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Due to coking deposits, catalyst deactivation severely affects the upgrading of triglyceride biomass. Understanding the chemical nature and development of coke species is essential for mitigating the degree of coking and for the regeneration process of the catalysts. In this study, SEM, XRD, FT-IR, Raman and XPS are employed to gain insights into the coking behavior of RSO during the rapid pyrolysis process. The results show that pyrolysis of RSO produces high quality syngas with 98.72 % H 2 and CO. The unstable O-containing functional groups in the cokes continue to be lost, which indirectly promotes the condensation reaction of aromatic hydrocarbons. The hydroxyl group is the main functional group that affects the reactivity of cokes, and it is one of its more active groups. Although the crystal size of the cokes is growing, its degree of graphitization is decreasing with the temperature increases. The size of the aromatic ring system in the cokes gradually increases with increasing temperature. The cross-linking structure in the coke is constantly being destroyed. Resulting in some O-containing functional groups entering the cokes. Based on this work, the coke evolutionary route of rapid pyrolysis of RSO is proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

In the process of direct use and upgrading of rubber seed oil (RSO), coke formation is a severe problem. Therefore, evolution of the cokes structure is a key factor affecting the efficient utilization of RSO. This study investigates the production of coke during RSO pyrolysis. All cokes are analyzed and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy, CHNS/O analysis, and Raman. The results indicate that cokes on the surface of copper slag (SCS-cokes) are coral-like and the surfaces are relatively rough while cokes on the quartz tube wall (QTW-cokes) have a flat structure. According to FT-IR (500–4000 cm−1), QTW-cokes and SCS-cokes contain a variety of O-containing functional groups. Raman spectra indicate a decrease in the total band area with increasing temperature due to the loss of O-containing functional groups at high temperature. The small aromatic ring systems in cokes are transformed into the large aromatic ring systems. In addition, the yields of pyrolysis gas and cokes increase with increasing temperature, while the opposite is true for tar. RSO pyrolysis products also have value for further processing. Therefore, there is great potential for the co-treatment of CS with RSO. [Display omitted] • The yields of pyrolysis gases during the pyrolysis of rubber seed oil are promoted by copper slag. • Different types of cokes are produced by rapid heating of rubber seed oil at high temperature. • The O-containing functional groups in cokes are unstable at high temperature. [ABSTRACT FROM AUTHOR]

• Beam GPR of SBRT(VMAT) plan can be predicted by the plan or radiomics model via ML. • The ensemble model showed a better performance than plan or radiomic model using different criteria. • The new plan complexity features were proposed. The purpose of this study was to accurately predict or classify the beam GPR with an ensemble model by using machine learning for SBRT(VMAT) plans. A total of 128 SBRT VMAT plans with 330 arc beams were retrospectively selected, and 216 radiomics and 34 plan complexity features were calculated for each arc beam. Three models for GPR prediction and classification using support vector machine algorithm were as follows: (1) plan complexity feature–based model (plan model); (2) radiomics feature–based model (radiomics model); and (3) an ensemble model combining the two models (ensemble model). The prediction performance was evaluated by calculating the mean absolute error (MAE), root mean square error (RMSE), and Spearman's correlation coefficient (SC), and the classification performance was measured by calculating the area under the receiver operating characteristic curve (AUC), accuracy, specificity, and sensitivity. The MAE, RMSE and SC at the 2 %/2 mm gamma criterion in the test dataset were 1.4 %, 2.57 %, and 0.563, respectively, for the plan model; 1.42 %, and 2.51 %, and 0.508, respectively, for the radiomics model; and 1.33 %, 2.49 %, and 0.611, respectively, for the ensemble model. The accuracy, specificity, sensitivity, and AUC at the 2 %/2 mm gamma criterion in the test dataset were 0.807, 0.824, 0.681, and 0.854, respectively, for the plan model; 0.860, 0.893, 0.624, and 0.877, respectively, for the radiomics model; and 0.852, 0.871, 0.710, and 0.896, respectively, for the ensemble model. The ensemble model can improve the prediction and classification performance for the GPR of SBRT (VMAT). [ABSTRACT FROM AUTHOR]

