Component Layers Research Articles

Identification of defects in the inner layers of composite components based on capacitive sensing.

This paper describes the development and validation of a rapid internal defect detection method for multilayer composite components. Coplanar array capacitive imaging is based on electrical capacitance tomography, in which all electrodes are arranged in a single plane. The coplanar array capacitive sensor system is based on the capacitive edge effect and reconstructs the dielectric distribution in the sensitive area by measuring the capacitance of the sensor. A 4 × 3 array of coplanar electrode sensors is established and used to image the defects in the inner layers of multilayer composite components. Using a 3D model of the sensor and the sensitivity field, the variation pattern of the sensitivity field is analyzed. By placing different objects into the sensitivity area of the system, changes in the dielectric constant can be observed. Multilayer composite components with void defects are placed in the measurement area for defect detection. The dielectric distribution is visualized by reconstruction algorithms from the capacitance data and sensitivity field data. The results show that the imaging system based on a coplanar array capacitive sensor can reproduce the location of defects and realize the nondestructive testing of complex multilayer composite components.

Nickel nanobrush platform for a magnetic field-assisted electrochemical response enhancement

A single-step electrochemical procedure to synthesize a brush-like platform, which composed of a nickel nanowire array attached to a nickel continuous layer acting as a solid base, is described. Room temperature hysteresis properties of this brush-like architecture (nanobrush) and those of the individual components (nanowires and layer) are determined. It is shown that the direction of the nanobrush magnetic easy axis may be tailored, being also possible to control the magnetic system's coercivity and remanence. The electrochemical response and the catalytic activity of a Ni nanobrush towards the redox probes [Fe(CN) 6 ] 4-/3- and ethanol were evaluated in the presence and absence of an applied magnetic field. The external field strongly affects the system's behavior by enhancing the electrode charge-transfer response, even at fields as low as 6 mT. This improvement was further investigated by Electrochemical Impedance Spectroscopy and Electrochemical Capacitance Spectroscopy studies. It is concluded that the enhanced electrochemical charge-transfer process of the Ni nanobrush electrode, with a magnetic field applied along the Ni nanowires axis, arises from a larger electroactive area. • A Ni nanobrush electrode is obtained by a single step electrodeposition route. • Nanobrush architecture consists of Ni NWs perpendicularly attached to a Ni layer. • The whole platform easy axis orientation is controlled by the brush shape and crystalline texture. • Catalytic activity towards redox probes Fe(CN) 6 −4/−3 and ethanol are evaluated. • A small magnetic field drastically reduces the nanobrush impedance.

Spatial Analysis of the Geoecological Adequability Index in Semi-Arid Watersheds, Northeast of Brazil

stract This research aimed to perform a comparative analysis of Geoecological Adequability (GA) in two semi-arid watersheds in Northeastern Brazil based on a classification carried out in a GIS (Geographic Information System) environment using the algebra map tool. The GA calculation reveals the interactions between landscape components through GIS, namely soil, slope, vegetation and land cover. Weights were assigned (1, 2 or 3) to the different cartographic layers of the geoecological components measured using the algebra map tool, through the arithmetic means, to classify the semiarid basins into different adequability levels, as follows: adequate, partially adequate and inadequate to anthropic uses. These procedures verified the predominance of the “adequate” class with a territorial area above 42% in both investigated basins; the “partially adequate” level and the second most comprehensive class comprised values between 30% and 40%; and, while smaller territorial extensions, below 20%, were “inadequate”. Based on these findings, it was possible to measure the most suitable areas for anthropic use in the studied basins and indicate the areas that should be conserved, with emphasis on protection and/or regeneration of the natural vegetation cover. This is important information concerning the planning and environmental management of these semi-arid landscapes in an objective and efficient way

A Recent Trend on Additive Manufacturing Sustainability with Supply Chain Management Concept, Multicriteria Decision Making Techniques

In the past 3 decades, the emerging technology in manufacturing sector other than conventional manufacturing is additive manufacturing (AM). The additive manufacturing principle was completely born from the research gaps of conventional manufacturing concepts such that the elimination of wastage and produce the component layer upon layer. Every new technology obtains the sustainability that may consider in the supply chain management principle of the raw material to finished products and decision-making techniques are to reach the consumer or customer as properly and periodically but these things are addressed challenges in additive manufacturing. This review paper aims to narrate the common research gaps on additive manufacturing, the structure of the supply chain management on AM, MCDM tools/techniques, AM application in different fields, challenges of selection of additive manufacturing, AM processes, and its application. The traditional method of literature review has been used for this review. The outcome of this review has helped the new researcher’s decision making on the AM various problems as easily and the new researchers may give the experimental solution for explored research gaps.

