhibits stable hysteretic behavior with a significant energy dissipation capacity. Furthermore, the slotted SPSW was applied to a three-story frame structure. Nonlinear time history analysis was conducted under far-field and near-field ground motion records to determine how a slotted SPSW system affects structure response. According to numerical results, the base force of the structure equipped with a slotted SPSW system was minimized to 37.0% and 49.6% under near-field and far-field earthquakes, respectively.

Mechanism study of composite co-deposited Cu/Co-Mo corrosion-resistant coating on 6061 Al alloy

To improve the bonding strength of the 6061 Al alloy with the plating layer and enhance the corrosion resistance, a Cu/Co-Mo corrosion-resistant plating layer was deposited on its surface. Through Scanning Electron Microscope, it is found that Cu/Co-Mo and the substrate can form an obvious three-layer composite structure, and X-ray diffraction detects that the CoMo coating is an alloy with obvious amorphous characteristics, and its phase composition is Co3Mo. After performance testing, the composite coating improved the corrosion resistance and hardness of the substrate and could play a good role in protecting the 6061 Al alloy. In addition, the mechanism of induced codeposition of CoMo alloy was investigated, and the deposition of Mo6+ was determined by cyclic voltammetry to be a three-step six-electron irreversible reduction reaction. Chronopotentiometry revealed that Mo6+ underwent a diffusion-controlled transient nucleation process. The AC impedance indicated that the selection of a suitable voltage is beneficial to reduce the hydrogen precipitation reactions during electrodeposition.

Ehlers-Danlos syndrome in the practice of an otorhinolaryngologist: Clinical observation and literature review

The presented own clinical observation showed that functional dysphonia can be one of the clinical manifestations of EhlersDanlo syndrome: it is the deep layer of the own plate of the vocal fold, containing a large amount of collagen, that is most susceptible to changes in this pathology. The patient of the vocal voice for many years: a picture of hypotonic dysphonia was revealed during video pharyngostroboscopy – gaping of the laryngeal ventricles, non-closure of the vocal folds throughout by 1.5–2 mm. Acoustic analysis of the voice showed a decrease and instability in the amplitude of the pitch frequency, a narrowing of the dynamic range, a decrease in the intensity of the voice in the area of individual tones of the transient register, an increase in the level of noise components in the spectrum. The patient underwent a course of neuromuscular electrophonopedic stimulation No. 12 in combination with taking B vitamins for three weeks; after that, an increase in voice endurance was subjectively noted, however, according to the results of phonetography, spectrography and videolaryngostroboscopy, no visible positive dynamics was noted. The rheumatologist revealed hyperextension and increased traumatism of the skin, increased folding of the palms and flat feet. DNA sequencing revealed mutations in the genes and confirmed the diagnosis of Ehlers-Danlo syndrome.

Tensile-shear properties of steel-Al adhesively bonded dissimilar joints and the effect of Al plate thickness

Lap shear dissimilar joints between aluminium (Al) alloy, A6061-T6, and stainless steel, type 304, were fabricated by adhesive bonding. Three Al plates with different thicknesses were used to investigate the effect of the Al plate thickness on the tensile-shear properties, namely the effect of bending stiffness of Al plates. The maximum tensile-shear loads increased with increasing Al plate thicknesses. The fracture through the adhesive layer (cohesive fracture) occurred when the Al plate was the thickest, while the interface fracture between Al plate and adhesive layer appeared on the fracture surface with decreasing Al plate thickness. Fatigue strengths also increased with increasing Al plate thickness. When the fatigue strengths were normalized by the tensile strengths, the effect of the plate thickness became negligible. FEM analyses revealed that the stress concentration at the edge of adhesive on Al side decreased with increasing Al plate thickness, which could be related to the dependence of tensile and fatigue properties on the Al plate thickness.

A reconfigurable multifunctional polarization converter based on active metasurface

In this paper, we report a reconfigurable multifunctional polarization converter (RMPC) based on positive-intrinsic-negative (PIN) diodes, enabling to achieve different functions in different bands and states. The simulations and experiments show that when the PIN diode is off, it acts as a broadband linear polarization (LP) converter at 9.12–15.93 GHz. Simultaneously, when the PIN diode is on, the LP incident wave is converted into a left-handed circular polarization wave at 8.69–11.41 GHz and a cross-polarization wave at 13.40–14.97 GHz, whereas full reflection is obtained at 12.05–12.54 GHz. The RMPC consists of two dielectric plates and three layers of metal copper plates. Finally, a sample was fabricated and measured, the simulated and experimental results were in good agreement. Compared with other works, the RMPC has more working states and wider operating frequency bands, which has an application potential in the field of radar stealth and satellite communication.