Additive manufacturing(AM)has emerged as one of the most utilized processes in manufacturing due to its ability to produce complex geometries with minimal material waste and greater design freedom.Laser-based AM(LAM)t...Additive manufacturing(AM)has emerged as one of the most utilized processes in manufacturing due to its ability to produce complex geometries with minimal material waste and greater design freedom.Laser-based AM(LAM)technologies use high-power lasers to melt metallic materials,which then solidify to form parts.However,it inherently induces self-equilibrating residual stress during fabrication due to thermal loads and plastic deformation.These residual stresses can cause defects such as delamination,cracking,and distortion,as well as premature failure under service conditions,necessitating mitigation.While post-treatment methods can reduce residual stresses,they are often costly and time-consuming.Therefore,tuning the fabrication process parameters presents a more feasible approach.Accordingly,in addition to providing a comprehensive view of residual stress by their classification,formation mechanisms,measurement methods,and common post-treatment,this paper reviews and compares the studies conducted on the effect of key parameters of the LAM process on the resulting residual stresses.This review focuses on proactively adjusting LAM process parameters as a strategic approach to mitigate residual stress formation.It provides a result of the various parameters influencing residual stress outcomes,such as laser power,scanning speed,beam diameter,hatch spacing,and scanning strategies.Finally,the paper identifies existing research gaps and proposes future studies needed to deepen understanding of the relationship between process parameters and residual stress mitigation in LAM.展开更多
Porous ceramic filters are key components in high-temperature metal-melt filtration processes.Mullite ceramics are widely used owing to their good high-temperature resistance,excellent chemical stability,and solid was...Porous ceramic filters are key components in high-temperature metal-melt filtration processes.Mullite ceramics are widely used owing to their good high-temperature resistance,excellent chemical stability,and solid waste green synthesis characteristics.However,traditional manufacturing processes face challenges in pore structure control for mullite ceramics and obtaining desirable mechanical properties,which limits their application.Recently,ceramic 3D-printing technology has emerged as a research hotspot,and its effectiveness for manufacturing complex 3D porous ceramic structures and controlling their mechanical properties has been demonstrated.This paper provides a detailed overview of the precursor system and toughening mechanisms of mullite,3D-printing technology for mullite ceramics,3D porous structure design for filters,and the melt purification mechanisms of these filters.The objective of this study was to use 3D-printing technology to efficiently manufacture mullite ceramic filter elements with customized structures,controllable pore characteristics,and desirable mechanical properties.展开更多
Indirect additive manufacturing(AM)methods have recently attracted attention from researchers thanks to their great potential for cheap,straightforward,and small-scale production of metallic components.Atomic diffusio...Indirect additive manufacturing(AM)methods have recently attracted attention from researchers thanks to their great potential for cheap,straightforward,and small-scale production of metallic components.Atomic diffusion additive manufacturing(ADAM),a variant of indirect AM methods,is a layer-wise indirect AM process recently developed based on fused deposition modeling and metal injection molding.However,there is still limited knowledge of the process conditions and material properties fabricated through this process,where sintering plays a crucial role in the final consolidation of parts.Therefore,this research,for the first time,systematically investigates the impact of various sintering conditions on the shrinkage,relative density,microstructure,and hardness of the 17-4PH ADAM samples.For this reason,as-washed samples were sintered under different time-temperature combinations.The sample density was evaluated using Archimedes,computed tomography,and image analysis methods.The outcomes revealed that sintering variables significantly impacted the density of brown 17-4PH Stainless Steel samples.The results indicated more than 99% relative densities,higher than the value reported by Markforged Inc.(~96%).Based on parallel porosities observed in the computed tomography results,it can be suggested that by modifying the infill pattern during printing,it would be possible to increase the final relative density.The microhardness of the sintered samples in this study was higher than that of the standard sample provided by Markforged Inc.Sintering at 1330℃ for 4 h increased the density of the printed sample without compromising its mechanical properties.According to X-ray diffraction analysis,the standard sample provided by Markforged Inc.and“1330℃—4 h”one had similar stable phases,although copper-rich intermetallics were more abundant in the microstructure of reference samples.This study is expected to facilitate the adoption of indirect metal AM methods by different sectors,thanks to the high achievable relative densities reported here.展开更多
With the rapid development of the new energy automotive industry,the enhancement of lithium battery performance and production efficiency has become critical.This article explores the application of artificial intelli...With the rapid development of the new energy automotive industry,the enhancement of lithium battery performance and production efficiency has become critical.This article explores the application of artificial intelligence technology in the lithium battery module PACK line,analyzing how it optimizes the production process and improves production efficiency,and predicts future development trends.The PACK line is an important link in battery manufacturing,involving complex processes such as cell sorting,welding,assembly and testing.The application of AI technology in image recognition,data analysis and predictive maintenance provides new solutions for the intelligent upgrading of the PACK line.This article describes the process of the PACK line in detail,analyzes the challenges under current technological levels,and reviews the application cases of AI technology in the manufacturing industry.The study aims to provide theoretical and practical guidance for the intelligent development of lithium battery module PACK lines,discussing the integration of AI technology,its actual performance,technical challenges,and solutions.It is expected that AI technology will play a greater role in the PACK line,and future research will focus on improving the adaptability of models,developing efficient algorithms,and further integrating into the production line.展开更多