The Eccentric Compression Performance of Spirally Stiffened Thin-Walled Square Concrete-Filled Steel Tubular Laminated Composite Members

To enhance the local buckling resistance of thin-walled steel pipes and enhance their fire and corrosion resistance, a new spirally stiffened thin-walled square concrete-filled steel tubular laminated composite member with transverse ribs is proposed. Through the four forms of combined members for eccentric pressure testing, it was found that: ordinary thin-walled steel pipe concrete drum buckling is more severe; with spiral ribs, the buckling is limited between the stiffening ribs; and the deformation is significantly reduced. By addressing the problem of cooperative work between the inner and outer structural layers of new components, it was found that, after setting constraints such as steel bars, the integrity of the two can be ensured, and the stress performance is significantly improved; compared to ordinary steel pipe concrete, the load-carrying capacity is 17.9% higher, and the deformation capacity is roughly equivalent. Spiral ribs as a new form of spatial restraint, in addition to increasing the local bending stiffness, manifest an overall restraint role in limiting lateral deformation of the steel pipe, whereas the role of vertical stiffness is insignificant. Based on test evidence, the influences of the width to thickness ratio of spiral ribs and pitch were determined, and reasonable structural measures for the members were given. Through the N–M relationship curve, the limit of damage in compression and tension under eccentricity was obtained at an eccentricity of about 0.9. Finally, a method for calculating the eccentric compressive ultimate load capacity of this new composite member was proposed.

Strong yet ductile nanolamellar high-entropy alloys by additive manufacturing.

Additive manufacturing produces net-shaped components layer by layer for engineering applications1-7. The additive manufacture of metal alloys by laser powder bed fusion (L-PBF) involves large temperature gradients and rapid cooling2,6, which enables microstructural refinement at the nanoscale to achieve high strength. However, high-strength nanostructured alloys produced by laser additive manufacturing often have limited ductility3. Here we use L-PBF to print dual-phase nanolamellar high-entropy alloys (HEAs) of AlCoCrFeNi2.1 that exhibit a combination of a high yield strength of about 1.3 gigapascals and a large uniform elongation of about 14 percent, which surpasses those of other state-of-the-art additively manufactured metal alloys. The high yield strength stems from the strong strengthening effects of the dual-phase structures that consist of alternating face-centred cubic and body-centred cubic nanolamellae; the body-centred cubic nanolamellae exhibit higher strengths and higher hardening rates than the face-centred cubic nanolamellae. The large tensile ductility arises owing to the high work-hardening capability of the as-printed hierarchical microstructures in the form of dual-phase nanolamellae embedded in microscale eutectic colonies, which have nearly random orientations to promote isotropic mechanical properties. The mechanistic insights into the deformation behaviour of additively manufactured HEAs have broad implications for the development of hierarchical, dual- and multi-phase, nanostructured alloys with exceptional mechanical properties.

Flexible and High-Precision Integration of Inserts by Combining Subtractive and Non-Planar Additive Manufacturing of Polymers

Additive manufacturing of polymers offers great potential for the production of complex structures. In particular, Fused Filament Fabrication (FFF) processes can be used to create functionally integrated components, in addition to easy handling, tool-free production and large material options. By combining a FFF system with a robot, inserts of different types can be integrated automatically during the printing process [1]. The low dimensional accuracy of FFF induces great difficulties during the insertion operation. Furthermore, with FFF, a planar layer structure leads to a stair-step effect when overprinting inserts with curved outer contours and reduces the adhesion to the insert. Further, the adhesion of FFF-filaments to the insert depends on the surface treatment of the insert [1]. A FFF system was combined with a robot [2] and has now been expanded to include a subtractive finishing unit and an inline process control based on a machine vision system, which enables the dimensional accuracy of the FFF components to be checked during the printing process. To be able to produce functionally integrated components, a flexible control architecture is being developed that enables the execution of additive and subtractive process steps. Optimal integration of inserts with complex geometries is facilitated by using non-planar layers in the FFF path planning. For this purpose, the filament layers of the FFF components follow the tilted or curved contours of the inserts. The modified process is demonstrated by manufacturing an integrated stator for an electric motor. A system for an additive-subtractive process for the integration of functional inserts was developed. In addition, a concept for the implementation of an improved connection of the inserts through non-planar FFF layers was created. First steps for the integration of the various system-modules and optical analysis of the dimensional accuracy and the development of a printing strategy for non-planar overprinting of the inserts have been realized.

