Uniform Distribution Research Articles

Cement slurry penetration behavior of swirl grouting technology

Traditional pressure grouting technology operates under steady pressure conditions, causing the grout to easily flow along preferential pathways. This results in uneven grout penetration and increased economic costs. This study proposes swirl grouting technology, which effectively improves this problem. To verify the effectiveness of swirl grouting, a fan-shaped blade tool was also proposed. The grout penetration performance was investigated through experimental studies. The length, width, height, weight, and uniformity of the grouted bodies produced by the swirl grouting method were compared with those produced by the steady pressure grouting method. Then, the mechanisms of swirl grouting were analyzed through transparent disc visualization experiments. The results demonstrated that, at different water–cement ratios, the swirl device increased the penetration length in the X, Y, and Z directions by 43.3%, 27.8%, and 45.8%, respectively, compared to the conventional straight device, and by 57.3%, 39.4%, and 55.6%, respectively, compared to the fan blade device. Moreover, the swirl device increased the weight of the grouted stone body by 54.9% compared to the conventional straight device and by 91.0% compared to the fan blade device, significantly enhancing filling efficiency. The uniformity coefficient of the swirl device permeation decreased by 56.6% and 51.0%, respectively, compared to the conventional straight device and the fan blade device, resulting in a more uniform grout distribution. The transparent disc visualization experiment further revealed the advantage of the swirl device in promoting the migration of fine particles, with a significant increase in average penetration distance and a penetration shape closer to a regular circle. The rotating flow path of the swirl device imparts additional rotational momentum and multidirectional penetration capabilities. The resulting turbulence accelerates the mixing of grout with the soil matrix, facilitating the migration of fine particles, expanding flow channels, and reducing flow resistance. This combination of effects enhances penetration efficiency and reduces energy loss. This study offers significant practical application value for improving engineering quality, construction efficiency, and reducing costs.

Efficiency study of nickel-containing glass-fiber catalysts for CO2 methanation

The work is dedicated to the synthesis and investigation of Ni-containing catalysts based on glass-fiber carriers (GFC) with an additionally deposited secondary layer of porous SiO2 for the process of carbon dioxide methanation. Ni-based GFCs were prepared using the surface thermosynthesis (STS) and pulse surface thermosynthesis (PSTS) methods, involves heat treatment of the catalyst with the supported Ni precursor at a high heating rate; such procedure was not applied earlier for production of CO2 methanation catalysts. The GFC sample prepared by the PSTS method with a fuel additive in the precursor composition is characterized by a more uniform distribution of Ni particles on the catalyst surface and better dispersion of Ni, smaller crystallite size: NiO crystallites in this freshly prepared GFCs are smaller than 10 nm and Ni crystallites in reduced catalysts are less than 30 nm. As a result, this sample demonstrated the highest apparent activity in the methanation reaction among all synthesized GFCs, it has also showed a significantly higher specific activity per unit mass of nickel compared to the commercial Ni-Al2O3 analogue. The synthesized catalysts are original, they can be effectively applied for development of novel highly efficient technologies for energy conversion/storage systems and greenhouse gas emission control.

Text2Face: Text-Based Face Generation With Geometry and Appearance Control.

Recent years have witnessed the emergence of various techniques proposed for text-based human face generation and manipulation. Such methods, targeting bridging the semantic gap between text and visual contents, provide users with a deft hand to turn ideas into visuals via text interface and enable more diversified multimedia applications. However, due to the flexibility of linguistic expressiveness, the mapping from sentences to desired facial images is clearly many-to-many, causing ambiguities during text-to-face generation. To alleviate these ambiguities, we introduce a local-to-global framework with two graph neural networks (one for geometry and the other for appearance) embedded to model the inter-dependency among facial parts. This is based upon our key observation that the geometry and appearance attributes among different facial components are not mutually independent, i.e., the combinations of part-level facial features are not arbitrary and thus do not conform to a uniform distribution. By learning from the dataset distribution and enabling recommendations given partial descriptions of human faces, these networks are highly suitable for our text-to-face task. Our method is capable of generating high-quality attribute-conditioned facial images from text. Extensive experiments have confirmed the superiority and usability of our method over the prior art.