This study investigates the fast catalytic pyrolysis of rubber seed oil over a CO 2 -activated biochar catalyst in the temperature range of 600–800 °C, producing high-value products. The effect of activation time on the catalytic performance and the possibility of using the deactivated catalyst as fuel are also examined. The results indicate that extending the activation time can increase the specific surface area and oxygen active sites of biochar catalyst, thereby improving the catalytic performance. At optimum temperature (800 °C), the biochar catalysts increase the syngas yield from 507.90 mL/g to 634.51 mL/g while facilitating the conversion of polycyclic aromatic hydrocarbons to monocyclic aromatic hydrocarbons. Consequently, the yield of monocyclic aromatic hydrocarbons is increased from 3.72 wt% to 55.77 wt%. Out of the monocyclic aromatic hydrocarbons, benzene and its derivatives are important chemicals, with a yield of 46.80 wt%. Besides, microporous channels in biochar catalysts inhibit the generation of coke, reducing the coke yield from 13.57 to 5.59 wt%; the coke deposit on biochar catalyst is pyrolytic coke. The high heating value of the deactivated biochar catalyst reach 28.605 MJ/kg, and it can be used as a solid fuel. Finally, a mechanism for converting polycyclic aromatic hydrocarbons to monocyclic aromatic hydrocarbons during the fast catalytic pyrolysis of the rubber seed oil is proposed. • The rubber seed oil catalytic pyrolysis over biochar catalyst is performed for the first time. • The catalytic pyrolysis of rubber seed oil produces over 55 wt% monocyclic aromatic compounds. • The microporous channels in the activated carbon has a negative effect on the production of coke. • The mechanism of catalytic pyrolysis of rubber seed oil over biochar catalyst is proposed. [ABSTRACT FROM AUTHOR]

MoS 2 /C nanocomposite with a multilayered sandwich structure based on few-layered MoS 2 and carbon layers in an alternating sequence, was successfully synthesized through a one-step synchronized carbonization and sulfuration method. The hybrids were characterized by X-ray diffraction, High-resolution transmission electron microscopy, Atomic force microscope, Raman and X-ray photoelectron spectroscopic methods. The as-obtained MoS 2 /C nanocomposite applied as lithium-ion batteries anode materials, showed a high initial discharge and charge capacities of 1678.5 and 1386.0 mAh g −1 , respectively. High specific reversible capacity is maintained at fast C rates, e.g., 1390, 1223, 1017, 566, and 450 mAh g −1 at 0.1C, 0.6C, 3C, 10C and 20C, respectively. The good performance of the composite is mainly attributed to the unique few layered composite architectures, which can improve ion/electron transportation and prevent aggregation and restacking during the lithiation/delithiation process. [ABSTRACT FROM AUTHOR]

Copper slag has potential economic and environmental benefits and there is a need for further clean utilization. The traditional recovery methods have the disadvantages of high energy consumption and low Fe recovery ratio. A strategy is proposed for the clean and efficient recovery of Fe from copper slag by deep reduction using rubber seed oil as a reductant. The reduction experiments and thermokinetics analysis are conducted to explore the reaction behavior between rubber seed oil and copper slag. The results show that the Fe recovery ratio of the copper slag is 91.85% and the Fe grade is 95.66% under the optimal conditions for roasting reduction. The process of recycling Fe from copper slag produces new secondary waste residue. Secondary waste residue can be used as a partial starting material for the synthesis of glass-ceramics. The reduction reaction mechanism of copper slag is transformed with increasing temperature. Limiting surface reaction (n = 2) is the restrictive step for the direct reduction reaction region and one-dimension diffusion is the restrictive step for the smelting reduction reaction region. The activation energy of the direct reduction reaction region and smelting reduction reaction region are 16.64 kJ/mol and 13.68 kJ/mol, respectively. This research provides an important approach to the clean utilization of copper slag. [Display omitted] • Using rubber seed oil as a reductant to recover iron from copper slag is very effective. • Secondary waste residue can be used as a partial starting material for the synthesis of glass-ceramics. • The reduction reaction of copper slag is identified into five reaction stages. • Limiting surface reaction (n = 2) is the restrictive step in the direct reduction reactions region. • One-dimension diffusion is the restrictive step in the smelting reduction reaction region. [ABSTRACT FROM AUTHOR]