Additive manufacturing(AM),as an advanced manufacturing technology,enables the production of personalized orthopedic implant devices with complex geometries that closely resemble bone structures.Titanium and its alloy...Additive manufacturing(AM),as an advanced manufacturing technology,enables the production of personalized orthopedic implant devices with complex geometries that closely resemble bone structures.Titanium and its alloys are extensively employed in biomedical fields like orthopedics and dentistry,thanks to the excellent compatibility with the human body and high corrosion resistance due to the existence of a thin protective oxide layer known as TiO_(2) upon exposure to oxygen on the surface.However,in joint inflammation,reactive oxygen species like hydrogen peroxide and radicals can damage the passive film on Ti implants,leading to their deterioration.Although AM technology for metallic implants is still developing,advancements in printing and new alloys are crucial for widespread use.This work aims to investigate the corrosion resistance of in-situ alloyed Ti536(Ti5Al3V6Cu)alloy produced through electron beam powder bed fusion(EB-PBF)under simulated peri-implant inflammatory conditions.The corrosion resistance was evaluated using electrochemical experiments conducted in the presence of 0.1%H_(2)O_(2) in a physiological saline solution(0.9%NaCl)to replicate the conditions that may occur during post-operative inflammation.The findings demonstrate that the micro-environment surrounding the implant during peri-implant inflammation is highly corrosive and can lead to the degradation of the TiO_(2) passive layer.Physiological saline with H_(2)O_(2) significantly increased biomaterial open circuit potential up to 0.36 mV vs.Ag/AgCl compared to physiological saline only.Potentiodynamic polarization(PDP)plots confirm this increase,as well.The PDP and electrochemical impedance spectroscopy(EIS)tests indicated that adding Cu does not impact the corrosion resistance of the Ti536 alloy initially under simulated inflammatory conditions,but prolonged immersion leads to enhanced corrosion resistance for all biomaterials tested,indicating the formation of an oxide layer after the reduction of the solution oxidizing power.These results suggest that modifying custom alloys by adding appropriate elements significantly enhances corrosion resistance,particularly in inflammatory conditions.展开更多
This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollu...This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollutants.Organic-inorganic composite dots are formed on flexible PI electrodes using evaporation-induced self-assembly(EISA)and electrospray methods.The EISA process is induced by a temperature gradient during electrospray,and the heated substrate partially decomposes the organic parts etched by O_(2) plasma,creating mesoporous structures.Differential pulse voltammetry and cyclic voltammetry demonstrate a linear correlation between analyte concentration and the electrochemical response.Computational studies support the spontaneous adsorption of CC and HQ molecules on model WO_(3) surfaces.The proposed sensor shows high sensitivity,a wide linear range,and a low detection limit for both individual and simultaneous determination of CC and HQ.Real sample analysis on river water confirms practical applicability.The WO_(3)-decorated PI electrode presents an efficient and reliable approach for detecting these pollutants,contributing to environmental safety measures.展开更多
The exploration of heterostructures composed of two-dimensional(2D)transition metal dichalcogenide(TMDc)materials has garnered significant research attention due to the distinctive properties of each individual compon...The exploration of heterostructures composed of two-dimensional(2D)transition metal dichalcogenide(TMDc)materials has garnered significant research attention due to the distinctive properties of each individual component and their phase-dependent unique properties.Using the plasma-enhanced chemical vapor deposition(PECVD)method,we analyze the fabrication of heterostructures consisting of two phases of molybdenum disulfide(MoS_(2))in four different cases.The initial hydrogen evolution reaction(HER)polarization curve indicates that the activity of the heterostructure MoS_(2)is consistent with that of the underlying MoS_(2),rather than the surface activity of the upper MoS_(2).This behavior can be attributed to the presence of Schottky barriers,which include contact resistance,which significantly hampers the efficient charge transfer at junctions between the two different phases of MoS_(2)layers and is mediated by van der Waals bonds.Remarkably,the energy barrier at the junction dissipates upon reaching a certain electrochemical potential,indicating surface activation from the top phase of MoS_(2)in the heterostructure.Notably,the 1T/2H MoS_(2)heterostructure demonstrates enhanced electrochemical stability compared to its metastable 1T-MoS_(2).This fundamental understanding paves the way for the creation of phase-controllable heterostructures through an experimentally viable PECVD,offering significant promise for a wide range of applications.展开更多
Mold manufacturing Extended Enterprise （EE） has the following characteristics： distributed in locality, tight cooperation and frequent information exchange. It needs a collaborative, highly efficient, reliable and ...Mold manufacturing Extended Enterprise （EE） has the following characteristics： distributed in locality, tight cooperation and frequent information exchange. It needs a collaborative, highly efficient, reliable and intelligent manufacturing management system. The background of the Collaborative Manufacturing is introduced. A mold Collaborative Manufacturing Execution System （c-MES） is proposed. The feature of Web Service platform is analyzed. The necessity and feasibility of importing the Web Service to mold c-MES are discussed. Based on Web Service, the model of mold c-MES is built. Every module＇ s function is described in detail, including the functions it supplies and the mechanism of information interaction among them. The feasibility of mold c-MES model is validated by a real mold manufacturing case.展开更多
Simulation technique is an efficient approach to realize the planning and scheduling of manufacturing process of products. An appropriate and efficient manufacturing process model is the basis and key of manufacturing...Simulation technique is an efficient approach to realize the planning and scheduling of manufacturing process of products. An appropriate and efficient manufacturing process model is the basis and key of manufacturing process simulation. By analyzing the features of large-sized and complex products, a method of manufacturing process modeling based on activity network is presented and a mapping algorithm of translating BOM/BOP into the manufacturing process model is designed in detail.展开更多
Virtual organization is a new production patter and a principal part in advanced manufacturing systems such as agile manufacturing. Manufacturability evaluation is the necessary condition to form the virtual organizat...Virtual organization is a new production patter and a principal part in advanced manufacturing systems such as agile manufacturing. Manufacturability evaluation is the necessary condition to form the virtual organization. A new manufacturability evaluation approach is described in this paper, which is carried out based on every process feature under the double-layer model of manufacturing resources proposed by authors. The manufacturing resources that build up the virtual organization are selected according to the results of manufacturability evaluation.展开更多