Investigation of machining performance of waspaloy using copper-graphite composite electrodes in electric discharge machining

Abstract This study endeavoured to investigate the machining of Waspaloy using Electric Discharge Machining (EDM), utilizing copper-graphite composites as the tool material. Given the limited existing research on machining Waspaloy with composite tools, this study aims to address this gap by employing a copper-graphite composite tool. In this work, pure copper electrode and three composite electrodes with varying graphite percentages in copper, viz. copper containing 5%, 10%, and 15% graphite (CuGr-5, CuGr-10, and CuGr-15), are utilized for experimentation. Composite electrodes are fabricated by the stir-casting process. The scanning electron microscope reveals that the graphite specks are homogeneously disseminated over the matrix material. The Taguchi mixed orthogonal array was used for developing experimental runs. By varying the current, polarity, pulse on and off times, tool materials, and gap, machining performance was measured in terms of Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra). It was observed that CuGr-5 provides an enhancement in MRR due to the improved electric conductivity, bridging effect, and increased energy concentration at the spark gap. Diverse characteristics witnessed on the surface morphology include black dots, globules, remelted layers, micro-cracks, and scratches. When machined with a CuGr5 electrode, the surface quality improved owing to the completed flushing and uniform distribution of generated heat as confirmed through worn surface morphology. The parameters were optimized utilizing the PROMETHEE optimization technique; it was found that the CuGr-5 electrode with the assessment value 0.02458 was optimal for machining of Waspaloy.

Optimizing Tool Offset in Static Shoulder Friction Stir Welding of Al6061 to Ti6Al4V for Enhanced Joint Integrity

The precise control of tool offset in static shoulder friction stir welding (SSFSW) is vital for enhancing the mechanical properties and overall effectiveness of dissimilar metal joints. The present study investigates the impact of tool offset on the development of microstructural features, intermetallic compound formation, texture analysis, and mechanical characteristics of SSFSWed Al6061 to Ti6Al4V joints. The results demonstrate that a 2.5 mm tool offset results in an average grain size of 2.65 μm, compared to larger grains of about 4.76 μm and 7.31 μm observed at 2.0 mm and 1.5 mm offsets, respectively. The percentage of low-angle grain boundaries also varies, reaching up to 42.2% at a 2.5 mm offset compared to 48.6% at 2.0 mm and 64.1% at 1.5 mm, indicating enhanced homogeneity in the microstructural properties. Moreover, the ultimate tensile strength at the 2.5 mm tool offset reaches 279 MPa, which is 5.7% higher than at the 2.0 mm offset and 13.4% higher than at the 1.5 mm offset. This improvement is attributed to more uniform distribution of Ti particles over the stir zone. Texture analysis further supports these findings, with the development of alpha fibre at 2.5 mm offset enhancing ductility, thereby underscoring the critical role of tool offset in achieving sound dissimilar metal weldments.

Enhanced properties of hard metal WC-Ni processed from nanostructured powders

In this study, we investigated the effects of nanostructured composite powders (WC-Ni), nickel binder content, and sintering techniques on the morphology and mechanical properties of tungsten carbide. An alternative low-temperature gas-solid reaction route with a short reaction time was employed to produce nanostructured composite powders with 5 and 15 wt% Ni. The powders were consolidated using spark plasma sintering (SPS) and conventional vacuum furnace sintering at temperatures of 1350 °C and 1450 °C. The composite powders were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and particle size measurements. The expansion/contraction of the compacted nanocomposite powders was studied through dilatometric analysis. The composite powders exhibited a uniform distribution of Ni, in both compositions. For the WC-5 wt% Ni nanocomposite powders, the average crystallite sizes for WC and Ni were 41.6 nm and 46.2 nm, respectively. While, for the WC-15 wt% Ni nanocomposite, the crystallite sizes for WC and Ni were 45.6 and 38.4 nm. The sintered composites were evaluated through XRD, SEM, measurements of density and Vickers hardness. The enhanced sinterability of the nanostructured powders enabled their consolidation into (WC-Ni) hard metal with densities approaching the theoretical relative density of 96.07 %, even with low binder content (5 wt% Ni). This is attributed to the uniform distribution of Ni and an extensive Ni-WC interface present prior to sintering. The SPS process at 1350 °C produced sintered bodies (WC-5 wt% Ni and WC-15 wt% Ni) with higher Vickers hardness (2322 HV and 1512 HV, respectively) and superior microstructural quality compared to samples produced by conventional vacuum furnace techniques. These results demonstrated that the mechanical properties of the system WC-Ni processed by SPS are superior to those obtained by vacuum furnace. Therefore, WC-Ni hard metals processed by this approach is a promising alternative to conventional hard metals (WC-Co) for a wide range of applications.