Comparison of stacking sequence on the low‐velocity impact failure mechanisms and energy dissipation characteristics of CFRP/Al hybrid laminates

AbstractCompared with the resin‐based composite laminates, fiber metal laminates (FMLs) have superior impact resistance. In this study, investigations were made to reveal the effects of stacking sequence on the low‐velocity failure mechanisms and energy dissipation characteristics of carbon fiber reinforced plastics (CFRP)/Al hybrid laminates with same areal density. Experiments were carried out to characterize the typical mechanical responses. Failure morphologies were evaluated by X‐ray computed tomography scanning techniques. Then numerical simulations based on three‐dimensional progressive damage analysis were applied to reveal the dynamic evolution process and energy dissipation characteristics. Results indicated that plastic deformation of aluminum layers acted as the dominant factor in energy dissipation. Stacking aluminum layers on the exterior surface could increase the absorbed impact energy and reduce the fracture behavior of the component layers. The specimens with more CFRP layers stacked on the surface exhibited more severe fracture behavior of component layers and larger delamination areas, thus promoting the energy dissipated by CFRP cracking and delamination. This work intended to provide practical guidance for the structural design of fiber reinforced polymer/metal hybrid protective structures.

A New Reliability Allocation Method Based on PSA and AHP for Fusion Reactors

Reasonable and feasible reliability index allocation is significant for improving safety and reducing costs for fusion reactors. Although the reliability index is allocated when designing some key systems, reliability allocation is not implemented from the overall layer to the system and component layers for fusion reactors. In this contribution, fusion reactors are divided into different layers by applying the Analytic Hierarchy Process (AHP); these layers include the overall layer, system layer and component layer, failure mode layer, etc. Combining the Probabilistic Safety Assessment (PSA) model for fusion reactors and AHP, the reliability index is allocated from the overall layer to the system and component layer. Firstly, a new reliability index allocation method based on PSA and AHP for fusion reactors is proposed. Secondly, the PSA model for an in-vessel LOCA accident of fusion reactors is selected as a case study to demonstrate the applications of the proposed method. Lastly, the relationship between PSA, items safety classification and reliability allocation are discussed. The allocation results indicate that the proposed method provides a more systematic reliability allocation scheme and contributes to improving the safety and economy of fusion reactors.

Effect of x on the Electrochemical Performance of Two-Layered Cathode Materials xLi2MnO3–(1−x)LiNi0.5Mn0.5O2

In our study, the cathodic material xLi2MnO3–(1−x)LiNi0.5Mn0.5O2 was synthesized by means of the co-precipitation technique. The effect of x (proportion of components Li2MnO3 and LiNi0.5Mn0.5O2) on the structural, morphological, and electrochemical performance of the material was evaluated. Materials were structurally characterized using X-ray diffraction (XRD), and the morphological analysis was performed using the scanning electron microscopy (SEM) technique, while charge–discharge curves and differential capacity and impedance spectroscopy (EIS) were used to study the electrochemical behavior. The results confirm the formation of the structures with two phases corresponding to the rhombohedral space group R3m and the monoclinic space group C2/m, which was associated to the components of the layered material. Very dense agglomerations of particles between 10 and 20 µm were also observed. In addition, the increase in the proportion of the LiNi0.5Mn0.5O2 component affected the initial irreversible capacity and the Li2MnO3 layer’s activation and cycling performance, suggesting an optimal chemical ratio of the material’s component layers to ensure high energy density and long-term durability.