Carbon dioxide(CO_(2))emissions have become an important factor limiting the high-quality development of the Chinese steel industry.To achieve the goal of carbon peak and carbon neutrality,the strategic planning and t...Carbon dioxide(CO_(2))emissions have become an important factor limiting the high-quality development of the Chinese steel industry.To achieve the goal of carbon peak and carbon neutrality,the strategic planning and technological layout of low-carbon development have been carried out by the Chinese steel industry and enterprises.Based on the summary and analysis of the technology roadmap of low-carbon development in the steel industry and an evaluation of the current research progress of low-carbon technologies,the prospects for the low-carbon development of the steel industry in the future were provided.The results indicate that some steel enterprises in China have already released their low-carbon development roadmaps with a focus on achieving carbon neutrality,which will be realized through advancements in system energy efficiency improvement,resource recycling,process optimization and innovation,breakthrough in smelting technology,product iteration and upgrading,and carbon capture,utilization,and storage(CCUS).The technology development of hydrogen metallurgy and CCUS has shown rapid progress.In the future,the Chinese steel industry must continue to prioritize low-carbon technology and promote the utilization of clean energy.The ratio of electric arc furnace steel should be increased gradually,and the development and application of CCUS technology should be promoted,to ensure the achievement of the“carbon peak and carbon neutrality”goal.展开更多
Automated fiber placement(AFP)enables the efficient and precise fabrication of complex-shaped aerospace composite structures with lightweight and high-performance properties.However,due to the excessive compression on...Automated fiber placement(AFP)enables the efficient and precise fabrication of complex-shaped aerospace composite structures with lightweight and high-performance properties.However,due to the excessive compression on the inner edge of the tow placed along the curved trajectory,the resulting defects represented by buckling and wrinkles in spatial tow steering can induce poor manufacturing accuracy and quality degradation of products.In this paper,a theoretical model of tow buckling based on the first-order shear deformation laminate theory,linear elastic adhesion interface and Hertz compaction contact theory is proposed to analyze the formation mechanism of the wrinkles and predict the formation of defects by solving the critical radius of the trajectory,and finite element analysis involving the cohesive zone modeling(CZM)is innovated to simulate the local buckling state of the steered tow in AFP.Additionally,numerical parametric studies and experimental results indicate that mechanical properties and geometric parameters of the prepreg,the curvature of the placement trajectory and critical process parameters have a significant impact on buckling formation,and optimization of process parameters can achieve effective suppression of placement defects.This research proposes a theoretical modeling method for tow buckling,and conducts in-depth research on defect formation and suppression methods based on finite element simulation and placement experiments.展开更多
Multi-pass ultrasonic impact treatment(UIT)was applied to modify the microstructure and improve the mechanical and tribological characteristics at the near-surface region of commercially pure Ti(CP-Ti)specimens produc...Multi-pass ultrasonic impact treatment(UIT)was applied to modify the microstructure and improve the mechanical and tribological characteristics at the near-surface region of commercially pure Ti(CP-Ti)specimens produced by the laser powder bed fusion(L-PBF)method.UIT considerably refined the L-PBF process-related acicular martensites(α′-M)and produced a well-homogenized and dense surface microstructure,where the porosity content of 1-,3-,and 5-pass UITed samples was reduced by 43,60,and 67%,respectively.The UITed samples showed an enhancement in their near-surface mechanical properties up to a depth of about 300μm.The nanoindentation results for the 3-pass UITed sample revealed an increase of about 53,45,and 220%in its nanohardness,H/E_(r),and H_(3)/E_(r)^(2)indices,respectively.The stylus profilometry results showed that performing the UIT removed the L-PBF-related features/defects and offered a smooth surface.The roughness average(R_(a))and the skewness(R_(sk))of the 3-pass UITed sample were found to be lower than those of the L-PBFed sample by 95 and 223%,respectively.Applying the UIT also enhanced the material ratio,where the maximum load-bearing capacity(~100%)in as-L-PBFed(as-built)and 3-pass UITed samples was obtained at 60-and 10-µm depths,respectively.The tribological investigations showed that applying the UIT resulted in a significant reduction of wear rate and average coefficient of friction(COF)of CP-Ti.For instance,under the normal pressures of 0.05 and 0.2 MPa,the wear rate and COF of the 3-pass UITed sample were lower than those of the L-PBFed sample by 65 and 58%,and 20 and 17%,respectively.展开更多
Variable stiffness mechanisms(VSMs)are a class of compliant mechanisms that can adjust their intrinsic stiffness,which promises to be beneficial in applications needed to interact with the environment,such as collabor...Variable stiffness mechanisms(VSMs)are a class of compliant mechanisms that can adjust their intrinsic stiffness,which promises to be beneficial in applications needed to interact with the environment,such as collaborative robots,wearable robots,and polishing robots.This paper presents the design and optimization of a novel linear VSM,called cLVSM,to produce linear motion,conversely to the majority of VSMs designed to perform rotary motion.By changing the effective length of specially designed circular beams,the cLVSM is capable of continuous stiffness regulation from a minimum value to almost rigid.Different from the VSMs which need rotation-to-translation converting mechanisms for stiffness regulation,the stiffness of the proposed design is adjusted by directly rotating the beams without the use of additional mechanisms,which contributes to improving the structural compactness,and reducing the energy loss and error in transmission.Moreover,the beam rotation needed to regulate the stiffness is almost perpendicular to the beam deflection force,which helps to reduce the torque needed for stiffness regulation.The stiffness model of the proposed VSM is developed using the screw theory,and the design parameters are optimized using the genetic algorithm.The effectiveness of the mathematical model and the performance of the design are verified by simulation and experiments.展开更多
As the take-off of China’s macro economy,as well as the rapid development of infrastructure construction,real estate industry,and highway logistics transportation industry,the demand for heavy vehicles is increasing ...As the take-off of China’s macro economy,as well as the rapid development of infrastructure construction,real estate industry,and highway logistics transportation industry,the demand for heavy vehicles is increasing rapidly,the competition is becoming increasingly fierce,and the digital transformation of the production line is imminent.As one of themost important components of heavy vehicles,the transmission front andmiddle case assembly lines have a high degree of automation,which can be used as a pilot for the digital transformation of production.To ensure the visualization of digital twins(DT),consistent control logic,and real-time data interaction,this paper proposes an experimental digital twin modeling method for the transmission front and middle case assembly line.Firstly,theDT-based systemarchitecture is designed,and theDT model is created by constructing the visualization model,logic model,and data model of the assembly line.Then,a simulation experiment is carried out in a virtual space to analyze the existing problems in the current assembly line.Eventually,some improvement strategies are proposed and the effectiveness is verified by a new simulation experiment.展开更多