In this paper, the plastic behavior of fully clamped circular sandwich tubes with metal foam core under transverse loading is analytically, experimentally and numerically studied. Considering the strength of the filled foam, the yield criterion of the compressed sandwich tube is proposed. Using the yield criterion, an analytical model for the plastic behavior of the fully clamped circular sandwich tube is proposed, in which the effects of local denting and the interaction of bending and stretching are considered. The bending experiment of clamped circular sandwich tubes is conducted. The load–deflection and energy–deflection relations are obtained by numerical calculation for the sandwich tubes at different loading positions. The analytical results are in good agreement with numerical and experimental results. Finally, the influences of foam strength, tube-wall thickness, loading position and radius of inner tubes on the plastic behavior of sandwich tubes are studied based on the analytical model. • Plastic behavior of circular sandwich tubes with metal foam core under transverse loading is studied. • An analytical model for plastic behavior of clamped circular sandwich tubes considering the effect of local denting is proposed. • Analytical results capture experimental and numerical results reasonably. • The load-carrying capacity of sandwich tubes increases with increase of foam strength and tube-wall thickness. [ABSTRACT FROM AUTHOR]

As the most significant carbon isotope excursion in the past ∼10 Ma, the Late Miocene Carbon Isotope Shift (LMCIS, ∼7.65 to 6.5 Ma) offers a great opportunity to investigate the carbon-climate dynamics in a warmer-than-today world. However, the driving mechanisms of the LMCIS remain controversial. In this study, we used a 7-box biogeochemical model to simulate the long-term sea water δ 13 C and atmospheric CO 2 changes during the late Miocene. Based on quantitative parameterization of two terrestrial processes (C 4 -grasses expansion and enhanced weathering input) during the late Miocene, our results show that the synergy between the two terrestrial processes may ultimately result in the LMCIS via the perturbation of the land-sea carbon fluxes. Moreover, our results reveal that the re-partitioning of alkalinity and nutrients between the land and the ocean may have influenced the long-term atmospheric CO 2 change during the late Miocene. • Late Miocene C 4 -grass expansion can cause a limited decrease of sea water δ 13 C. • Enhanced weathering input in the late Miocene contributed to the δ 13 C shift too. • The synergy of the two terrestrial forcings could be the major driver of the LMCIS. • Late Miocene p CO 2 decline was linked to land-ocean carbon redistribution. [ABSTRACT FROM AUTHOR]

In this paper, the large deflection of the slender circular metal foam-filled tube (FFT) under transverse loading is studied theoretically and numerically. The yield criterion of the circular foam-filled tube is proposed. Using the yield criterion, the analytical solution for the plastic behavior of slender circular metal foam-filled tube under transverse loading is obtained considering the interaction between bending and stretching and foam strength. Large deflection of the circular metal foam-filled tube is numerically calculated. The analytical model captures numerical results. Influences of tube-wall thickness, punch width, foam strength, loading position and the radius of filled foam on the load-carrying capacity and energy absorption (EA) of foam-filled tubes are discussed in detail. The results show the load-carrying capacity and energy absorption of the foam-filled tubes increase with the increase of tube-wall thickness, foam strength, punch width and the radius of filled foam. • Large deflection of the slender circular metal foam-filled tube under transverse loading is studied. • The analytical solution of the plastic behavior of the circular foam-filled tube is obtained considering foam strength. • The analytical model captures the numerical results reasonably. • Load-carrying capacity and energy absorption increase with increase of tube-wall thickness, foam strength and radius of foam. [ABSTRACT FROM AUTHOR]