The effect of front edge on efficiency for point and volume source geometries in p-type HPGe detectors

Monte Carlo (MC) simulations are increasingly being used as an alternative or supplement to the gamma spectrometric method in determining the full energy peak efficiency (FEPE) necessary for radionuclide identification and quantification. The MC method is more advantageous than the experimental method in terms of both cost and time. Experimental calibration with standard sources is difficult, especially for specimens with unusually shaped geometries. However, with MC, efficiency values can be obtained by modeling the geometry as desired without using any calibration source. Modeling the detector with the correct parameters is critical in the MC method. These parameters given to the user by the manufacturer are especially the dimensions of the crystal and its front edge, the thickness of the dead layer, dimensions, and materials of the detector components. This study aimed to investigate the effect of the front edge geometry of the detector crystal on efficiency, so the effect of rounded and sharp modeled front edges on the FEPE was investigated for <300 keV with three different HPGe detectors in point and volume source geometries using PHITS MC code. All results showed that the crystal should be modeled as a rounded edge, especially for gamma-ray energies below 100 keV.

Structural Evaluation by FWD In Flexible Pavement

Pavement performance evaluation an prediction are of great importance to facilitate pavement management system. Pavement evaluations are conducted to determine functional and structural conditions of a pavement section either for purposes of routine monitoring or planned corrective action. The Falling Weight Deflectometer is a device that is used to evaluate pavement and pavement layer stiffness. It is a trailer-mounted device that operates by dropping a weight on to the pavement and measuring the resulting pavement deflections. Various computations may be performed on the deflection data to evaluate the pavement and the stiffness of it and its constituent layers. During testing, a FWD subjects the pavement surface to a load pulse which simulates the load produced by a rolling vehicle wheel. The load pulse is produced by dropping a large weight onto a "buffer" which shapes the pulse, and then transmitted to the pavement through a circular load plate. Data are acquired from various sensors for use in post-test analysis of pavement properties. Data collected from FWD can be used for determination of structural capacity of in-service pavements for analytical analysis of pavement performance, predicting layer moduli for pavement component layers, remaining life of pavements and in deciding strengthening and rehabilitation measures to be adopted for meeting the requirements. Analyses of data are being carried out using standard software as supplied by the manufacturer. Information such as load, layer types and thicknesses, range of moduli and Poisson’s ratio etc. for different layer materials would also be needed for FWD deflection data analysis. While carrying out analyses of data, it assumes material to be homogeneous, isotropic, linear elastic, weightless and semi-infinite. This report contains evaluation on flexible pavement by FWD and according to resulting data, design of overlay will be done accordingly.

Tribological behaviour of a multilayer CrN/DLC coating obtained using PVD-MS

Diamond-like Carbon (DLC) coatings are used as protective layers for steel components due to their hardness, chemical inertia and interesting tribological properties. Reducing wear and friction coefficient is of great importance for industries today in order to increase energy efficiency and reduce harmful emissions to the environment. In this paper, a multilayer CrN/DLC coating is analysed. It was deposited using a commercial Plasma Enhanced Magnetron Sputtering over nitrided and not nitrided mild-alloy steel AISI 4140, produced for the first time in Argentina, at the firm Coating.Tech by Flubetech-Tantal. The base of the coating is an anchor layer made of CrN and the top layer is a chromium-dopped hydrogenated amorphous carbon (a-C:H:Cr), which provides excellent tribological properties. Wear tests were carried out in a Pin-on-Disk apparatus, using an Al2O3 ball as counterpart, with Hertzian contact stress from 1370 up to 1460 MPa. The friction coefficient was μ ∼ 0.1, which is 80% less than the untreated steel and the wear volume loss was reduced several times. The adhesion was evaluated by means of Scratch Test, where major improvement was noticed in the samples which were nitrided as pre-treatment, increasing critical load from 25 N up to 65 N.

Three-Dimensional Smooth Particle Hydrodynamics Modeling and Experimental Analysis of the Ballistic Performance of Steel-Based FML Targets.