Bioactive coating of ceramic scaffolds is an effective way to ameliorate osseointegration and attenuate implant-induced inflammatory responses,which should be biocompatible and possess suitable mechani-cal properties ...Bioactive coating of ceramic scaffolds is an effective way to ameliorate osseointegration and attenuate implant-induced inflammatory responses,which should be biocompatible and possess suitable mechani-cal properties to regulate cell adhesion and migration.In this study,a poly(ethylene glycol)diacry-late/tricalcium phosphate(PEGDA/TCP)ceramic scaffold was prepared using SLA-3D printing,and its com-pressive strength was 8.9±1.0 MPa.Chitosan(Chi)and chondroitin sulfate(CS)were assembled on the sur-face of the PEGDA/TCP scaffolds and crosslinked with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-hydroxysuccinimide(EDC/NHS).Scanning electron microscope(SEM),Fourier transform infrared(FTIR),and laser scanning microscope were used to evaluate the surface modification of the PEGDA/TCP scaffolds.Cellu-lar tests showed that polyelectrolyte multilayers(PEMs)promoted cell adhesion and proliferation of osteoblasts relative to unmodified scaffolds.Furthermore,it can be demonstrated that the SLA-3D printed TCP scaffolds could meet the compressive requirements of trabecular bones,and the bioactivity of the bone scaffolds could be effectively improved by combining them with Chi/CS PEM.展开更多
Clinical photothermal therapy for preventing bone tumor recurrence faces two challenges:systemic toxicity risks from intravenous photosensitizer delivery and insufficient control of photothermal specificity.To address...Clinical photothermal therapy for preventing bone tumor recurrence faces two challenges:systemic toxicity risks from intravenous photosensitizer delivery and insufficient control of photothermal specificity.To address these limitations,we developed a stereolithography(SLA)-based additive manufacturing system for fabricating graphene oxide(GO)-reinforced SiOC/Si_(3)N_(4)bioceramic scaffolds that integrate three functional components:a mechanically robust Si_(3)N_(4)matrix,photothermally active SiOC,and osteoinductive GO.Initially,polysiloxane KH570-H was synthesized,functioning as both a SiOC precursor and a photosensitive polymer,and subsequently formulated with 0-0.8 wt%GO/Si_(3)N_(4)to develop SLA-compatible ceramic slurries.To address GO-induced light scattering defects,a GO content-photosensitive parameter predictive model was established,which improved the dimensional accuracy of printed green bodies by 12.5%compared with that of their nonoptimized counterparts.Following sintering posttreatment,0-0.8 wt%GO/SiOC/Si_(3)N_(4)composite ceramics were fabricated,with the 0.2 wt%GO variant sintered at 1300°C demonstrating optimal multifunctional performance.The compressive strength of the gyroid unit TPMS scaffold with a porosity of 60%reached 41.88 MPa.Notably,the 0.2 wt%GO formulation showed superior cell proliferative capacity,as evidenced by fluorescence microscopy observations of confluent cell monolayers with extensive pseudopodial extensions,indicative of active osteogenic interactions.Under 808 nm near-infrared irradiation(1 W/cm^(2)),the scaffold achieved rapid photothermal activation,reaching the therapeutic threshold of 47.8°C within 10 min in a physiomimetic microenvironment.This photothermally functional GO/SiOC/Si_(3)N_(4)scaffold offers a promising dual-functional solution for post-tumor bone regeneration,combining structural adaptability with spatiotemporally controlled therapeutic precision.展开更多
Vehicle emission has been the major source of air pollution in urban areas in the past two decades. This article proposes an artificial neural network model for identifying the taxi gross emitters based on the remote ...Vehicle emission has been the major source of air pollution in urban areas in the past two decades. This article proposes an artificial neural network model for identifying the taxi gross emitters based on the remote sensing data. After carrying out the field test in Guangzhou and analyzing various factors from the emission data, the artificial neural network modeling was proved to be an advisable method of identifying the gross emitters. On the basis of the principal component analysis and the selection of algorithm and architecture, the Back-Propagation neural network model with 8-17-1 architecture was established as the optimal approach for this purpose. It gave a percentage of hits of 93%. Our previous research result and the result from aggression analysis were compared, and they provided respectively the percentage of hits of 81.63% and 75%. This comparison demonstrates the potentiality and validity of the proposed method in the identification of taxi gross emitters.展开更多
Electron beam melting(EBM) process is an additive manufacturing process largely used to produce complex metallic components made of high-performance materials for aerospace and medical applications.Especially,lattice ...Electron beam melting(EBM) process is an additive manufacturing process largely used to produce complex metallic components made of high-performance materials for aerospace and medical applications.Especially,lattice structures made by Ti-6A1-4V have represented a hot topic for the industrial sectors because of having a great potential to combine lower weights and higher performances that can also be tailored by subsequent heat treatments.However,the little knowledge about the mechanical behaviour of the lattice structures is limiting their applications.The present work aims to provide a comprehensive review of the studies on the mechanical behaviour of the lattice structures made of Ti-6A1-4V.The main steps to produce an EBM part were considered as guidelines to review the literature on the lattice performance:(1) design,(2) process and(3) post-heat treatment.Thereafter,the correlation between the geometrical features of the lattice structure and their mechanical behaviour is discussed.In addition,the correlation among the mechanical performance of the lattice structures and the process precision,surface roughness and working temperature are also reviewed.An investigation on the studies about the properties of heat-treated lattice structure is also conducted.展开更多
文摘Additive manufacturing(AM)has emerged as one of the most utilized processes in manufacturing due to its ability to produce complex geometries with minimal material waste and greater design freedom.Laser-based AM(LAM)technologies use high-power lasers to melt metallic materials,which then solidify to form parts.However,it inherently induces self-equilibrating residual stress during fabrication due to thermal loads and plastic deformation.These residual stresses can cause defects such as delamination,cracking,and distortion,as well as premature failure under service conditions,necessitating mitigation.While post-treatment methods can reduce residual stresses,they are often costly and time-consuming.Therefore,tuning the fabrication process parameters presents a more feasible approach.Accordingly,in addition to providing a comprehensive view of residual stress by their classification,formation mechanisms,measurement methods,and common post-treatment,this paper reviews and compares the studies conducted on the effect of key parameters of the LAM process on the resulting residual stresses.This review focuses on proactively adjusting LAM process parameters as a strategic approach to mitigate residual stress formation.It provides a result of the various parameters influencing residual stress outcomes,such as laser power,scanning speed,beam diameter,hatch spacing,and scanning strategies.Finally,the paper identifies existing research gaps and proposes future studies needed to deepen understanding of the relationship between process parameters and residual stress mitigation in LAM.