In this study, a high power-density dual-output piezoelectric transformer is proposed and experimentally investigated. This transformer consists of a lead zirconate titanate (PZT) ceramic plate with a size of 30 mm×5 mm×1 mm. It has a high mechanical quality factor Qm and high electromechanical coupling coefficient keff. The PZT ceramic plate is poled along the width direction. The electrodes of input and output parts are on the top and bottom surfaces of the ceramic plate and separated by narrow gaps. Lead wires are pressed on the electrodes by a proper elastic force. At a temperature rise lower than 20 °C, the piezoelectric transformer has a maximum output power density of 52.7 W/cm3 with an efficiency of 88%. The maximum efficiency of this piezoelectric transformer is 95%. Voltage gains larger than one and smaller than one are obtained in one transformer. By using a parallel combination of the two outputs of the proposed transformer, a higher output power density of 57.3 W/cm3 can be achieved at the temperature rise lower than 20 °C. [Copyright &y& Elsevier]

Abstract Direct alloying is very difficult for immiscible alloy systems owing to the absence of driving force at equilibrium. To realize alloying for immiscible alloy systems, a method, named as irradiation damage alloying (IDA), is developed and used to prepare W/Ag, Mo/Ag and Mo/Cu laminated metal composites (LMCs) in this work. The IDA process mainly includes three steps: firstly, the multi-energy Ag (or Cu) ions were implanted into the surface of the W (or Mo) matrix; secondly, an Ag (or Cu) coating layer was deposited on the damaged W (or Mo) matrix by vacuum evaporation; thirdly, the obtained W/Ag (Mo/Ag or Mo/Cu) laminated bimetallic samples were annealed at 950 °C in hydrogen for 8 h. It is confirmed that diffusion alloying of immiscible metal atoms indeed takes place and metallurgical bonding interfaces have been constructed successfully. Additionally, to reveal the underlying mechanism of IDA, a thermodynamic model is introduced. It is shown that the storage energy caused by irradiation damage in the matrix metal and the surface energy of the coating layer dominate the thermodynamic driving force. Besides, the storage energy has been confirmed to play a decisive role for the microstructure development of the metallurgical bonding interface. Graphical abstract Unlabelled Image Highlights • The newly developed IDA is a feasible way to realize direct alloying for immiscible systems. • W/Ag, Mo/Ag and Mo/Cu metallurgical bonding interfaces have been constructed successfully by means of IDA. • The storage energy caused by irradiation damage and surface energy of coating layer dominate thermodynamic driving force. • The decisive role for the microstructure development is the storage energy caused by irradiation damage. [ABSTRACT FROM AUTHOR]

The lattice defects in graphene-based carbon materials have been proven to play a critical role for improving the hydrogen evolution reaction (HER) behavior of supported metal catalysts. Nevertheless, accurately manipulating the intensity and distribution of defects for the optimal carbon structure still remains a significant challenge. Here, the microstructures of graphene nanospheres (GNs), in the form of defects distribution and graphitization degree, are accurately regulated by annealing. The optimal electrocatalyst (Ru@GNs300) was achieved by annealing at 300 °C, giving an overpotential of 40 mV at a current density of 10 mA cm−2 together with superior durability in the HER performance test in 1 M KOH. Particularly, the Ru@GNs catalyst has been annealed in situ in transmission electron microscope to monitor its structural evolution. The results indicate that the aggregation of Ru nanoparticles have not been observed up to 900 °C, while the graphitization degree of carbon support increased with elevated temperature. It is worth noting that the optimized electrocatalytic activity of Ru@GNs300 originates from the annealing induced defects regulating of GNs. Thus, the structural optimizing of carbon supports by defect engineering provides an efficient approach to improve the catalytic performance for HER. Image 1 [ABSTRACT FROM AUTHOR]

• Plastic behavior of foam-filled negative Poisson's ratio beam is studied by numerical and theoretical methods. • Considering the effect of the metal foam, the yield criterion of the foam-filled negative Poisson's ratio structure is established. • Based on the yield criterion, the analytical model of plastic behavior of the clamped foam-filled negative Poisson's ratio beam under lateral loading is established. • Analytical results are in good agreement with numerical ones. In this paper, the plastic behavior of foam-filled negative Poisson's ratio (NPR) beams is studied by numerical and theoretical methods. The yield criterion of foam-filled NPR structure is established. On this basis, the plastic behavior of the clamped foam-filled NPR beam under lateral loading is developed considering the interaction between axial force and moment. To make sure the correctness of the theoretical model, the finite element simulation of foam-filled NPR beam is conducted, and the consistency of the results of theoretical analysis and numerical calculation is good. Finally, the effects of material and geometrical parameters, loading location and punch width about the load-bearing capability and energy-absorbing capability of the foam-filled NPR beam are considered by the theoretical model. The result shows that with increasing foam strength, the angular size of the structure, wall thickness and punch width, the load-bearing capability and energy-absorbing capability of foam-filled NPR beams also improve. In addition, when the loading location is nearer to the clamped end, the load and energy absorption is higher. [ABSTRACT FROM AUTHOR]