In this paper, shields made of 1.3964 stainless steel bonded to a fiber laminate were subjected to ballistic impact response of 7.62 × 51 mm ŁPS (light projectile with a lead core) projectiles. Additionally, between the steel sheet metal and the laminate, a liquid-filled bag was placed, which was a mixture of ethylene glycol (C2H6O2) with 5 wt.% SiO2 nanopowder. Numerical modeling of the projectile penetrating the samples was carried out using the finite element method in the Abaqus program. The elasto-plastic behavior of the projectile material and the component layers of the shields was taken into account. Projectile penetration through glycol-filled bag has been performed using the smooth particle hydrodynamics technique. The morphology of the penetration channel was also analyzed using a scanning electron microscope. For the shield variant with a glycol-filled bag between the steel and laminate plates, the inlet speed of projectile was 834 m/s on average, and 366 m/s behind the sample. For the variant where there was no glycol-filled bag between the steel and laminate plates, the inlet and outlet average velocities were 836 m/s, after 481 m/s, respectively. Referring to the steel-glycol-laminate and steel-laminate variants, it can be concluded that the laminate-glycol-laminate is more effective.

Gradient Multilayer Design of Ti3C2Tx MXene Nanocomposite for Strong and Broadband Microwave Absorption

High‐performance electromagnetic (EM) absorbing materials are in urgent need due to severe EM pollution caused by fast development of communication technology and electronic devices. Gradient structure benefits EM absorbing performance. However, the relevant study is very limited, and the relationship between component layers and overall performance is unclear. Herein, a gradient structure containing impedance matching layer, lossy layer, and reflective layer is built via repeated casting‐drying method using Ti3C2Tx MXene and polyvinyl alcohol. With optimized gradient structure, the minimum reflection loss (RL) reaches −74.8 dB with effective absorbing bandwidth (EAB) covering the whole X‐band. The good absorbing performance is ascribed to the good impedance matching, which is derived from the stepwisely increased permittivity of each layer. Moreover, it is found that RL reaches the lowest value when lossy layer permittivity is close to the average permittivity of impedance matching layer and reflective layer. In addition, the decrease of lossy layer permittivity causes the decrease of total thickness of the gradient structure. This work demonstrates the effectiveness of gradient structure toward strong and broadband microwave absorption and provides rules for designing proper gradient structures to satisfy different requirements.

Pulsed laser deposition and structural evolution of BaF2 nanolayers in Eu-doped BaF2/Al2O3 layered optical nanocomposite thin films

We have developed a pulsed laser deposition (PLD) geometry for the growth of uniform BaF2 nanoscale thin films, through control of the deposition conditions. Our goal is to use the BaF2 layers with controllable structure as component layers in layered optical nanocomposites. The structure of the BaF2 nanolayer evolves as a function of the layer thickness: BaF2 grows via a layer-by-layer growth mode on Al2O3; the layers are amorphous for a thickness < 3 nm, and then become nanocrystalline as the layer thickness increases. The BaF2 nanocrystals have an FCC crystal structure with a weak <111> texture that becomes stronger for thicker films. We then demonstrate that our BaF2 films can be introduced into layered Al2O3/BaF2/EuOx nanocomposite films, which allows for control of the relative position of the Eu ions and the BaF2 layer. Cross-section samples of the multilayered films show interfacial intermixing between the layers, which is related to implantation during the PLD process. This intermixing enables the incorporation of Eu ions into BaF2 layers and form a thin Eu-doped BaF2 nanolayer at the interface. The layered nanocomposite films show photoluminescence (PL) emission from Eu3+ ions, and the PL intensity changes can be correlated with the crystallinity and crystal size changes in the BaF2 layer. Our results provide guidance for achieving thin film nanocomposite materials with controllable structure and photoluminescence behavior for light emitting diodes, photovoltaics and other optical applications.

Research on the Crane Safety Assessment Method Based on the Cloud Model and ICWGT

In crane safety assessment, both quantitative and qualitative indicators are inevitably influenced by the subjective influence of the evaluator, which is unfavorable to the objective requirements of safety assessment. In response to these problems, this study proposes a crane safety assessment method based on the cloud model and the improved combination weighting method of game theory (ICWGT). This evaluation method constructs a multi-level assessment index system for crane safety status by selecting suitable indicators in layers and groups, according to the crane safety assessment rules, and gives a method for constructing the cloud model of the commentary set, the selection and derivation of the membership function, and the determination of the fuzzy relationship matrix. When performing fuzzy synthetic calculations based on the cloud model, the synthetic operator enhances the effect of expectation on entropy and makes the cloud image significantly deformed; this method uses a fine-tuned synthetic operator to improve the algorithm. Compared with the traditional crane fuzzy synthesis assessment method, this method combines the cloud model and ICWGT to achieve finding a balance between expert experience and sample data information, calculating the combined optimization weights of each index and component layer by layer. In order to verify the effectiveness of the method, we take the metal structure system of the shipyard portal crane as an example to explore the applicability of the method in crane safety assessment. The results show that the assessment method can accurately reflect the safety level of the crane and can provide reference material for crane safety assessment.