基金supported by National Key Research and Development Program of China(Grant No.2022YFB4601400).
文摘Porous ceramic filters are key components in high-temperature metal-melt filtration processes.Mullite ceramics are widely used owing to their good high-temperature resistance,excellent chemical stability,and solid waste green synthesis characteristics.However,traditional manufacturing processes face challenges in pore structure control for mullite ceramics and obtaining desirable mechanical properties,which limits their application.Recently,ceramic 3D-printing technology has emerged as a research hotspot,and its effectiveness for manufacturing complex 3D porous ceramic structures and controlling their mechanical properties has been demonstrated.This paper provides a detailed overview of the precursor system and toughening mechanisms of mullite,3D-printing technology for mullite ceramics,3D porous structure design for filters,and the melt purification mechanisms of these filters.The objective of this study was to use 3D-printing technology to efficiently manufacture mullite ceramic filter elements with customized structures,controllable pore characteristics,and desirable mechanical properties.
文摘Indirect additive manufacturing(AM)methods have recently attracted attention from researchers thanks to their great potential for cheap,straightforward,and small-scale production of metallic components.Atomic diffusion additive manufacturing(ADAM),a variant of indirect AM methods,is a layer-wise indirect AM process recently developed based on fused deposition modeling and metal injection molding.However,there is still limited knowledge of the process conditions and material properties fabricated through this process,where sintering plays a crucial role in the final consolidation of parts.Therefore,this research,for the first time,systematically investigates the impact of various sintering conditions on the shrinkage,relative density,microstructure,and hardness of the 17-4PH ADAM samples.For this reason,as-washed samples were sintered under different time-temperature combinations.The sample density was evaluated using Archimedes,computed tomography,and image analysis methods.The outcomes revealed that sintering variables significantly impacted the density of brown 17-4PH Stainless Steel samples.The results indicated more than 99% relative densities,higher than the value reported by Markforged Inc.(~96%).Based on parallel porosities observed in the computed tomography results,it can be suggested that by modifying the infill pattern during printing,it would be possible to increase the final relative density.The microhardness of the sintered samples in this study was higher than that of the standard sample provided by Markforged Inc.Sintering at 1330℃ for 4 h increased the density of the printed sample without compromising its mechanical properties.According to X-ray diffraction analysis,the standard sample provided by Markforged Inc.and“1330℃—4 h”one had similar stable phases,although copper-rich intermetallics were more abundant in the microstructure of reference samples.This study is expected to facilitate the adoption of indirect metal AM methods by different sectors,thanks to the high achievable relative densities reported here.
文摘With the rapid development of the new energy automotive industry,the enhancement of lithium battery performance and production efficiency has become critical.This article explores the application of artificial intelligence technology in the lithium battery module PACK line,analyzing how it optimizes the production process and improves production efficiency,and predicts future development trends.The PACK line is an important link in battery manufacturing,involving complex processes such as cell sorting,welding,assembly and testing.The application of AI technology in image recognition,data analysis and predictive maintenance provides new solutions for the intelligent upgrading of the PACK line.This article describes the process of the PACK line in detail,analyzes the challenges under current technological levels,and reviews the application cases of AI technology in the manufacturing industry.The study aims to provide theoretical and practical guidance for the intelligent development of lithium battery module PACK lines,discussing the integration of AI technology,its actual performance,technical challenges,and solutions.It is expected that AI technology will play a greater role in the PACK line,and future research will focus on improving the adaptability of models,developing efficient algorithms,and further integrating into the production line.
基金Open access funding provided by Politecnico di Torino within the CRUI-CARE Agreement.