The paper used the analytical and numerical methods to analyze large deflection of multilayer sandwich beams with foam-filled trapezoidal corrugated and foam cores. Considering both the strength of metal foam and corrugated core, we obtained a yield criterion for the multilayer sandwich structure foam-filled trapezoidal corrugated and foam cores. Based on proposed yield criterion, we further presented an analytical solution for large deflection of such multilayer sandwich beam under transverse loading. Well agreement is achieved between analytical and numerical results. What is more, we discussed the effects of foam strength, punch size, face-sheet thickness and middle foam thickness on the plastic behaviors. • Large deflection of multilayer sandwich beams with foam-filled trapezoidal corrugated and foam cores is studied. • The yield criterion for multilayer sandwich structures with foam-filled trapezoidal corrugated and foam cores is obtained. • Analytical solutions are derived for large deflection of multilayer sandwich beams under transverse loading. • Good agreement is achieved between analytical and numerical results. • Foam strength, punch size and face-sheet thickness have significant effects on plastic behavior of sandwich beams. [ABSTRACT FROM AUTHOR]

• Plastic behavior of foam-filled sandwich beams with circular tube core under transverse loading is studied. • Analytical model for the plastic behavior of the foam-filled sandwich beam with circular tube core is developed. • Analytical results are in good agreement with numerical ones. • Load-carrying capacity of sandwich beams increase with increase of foam strength, face-sheet thickness, tube-wall thickness. Under transverse loading, the plastic behaviour of the foam-filled sandwich beam with circular tube core is researched by numerical and analytical ways in this paper. The yield condition of the foam-filled sandwich section with circular tube core is proposed firstly. Based on the yield condition, the analytical model for the plastic behaviour of the foam-filled sandwich beam with circular tube core under transverse loading is developed, in consideration of the interaction of stretching and bending moment and the strength effect. To make ensure the correctness of the analytical model, the finite element analysis is carried out, and the analytical results are in good agreement with numerical ones. On the basis, the influences of structural and material parameters about load-bearing ability and energy-absorbing ability of foam-filled sandwich beams with circular tube core are discussed by analytical solutions. The results show that, with the increase of foam strength, face-sheet thickness, tube-wall thickness and the width of punch, the load-bearing ability and energy-absorbing ability of the foam-filled sandwich beams with circular tube core increase. In addition, when the loading location is close to the clamped end, the load-bearing ability and energy-absorbing ability of the foam-filled sandwich beam with circular tube core increases significantly. [ABSTRACT FROM AUTHOR]