Analyzing how BERT performs entity matching

State-of-the-art Entity Matching (EM) approaches rely on transformer architectures, such as BERT , for generating highly contex-tualized embeddings of terms. The embeddings are then used to predict whether pairs of entity descriptions refer to the same real-world entity. BERT-based EM models demonstrated to be effective, but act as black-boxes for the users, who have limited insight into the motivations behind their decisions. In this paper, we perform a multi-facet analysis of the components of pre-trained and fine-tuned BERT architectures applied to an EM task. The main findings resulting from our extensive experimental evaluation are (1) the fine-tuning process applied to the EM task mainly modifies the last layers of the BERT components, but in a different way on tokens belonging to descriptions of matching / non-matching entities; (2) the special structure of the EM datasets, where records are pairs of entity descriptions is recognized by BERT; (3) the pair-wise semantic similarity of tokens is not a key knowledge exploited by BERT-based EM models.

Entropy analysis of radiative [MgZn6Zr-Cu/EO] Casson hybrid nanoliquid with variant thermal conductivity along a stretching surface: Implementing Keller box method

Heat transfer is critical due to its broad application in a variety of industries. New hybrid nanofluids are being used to improve the heat transfer competencies of ordinary fluids and have an enormous exponent heat than nanofluids. Hybrid nanofluids, a novel form of nanofluid, are being utilized to improve the heat transfer capacities of regular fluids and have a more outstanding heat exponent than nanofluids. Two-element nanoparticles submerged in a base fluid make up the hybrid nanofluids. Flow and heat transport properties of a hybrid nanofluid across a slick surface are studied in this study. Nanoparticle shape analysis, porous media, thermal conductance variations, and thermal radiative effects are all part of the process. A numerical approach called the Keller box method is used to solve the governing equations numerically. EO-Engine Oil has been used as a rich, viscous base fluid in this study, and a Cason hybrid nanofluid was examined. This fluid contains two diverse forms of nanoparticles: Copper (Cu) and Magnesium Zinc Zirconium alloy (MgZn6Zr). Compared to standard Cu-EO nanofluids, the heat transmission level of such a fluid (MgZn6Zr-Cu/EO) has steadily increased, which is an important finding from this study. The boundary-lamina-shaped layer's components have the highest thermal conductivity, while sphere-shaped nanoparticles have the lowest. When nanoparticles are assimilated, the entropy of the system increases by a factor of three: their ratio by fractional size, their radiative properties, and their thermal conductivity variations.

Digital holographic system for layer-by-layer control of additively manufactured component quality

Subject of study. A digital holographic system for layer-by-layer control of component quality in additive manufacturing able to determine the size and depth of defects on the surface of each layer was investigated. Method. The digital holographic system for layer-by-layer control of component quality in additive manufacturing operates based on a two-wavelength holographic interferometry method. The digital holographic system is based on a Michelson interferometer. The considered method involves recording holograms of the surface of each component layer at two adjacent wavelengths. As a result of hologram reconstruction, the complex amplitudes of the object wave in the reconstruction plane are determined, which, in turn, define the phases of the waves and their difference. The wave phase difference allows the depth of the defect on the component layer surface to be determined. A tunable diode laser and camera based on a CCD matrix are used as the radiation source and detector, respectively. Main results. The results of the investigation of the surfaces of additively manufactured components using the two-wavelength holographic interferometry method are presented. The recognition of large irregularities is possible through expansion of the phase pattern. The detection of surface defects with the size of 25 µm is demonstrated. The reconstructed surface of a component manufactured by laser sintering of successive layers using the M250 additive setup for selective laser sintering and the reconstructed surface of a millimeter-scale macroscopic object are presented. Practical significance. The possible use of the digital holographic system for component quality control in industrial settings, including those applying additive technologies, is demonstrated. The component quality criterion is the absence of defects (cavities or protrusions) with size larger than 25 µm.