文摘Additive manufacturing(AM),as an advanced manufacturing technology,enables the production of personalized orthopedic implant devices with complex geometries that closely resemble bone structures.Titanium and its alloys are extensively employed in biomedical fields like orthopedics and dentistry,thanks to the excellent compatibility with the human body and high corrosion resistance due to the existence of a thin protective oxide layer known as TiO_(2) upon exposure to oxygen on the surface.However,in joint inflammation,reactive oxygen species like hydrogen peroxide and radicals can damage the passive film on Ti implants,leading to their deterioration.Although AM technology for metallic implants is still developing,advancements in printing and new alloys are crucial for widespread use.This work aims to investigate the corrosion resistance of in-situ alloyed Ti536(Ti5Al3V6Cu)alloy produced through electron beam powder bed fusion(EB-PBF)under simulated peri-implant inflammatory conditions.The corrosion resistance was evaluated using electrochemical experiments conducted in the presence of 0.1%H_(2)O_(2) in a physiological saline solution(0.9%NaCl)to replicate the conditions that may occur during post-operative inflammation.The findings demonstrate that the micro-environment surrounding the implant during peri-implant inflammation is highly corrosive and can lead to the degradation of the TiO_(2) passive layer.Physiological saline with H_(2)O_(2) significantly increased biomaterial open circuit potential up to 0.36 mV vs.Ag/AgCl compared to physiological saline only.Potentiodynamic polarization(PDP)plots confirm this increase,as well.The PDP and electrochemical impedance spectroscopy(EIS)tests indicated that adding Cu does not impact the corrosion resistance of the Ti536 alloy initially under simulated inflammatory conditions,but prolonged immersion leads to enhanced corrosion resistance for all biomaterials tested,indicating the formation of an oxide layer after the reduction of the solution oxidizing power.These results suggest that modifying custom alloys by adding appropriate elements significantly enhances corrosion resistance,particularly in inflammatory conditions.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(RS-202300243390 and 2020R1A5A1018052)supported by the Basic Science Research Program through the National Research Foundation of Korea,funded by the Ministry of Education(2022R1A3B1078163)supported by the Technology Innovation Program(Publicprivate joint investment semiconductor R&D program[K-CHIPS])to foster high-quality human resources(RS-2023-00235484)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)(1415187770)。
文摘This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollutants.Organic-inorganic composite dots are formed on flexible PI electrodes using evaporation-induced self-assembly(EISA)and electrospray methods.The EISA process is induced by a temperature gradient during electrospray,and the heated substrate partially decomposes the organic parts etched by O_(2) plasma,creating mesoporous structures.Differential pulse voltammetry and cyclic voltammetry demonstrate a linear correlation between analyte concentration and the electrochemical response.Computational studies support the spontaneous adsorption of CC and HQ molecules on model WO_(3) surfaces.The proposed sensor shows high sensitivity,a wide linear range,and a low detection limit for both individual and simultaneous determination of CC and HQ.Real sample analysis on river water confirms practical applicability.The WO_(3)-decorated PI electrode presents an efficient and reliable approach for detecting these pollutants,contributing to environmental safety measures.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(2022R1A3B1078163 and 2022R1A4A1031182)supported by the KIMM institutional program(NK248E)and NST/KIMM+3 种基金supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program)(20024772),(RS-2023-00264860)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)(1415187508)supported by the US Department of Energy,Office of Science,Office of Basic Energy Sciences,under grant no.DE-FG02-87ER13808by Northwestern University.
文摘The exploration of heterostructures composed of two-dimensional(2D)transition metal dichalcogenide(TMDc)materials has garnered significant research attention due to the distinctive properties of each individual component and their phase-dependent unique properties.Using the plasma-enhanced chemical vapor deposition(PECVD)method,we analyze the fabrication of heterostructures consisting of two phases of molybdenum disulfide(MoS_(2))in four different cases.The initial hydrogen evolution reaction(HER)polarization curve indicates that the activity of the heterostructure MoS_(2)is consistent with that of the underlying MoS_(2),rather than the surface activity of the upper MoS_(2).This behavior can be attributed to the presence of Schottky barriers,which include contact resistance,which significantly hampers the efficient charge transfer at junctions between the two different phases of MoS_(2)layers and is mediated by van der Waals bonds.Remarkably,the energy barrier at the junction dissipates upon reaching a certain electrochemical potential,indicating surface activation from the top phase of MoS_(2)in the heterostructure.Notably,the 1T/2H MoS_(2)heterostructure demonstrates enhanced electrochemical stability compared to its metastable 1T-MoS_(2).This fundamental understanding paves the way for the creation of phase-controllable heterostructures through an experimentally viable PECVD,offering significant promise for a wide range of applications.
文摘Mold manufacturing Extended Enterprise （EE） has the following characteristics： distributed in locality, tight cooperation and frequent information exchange. It needs a collaborative, highly efficient, reliable and intelligent manufacturing management system. The background of the Collaborative Manufacturing is introduced. A mold Collaborative Manufacturing Execution System （c-MES） is proposed. The feature of Web Service platform is analyzed. The necessity and feasibility of importing the Web Service to mold c-MES are discussed. Based on Web Service, the model of mold c-MES is built. Every module＇ s function is described in detail, including the functions it supplies and the mechanism of information interaction among them. The feasibility of mold c-MES model is validated by a real mold manufacturing case.
文摘Simulation technique is an efficient approach to realize the planning and scheduling of manufacturing process of products. An appropriate and efficient manufacturing process model is the basis and key of manufacturing process simulation. By analyzing the features of large-sized and complex products, a method of manufacturing process modeling based on activity network is presented and a mapping algorithm of translating BOM/BOP into the manufacturing process model is designed in detail.
文摘Virtual organization is a new production patter and a principal part in advanced manufacturing systems such as agile manufacturing. Manufacturability evaluation is the necessary condition to form the virtual organization. A new manufacturability evaluation approach is described in this paper, which is carried out based on every process feature under the double-layer model of manufacturing resources proposed by authors. The manufacturing resources that build up the virtual organization are selected according to the results of manufacturability evaluation.
基金This research was funded by the Ministry of Science and Technology of the People’s Republic of China with Grant number 2020YFB1712801 for study on material flow,energy flow,cost flow,information flow,control flow and their coupling mechanism in steel production.