We report a novel in-situ symbiosis method to prepare reduced graphene oxide wrapped Mn 3 O 4 nanoparticles (rGO/Mn 3 O 4) with uniform size about 50 nm as anodes for lithium-ion batteries (LIBs), which can simplify the preparation process and effectively reduce pollution. The rGO/Mn 3 O 4 nanocomposite exhibited a reversible specific capacity of 795.5 mAh g−1 at 100 mA g−1 after 200 cycles (capacity retention: 87.4%), which benefits from the unique structural advantages and the synergistic effect of rGO and Mn 3 O 4. The Mn 3 O 4 nanoparticles encapsulated among the rGO nanosheets exhibited good electrochemical activity, and the multilayer wrinkled rGO sheets provided a stable 3D conduction channel for Li+/e− transport. The rGO/Mn 3 O 4 nanocomposite is a promising anode candidate for advanced LIBs with excellent cycling performance and rate performance. Furthermore, this new preparation method can be extended to green and economical synthesis of advanced graphene/manganese-based nanocomposites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Introduces novel FeNi-based alloys strengthened with multicomponent L1 2 -type precipitates containing Palladium (Pd), significantly boosting strength while preserving ductility. • Achieved an eightfold yield strength increase in FeNi-based alloys with novel Pd-containing precipitates, maintaining over 10 % ductility. • Pd addition to L1 2 precipitates modifies thermodynamic stability, morphology, coherency, and strengthening effects, offering advanced alloy design pathways. • Discovered that Pd incorporation changes precipitate shapes from spherical to acicular, reducing interface mismatch and enhancing material performance. • Demonstrated the dual role of Pd in precipitate nucleation and shear modulus anisotropy elimination, informing new alloy designs. Precipitation strengthening stands as a paramount strategy for enhancing the mechanical properties of FeNi-based alloys. Conventional precipitates used for strengthening typically contain only two major constituent elements selected from Ni, Al, and Ti. However, knowledge about the intrinsic properties and strengthening mechanisms of multicomponent precipitates remains limited. Here, we propose introducing novel multicomponent L1 2 -type precipitates containing palladium (Pd) to strengthen FeNi-based alloys. The strengthened FeNi alloy achieves an eightfold increase in strength compared to the FeNi matrix while maintaining good ductility. Using meticulous micro-characterization and energy-dispersive X-ray spectroscopy (EDS) techniques, in conjunction with first-principles calculations, this study investigated the effects of Pd addition on the thermodynamic stability, morphology, coherency, and strengthening mechanisms of the precipitates. Results indicate that the addition of Pd induces the nucleation of L1 2 -type precipitates, increases their ductility, and eliminates anisotropy in the shear modulus of the precipitates. Excessive Pd content can alter the shape of precipitates from spherical to acicular due to increased interfacial mismatch between the precipitates and the FeNi matrix. These insights shed light on the impact of Pd addition on the intrinsic properties of L1 2 -type precipitates, offering a promising pathway for the design of advanced FeNi-based alloys with optimized mechanical performance. [ABSTRACT FROM AUTHOR]

Axial splitting and curling collapse of square sandwich metal tubes with metal foam core is investigated analytically and experimentally. The square sandwich metal tube split axially and curl outward along prefabricated cracks. Axial compressive tests of square sandwich metal tubes with prefabricated cracks are conducted and deformation modes are observed. An analytical model for axial splitting and curling behavior of square sandwich metal tube considering plastic bending, crack tearing, curling, foam compression, friction is proposed. It is demonstrated the analytical predictions are in good agreement with experimental results. Influences of foam thickness, tube thickness, die angle, prefabricated crack length, and foam strength are of vital importance to axial splitting and curling of square sandwich metal tube. • A theoretical model is proposed to predict splitting and curling of sandwich tubes. • Axial compression experiments are carried out and deformation modes are found. • Analytical solution captures the experimental results reasonably. • Effects of foam thickness, die angle are of importance to splitting and curling. • The specific energy absorption of the sandwich tube is higher than single tube. [ABSTRACT FROM AUTHOR]

• Create Ti 3 C 2 T x MXene coupled CdS nanostructures by radiation-induced reduction. • Derive amorphous TiO 2 -C nanosheet cocatalysts from Ti 3 C 2 T x /CdS by alkaline treatment. • Achieve the highest H 2 generation rate by aTiO 2 -C/CdS composites at 2.5 wt% Ti 3 C 2 T x. • Unravel the mechanisms mediating the growth and photocatalysis of aTiO 2 -C/CdS. • Pave the way to fabricate viable cocatalysts for solar-to-chemical energy conversion. Developing non-noble-metal cocatalysts is essential for the large-scale implementation of solar-driven H 2 production technology, but still remains a great challenge. In this work, Ti 3 C 2 T x MXene coupled CdS nanostructures are fabricated via one-step gamma-ray radiation-induced reduction in ambient conditions. By subsequent alkaline treatment, a novel cocatalyst of carbon supported amorphous TiO 2 nanosheets (denoted as aTiO 2 -C) is derived from Ti 3 C 2 T x /CdS to form aTiO 2 -C/CdS nanocomposites. The prepared aTiO 2 -C/CdS nanocomposites with cyclability achieve a H 2 evolution rate of 1.48 mmol·g−1·h−1 under visible-light illumination, which is 6.4 and 7.0 times greater than that of pristine Ti 3 C 2 T x /CdS and P-CdS, respectively. The oxygen vacancies in aTiO 2 -C cocatalysts are revealed to act as electron trapping sites to facilitate the transfer of photoexcited electrons and boost photoactivity. Further, the electronic interaction between CdS and aTiO 2 -C prevents Cd2+ from leaching and thus enhances photostability. The results of this work may guide the rational design of viable cost-effective cocatalysts in solar-to-chemical energy conversion and beyond. [ABSTRACT FROM AUTHOR]