文摘Carbon dioxide(CO_(2))emissions have become an important factor limiting the high-quality development of the Chinese steel industry.To achieve the goal of carbon peak and carbon neutrality,the strategic planning and technological layout of low-carbon development have been carried out by the Chinese steel industry and enterprises.Based on the summary and analysis of the technology roadmap of low-carbon development in the steel industry and an evaluation of the current research progress of low-carbon technologies,the prospects for the low-carbon development of the steel industry in the future were provided.The results indicate that some steel enterprises in China have already released their low-carbon development roadmaps with a focus on achieving carbon neutrality,which will be realized through advancements in system energy efficiency improvement,resource recycling,process optimization and innovation,breakthrough in smelting technology,product iteration and upgrading,and carbon capture,utilization,and storage(CCUS).The technology development of hydrogen metallurgy and CCUS has shown rapid progress.In the future,the Chinese steel industry must continue to prioritize low-carbon technology and promote the utilization of clean energy.The ratio of electric arc furnace steel should be increased gradually,and the development and application of CCUS technology should be promoted,to ensure the achievement of the“carbon peak and carbon neutrality”goal.
基金Supported by National Natural Science Foundation of China(Grant Nos.52205003 and 51575018)Zhejiang Provincial Natural Science Foundation(Grant No.LD22E050011)Ningbo Municipal Key Projects of Science and Technology Innovation 2025 Plan(Grant No.2022Z070).
文摘Automated fiber placement(AFP)enables the efficient and precise fabrication of complex-shaped aerospace composite structures with lightweight and high-performance properties.However,due to the excessive compression on the inner edge of the tow placed along the curved trajectory,the resulting defects represented by buckling and wrinkles in spatial tow steering can induce poor manufacturing accuracy and quality degradation of products.In this paper,a theoretical model of tow buckling based on the first-order shear deformation laminate theory,linear elastic adhesion interface and Hertz compaction contact theory is proposed to analyze the formation mechanism of the wrinkles and predict the formation of defects by solving the critical radius of the trajectory,and finite element analysis involving the cohesive zone modeling(CZM)is innovated to simulate the local buckling state of the steered tow in AFP.Additionally,numerical parametric studies and experimental results indicate that mechanical properties and geometric parameters of the prepreg,the curvature of the placement trajectory and critical process parameters have a significant impact on buckling formation,and optimization of process parameters can achieve effective suppression of placement defects.This research proposes a theoretical modeling method for tow buckling,and conducts in-depth research on defect formation and suppression methods based on finite element simulation and placement experiments.
文摘Multi-pass ultrasonic impact treatment(UIT)was applied to modify the microstructure and improve the mechanical and tribological characteristics at the near-surface region of commercially pure Ti(CP-Ti)specimens produced by the laser powder bed fusion(L-PBF)method.UIT considerably refined the L-PBF process-related acicular martensites(α′-M)and produced a well-homogenized and dense surface microstructure,where the porosity content of 1-,3-,and 5-pass UITed samples was reduced by 43,60,and 67%,respectively.The UITed samples showed an enhancement in their near-surface mechanical properties up to a depth of about 300μm.The nanoindentation results for the 3-pass UITed sample revealed an increase of about 53,45,and 220%in its nanohardness,H/E_(r),and H_(3)/E_(r)^(2)indices,respectively.The stylus profilometry results showed that performing the UIT removed the L-PBF-related features/defects and offered a smooth surface.The roughness average(R_(a))and the skewness(R_(sk))of the 3-pass UITed sample were found to be lower than those of the L-PBFed sample by 95 and 223%,respectively.Applying the UIT also enhanced the material ratio,where the maximum load-bearing capacity(~100%)in as-L-PBFed(as-built)and 3-pass UITed samples was obtained at 60-and 10-µm depths,respectively.The tribological investigations showed that applying the UIT resulted in a significant reduction of wear rate and average coefficient of friction(COF)of CP-Ti.For instance,under the normal pressures of 0.05 and 0.2 MPa,the wear rate and COF of the 3-pass UITed sample were lower than those of the L-PBFed sample by 65 and 58%,and 20 and 17%,respectively.
基金Supported by National Key R&D Program of China(Grant No.2022YFB4701200)Ningbo Municipal Key Projects of Science and Technology Innovation 2025 Plan(Grant No.2022Z070)National Natural Science Foundation of China(Grant No.52205004).
文摘Variable stiffness mechanisms(VSMs)are a class of compliant mechanisms that can adjust their intrinsic stiffness,which promises to be beneficial in applications needed to interact with the environment,such as collaborative robots,wearable robots,and polishing robots.This paper presents the design and optimization of a novel linear VSM,called cLVSM,to produce linear motion,conversely to the majority of VSMs designed to perform rotary motion.By changing the effective length of specially designed circular beams,the cLVSM is capable of continuous stiffness regulation from a minimum value to almost rigid.Different from the VSMs which need rotation-to-translation converting mechanisms for stiffness regulation,the stiffness of the proposed design is adjusted by directly rotating the beams without the use of additional mechanisms,which contributes to improving the structural compactness,and reducing the energy loss and error in transmission.Moreover,the beam rotation needed to regulate the stiffness is almost perpendicular to the beam deflection force,which helps to reduce the torque needed for stiffness regulation.The stiffness model of the proposed VSM is developed using the screw theory,and the design parameters are optimized using the genetic algorithm.The effectiveness of the mathematical model and the performance of the design are verified by simulation and experiments.
基金supported by China National Heavy Duty Truck Group Co.,Ltd.(Grant No.YF03221048P)the Shanghai Municipal Bureau of Market Supervision and Administration(Grant No.2022-35)New Young TeachersResearch Start-Up Foundation of Shanghai Jiao Tong University(Grant No.22X010503668).
文摘As the take-off of China’s macro economy,as well as the rapid development of infrastructure construction,real estate industry,and highway logistics transportation industry,the demand for heavy vehicles is increasing rapidly,the competition is becoming increasingly fierce,and the digital transformation of the production line is imminent.As one of themost important components of heavy vehicles,the transmission front andmiddle case assembly lines have a high degree of automation,which can be used as a pilot for the digital transformation of production.To ensure the visualization of digital twins(DT),consistent control logic,and real-time data interaction,this paper proposes an experimental digital twin modeling method for the transmission front and middle case assembly line.Firstly,theDT-based systemarchitecture is designed,and theDT model is created by constructing the visualization model,logic model,and data model of the assembly line.Then,a simulation experiment is carried out in a virtual space to analyze the existing problems in the current assembly line.Eventually,some improvement strategies are proposed and the effectiveness is verified by a new simulation experiment.
基金supported by National Key Research and Development Project of China(Grant.No.2022YFB4601403)National Natural Science Foundation of China(Grant.No.52175336).
文摘Bioactive coating of ceramic scaffolds is an effective way to ameliorate osseointegration and attenuate implant-induced inflammatory responses,which should be biocompatible and possess suitable mechani-cal properties to regulate cell adhesion and migration.In this study,a poly(ethylene glycol)diacry-late/tricalcium phosphate(PEGDA/TCP)ceramic scaffold was prepared using SLA-3D printing,and its com-pressive strength was 8.9±1.0 MPa.Chitosan(Chi)and chondroitin sulfate(CS)were assembled on the sur-face of the PEGDA/TCP scaffolds and crosslinked with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-hydroxysuccinimide(EDC/NHS).Scanning electron microscope(SEM),Fourier transform infrared(FTIR),and laser scanning microscope were used to evaluate the surface modification of the PEGDA/TCP scaffolds.Cellu-lar tests showed that polyelectrolyte multilayers(PEMs)promoted cell adhesion and proliferation of osteoblasts relative to unmodified scaffolds.Furthermore,it can be demonstrated that the SLA-3D printed TCP scaffolds could meet the compressive requirements of trabecular bones,and the bioactivity of the bone scaffolds could be effectively improved by combining them with Chi/CS PEM.
基金supported by the Major Basic Research Project of the Shandong Natural Science Foundation(No.ZR2023ZD24)the National Key R&D Program of China(No.2022YFB4601400).
文摘Clinical photothermal therapy for preventing bone tumor recurrence faces two challenges:systemic toxicity risks from intravenous photosensitizer delivery and insufficient control of photothermal specificity.To address these limitations,we developed a stereolithography(SLA)-based additive manufacturing system for fabricating graphene oxide(GO)-reinforced SiOC/Si_(3)N_(4)bioceramic scaffolds that integrate three functional components:a mechanically robust Si_(3)N_(4)matrix,photothermally active SiOC,and osteoinductive GO.Initially,polysiloxane KH570-H was synthesized,functioning as both a SiOC precursor and a photosensitive polymer,and subsequently formulated with 0-0.8 wt%GO/Si_(3)N_(4)to develop SLA-compatible ceramic slurries.To address GO-induced light scattering defects,a GO content-photosensitive parameter predictive model was established,which improved the dimensional accuracy of printed green bodies by 12.5%compared with that of their nonoptimized counterparts.Following sintering posttreatment,0-0.8 wt%GO/SiOC/Si_(3)N_(4)composite ceramics were fabricated,with the 0.2 wt%GO variant sintered at 1300°C demonstrating optimal multifunctional performance.The compressive strength of the gyroid unit TPMS scaffold with a porosity of 60%reached 41.88 MPa.Notably,the 0.2 wt%GO formulation showed superior cell proliferative capacity,as evidenced by fluorescence microscopy observations of confluent cell monolayers with extensive pseudopodial extensions,indicative of active osteogenic interactions.Under 808 nm near-infrared irradiation(1 W/cm^(2)),the scaffold achieved rapid photothermal activation,reaching the therapeutic threshold of 47.8°C within 10 min in a physiomimetic microenvironment.This photothermally functional GO/SiOC/Si_(3)N_(4)scaffold offers a promising dual-functional solution for post-tumor bone regeneration,combining structural adaptability with spatiotemporally controlled therapeutic precision.
基金Project supported by the Key Technologies Research and Development Program of Guangdong Province Foundation (No. 2003A3040301).
文摘Vehicle emission has been the major source of air pollution in urban areas in the past two decades. This article proposes an artificial neural network model for identifying the taxi gross emitters based on the remote sensing data. After carrying out the field test in Guangzhou and analyzing various factors from the emission data, the artificial neural network modeling was proved to be an advisable method of identifying the gross emitters. On the basis of the principal component analysis and the selection of algorithm and architecture, the Back-Propagation neural network model with 8-17-1 architecture was established as the optimal approach for this purpose. It gave a percentage of hits of 93%. Our previous research result and the result from aggression analysis were compared, and they provided respectively the percentage of hits of 81.63% and 75%. This comparison demonstrates the potentiality and validity of the proposed method in the identification of taxi gross emitters.
文摘Electron beam melting(EBM) process is an additive manufacturing process largely used to produce complex metallic components made of high-performance materials for aerospace and medical applications.Especially,lattice structures made by Ti-6A1-4V have represented a hot topic for the industrial sectors because of having a great potential to combine lower weights and higher performances that can also be tailored by subsequent heat treatments.However,the little knowledge about the mechanical behaviour of the lattice structures is limiting their applications.The present work aims to provide a comprehensive review of the studies on the mechanical behaviour of the lattice structures made of Ti-6A1-4V.The main steps to produce an EBM part were considered as guidelines to review the literature on the lattice performance:(1) design,(2) process and(3) post-heat treatment.Thereafter,the correlation between the geometrical features of the lattice structure and their mechanical behaviour is discussed.In addition,the correlation among the mechanical performance of the lattice structures and the process precision,surface roughness and working temperature are also reviewed.An investigation on the studies about the properties of heat-treated lattice structure is also conducted.