• Low-velocity impact of sandwich beams with multilayer sandwich beams is analytically and numerically studied. • Analytical solutions for low-velocity impact of multilayer sandwich beams are developed. • Analytical solution captures the numerical results reasonably. • Impact position, foam strength and face-sheet thickness have significant effects on the dynamic response. The paper focuses on the dynamic response of multilayer sandwich beams with foam-filled trapezoidal corrugated and foam cores under low-velocity impact with heavy-mass using analytical and numerical methods. Based on the yield criterion for the multilayer sandwich structure, the circumscribing and inscribing loci of sandwich structure are obtained. Considering the interaction of bending and stretching, the analytical solution and "bound" solution for the dynamic response of multilayer sandwich beams with foam-filled trapezoidal corrugated and foam cores are developed. The numerical calculations are used to verify the analytical solutions, and all lie within the analytical "bound" predications. Then, the influences of impact position, foam strength and face-sheet thickness on the dynamic response of multilayer sandwich beams are discussed in detail by theoretical model. For a given deflection, the impact force decreases with impact position closer to the midspan, the impact force increases with the increase of foam strength and face-sheet thickness. The present analytical model can effectively predict the dynamic response of fully clamped multilayer sandwich beams with foam-filled trapezoidal corrugated and foam cores under low-velocity impact. [ABSTRACT FROM AUTHOR]

A gradient Fe-Si alloy was prepared by solid powder siliconizing and diffusion annealing using Fe-3.0 wt% Si alloy as raw material. Solid powder siliconizing was carried out at 800 °C for 10–20 min, and siliconized samples with Fe 3 Si phase and FeSi phase were obtained. Then, the siliconized sample was subjected to diffusion annealing at 1050 °C for 1–2 h, and the Fe 3 Si phase and FeSi phase were transformed into single α-Fe phase. The magnetic properties of gradient Fe-Si alloys are higher than those of Fe-Si alloys with uniform Si content distribution (even Fe-6.5 wt%Si alloy). When the surface Si content is 12.3 wt% and the core Si content is 5.0 wt%, the iron loss of the gradient Fe-Si alloy at high frequency is reduced by 97.3% compared with Fe-3.0 wt%Si alloy. Moreover, gradient Fe-Si alloys show excellent magnetic induction intensity and mechanical properties after solid powder siliconizing and diffusion annealing process. This work proposes a solid powder siliconizing and diffusion annealing method to prepare high-performance gradient Fe-Si alloys, which is simple, low-cost, and can control the distribution of Si content in the thickness direction, providing a new idea for the realization of large-scale industrial production of high-performance Fe-Si alloys. • High-performance Fe-Si alloy can be obtained by solid powder siliconizing and diffusion annealing. • Phase transformations in the siliconized layer are detected as follows: α-Fe→FeSi＋Fe 3 Si→α-Fe. • Gradient Fe-Si alloy shows low iron loss, excellent magnetic and mechanical properties. [ABSTRACT FROM AUTHOR]

Understanding the effect of water activity on shale is of major importance for the exploration and development of shale gas reservoirs, especially in the drilling and completion processes. Deep brittle shale samples from the lower Silurian Longmaxi Formation located in Southwest China were characterized using X-ray diffraction (XRD), swelling ratio tests, computerized tomography (CT), Field Emission Scanning Electron Microscope (FE-SEM) and uniaxial compressive strength (UCS) tests. Because of the physical characteristics of the samples, the relationship between water activity and swelling ratio could be approximated by the Frenkel–Halsey–Hill (FHH) equation. The relationships between clay minerals, UCS and water activity were investigated. Based on the physical description of the internal structure, the impact of water activity on micro-fractures was also discussed. The results showed that multilayer adsorption was the main contributor to the swelling of the deep brittle shale samples. The swelling ratio of brittle shale samples was described by the water activity of external environment via a logarithmic expression of the FHH equation, with fractal dimensions ranging from 2.71 to 2.75. The mineralogical composition was a controlling factor on water activity, as shown by the positive correlation between water activity and the total content of clay minerals (TCCM), especially the amount of montmorillonite in illite/smectite mixed layer clay. When soaking in a solution with a water activity above the critical water activity, the brittle samples developed micro-fractures because the clay swelled, acting as cementing material in the weakened planes. The environmental water activity was used to evaluate mechanical properties of the hydrated brittle shale. Brittle shale samples with larger water activity had a higher critical water activity. Water activity analysis led to a better understanding of the characteristics of the brittle shale and the performance of the downhole fluid. [ABSTRACT FROM AUTHOR]

• Dynamic response of sandwich plates with GLARE face-sheets under metal foam projectile impact is studied. • Effects of impulse and thickness on dynamic response are studied by single impact experiments. • The ability of resisting multiple impacts and the ultimate failure mode are measured. • The numerical results are in good agreement with experimental ones. Aluminum honeycomb sandwich plate with fiber metal laminate (FML) as panel can combine the advantages of FML face-sheet and honeycomb core, and has advantages of high specific strength / specific stiffness, lightweight and good energy absorption performance. In this paper, the dynamic response of aluminum honeycomb sandwich plates with Glass Laminate Aluminum Reinforced Epoxy (GLARE) face-sheets under metal foam projectile impact is studied. The single foam projectile impact test is conducted to study the dynamic response of honeycomb sandwich plates with GLARE face-sheets. The debonding between metal and composite layers of the front face-sheet, the fiber fracture, buckling, shear and fracture of core are observed. Also, the multiple foam projectile impact test is carried out to study the impact resistance of the sandwich plate. The numerical calculation is conducted, numerical results are compared with experimental ones. Influences of the impulse, face-sheet thickness, fiber laying angle, honeycomb height, wall thickness of core and cell length of honeycomb on impact resistance and energy absorption of sandwich plates are discussed. It is found that the improvement range of the maximum deflection of back face-sheet gradually decreases with the increase of face-sheet thickness. In addition, by increasing the impulse, decreasing the face-sheet thickness and decreasing the core stiffness, the energy absorption of sandwich plates under metal foam projectile impact can be enhanced. These findings can be used to guide the optimal design of FML sandwich structures under metal foam projectile impact. [ABSTRACT FROM AUTHOR]

In this paper, the plastic behavior of a fully clamped sandwich beam with fiber metal laminate (FML) face-sheets and metal foam core under transverse loading is analytically and numerically studied. Based on the modified rigid plastic model, the analytical solution for large deflection of FML sandwich beams under transverse loading is given, in which the local denting deformation is considered. Finite element results are conducted, and analytical solutions capture numerical results reasonably. The influences of material and geometrical parameters on the plastic behavior of FML sandwich beams are considered. The results show that the present analytical model can be used to predict the plastic behavior of fully clamped FML sandwich beams considering the local denting deformation. • Plastic behavior of sandwich beams with fiber metal laminate (FML) face-sheets is studied. • A simplified formula for plastic behavior of FML sandwich beams is obtained considering local denting. • Analytical solutions capture numerical results reasonably. [ABSTRACT FROM AUTHOR]

The low-velocity impact via a heavy mass on clamped square sandwich plates (SSP) composed of metal foam core and fibre-metal laminate (FML) face-sheets is studied by analytical and numerical methods. Low-velocity impact (LVI) is formulated on square FML sandwich plates based on modified rigid-plastic material approximation (RPMA). Numerical simulations are conducted, and then compared with analytical results reasonably. Influences of the material parameters and impact location on the dynamic behaviors are discussed in detail. This work provides an efficient and simply analytical method to predict low-velocity impact for square FML sandwich plates. [ABSTRACT FROM AUTHOR]