Simultaneously enhanced confinement and suppressed diffusion of lithium polysulfides via solution-processable porous organic cages for lithium–sulfur batteries

The practical application of lithium−sulfur (Li–S) batteries has been hindered by the shuttle effect of lithium polysulfides (LiPSs), owing to the high solubility of LiPSs in ether-based electrolyte. Herein, a kind of composite cathode (CC3@S) based on porous organic cages (CC3) through grinding-mechanochemistry and dissolution-precipitation is developed. CC3 possesses the merits of non-carbon element framework and intrinsic inner cavity with open window. These features enable CC3 to achieve a uniform distribution of S based on the host-guest encapsulation process and to offer a favorable dual-function catalytic effect during the redox reaction processes, which accelerates the conversion kinetics of LiPSs. Then, both theoretical and experimental simulation results confirm that CC3 can simultaneously confine LiPSs and suppress their diffusion. Finally, the as-resulted Li–S cell, coupling with CC3@S electrode, displays a high capacity of 523 mAh/g with a CE of 96.2% after 1000th cycle at 1 C. This work proves that the molecular crystal material can be seen as the promising model to reveal the confinement and diffusion of LiPSs for Li–S batteries.

Multiobjective enterprise development algorithm for optimizing structural design by weight and displacement

This study presents a novel metaheuristic optimization algorithm for complex multiobjective engineering problems. By integrating advanced population and nondominated sorting techniques into the existing single-objective Enterprise Development Algorithm, this new multiobjective approach effectively identifies Pareto-optimal solutions. The algorithm leverages these techniques to explore engineering solutions within multiobjective search spaces. We evaluated its performance using 29 multiobjective mathematical benchmark problems and conducted a comparative analysis against ten established metaheuristic optimization algorithms. The results demonstrate that the algorithm produces highly accurate approximations of Pareto-optimal fronts while maintaining a uniform distribution of solutions. Additionally, the algorithm was applied to real-world engineering challenges, including the optimization of structures such as the 942-bar tower, the 1536-bar double-layer barrel vault, and the 1410-bar double-layer dome truss, with the primary objectives of minimizing structural weight and maximizing nodal deflection. The findings highlight the algorithm's effectiveness in solving practical engineering problems and consistently achieving optimal Pareto fronts.

Binder jetting and melt infiltration for ceramic-metal fuel fabrication

This study explored the feasibility of fabricating a ZrO2-Zr2Cu ceramic-metal (CERMET) fuel through additive manufacturing (AM) followed by melt infiltration. ZrO2 was selected as a surrogate for UO2 owing to its similar properties, and Zr2Cu was selected owing to its low melting point and neutron absorption cross-section to explore the feasibility of forming a uniform distribution of ceramic particles within a metal matrix. The binder jetting (BJ) AM technique was employed to fabricate preforms with precise control over the particle distribution, addressing the challenges associated with particle agglomeration and ensuring preform shape integrity. Subsequently, spontaneous melt infiltration was employed to achieve a dense and homogeneous CERMET structure. This study emphasized the significance of controlling wettability and surface energies for successful melt infiltration, focusing on the interfacial reactions between Zr2Cu and ZrO2. These results indicate that this novel approach can significantly enhance the thermal and irradiation performance of CERMET fuels.

Research progress of gene therapy combined with tissue engineering to promote bone regeneration

Gene therapy has emerged as a highly promising strategy for the clinical treatment of large segmental bone defects and non-union fractures, which is a common clinical need. Meanwhile, many preclinical data have demonstrated that gene and cell therapies combined with optimal scaffold biomaterials could be used to solve these tough issues. Bone tissue engineering, an interdisciplinary field combining cells, biomaterials, and molecules with stimulatory capability, provides promising alternatives to enhance bone regeneration. To deliver and localize growth factors and associated intracellular signaling components into the defect site, gene therapy strategies combined with bioengineering could achieve a uniform distribution and sustained release to ensure mesenchymal stem cell osteogenesis. In this review, we will describe the process and cell molecular changes during normal fracture healing, followed by the advantages and disadvantages of various gene therapy vectors combined with bone tissue engineering. The growth factors and other bioactive peptides in bone regeneration will be particularly discussed. Finally, gene-activated biomaterials for bone regeneration will be illustrated through a description of characteristics and synthetic methods.

Enhanced Antimicrobial Properties of Polymeric Denture Materials Modified with Zein-Coated Inorganic Nanoparticles.

Polymeric denture materials can be susceptible to colonization by oral microorganisms. Zein-coated magnesium oxide nanoparticles (zMgO NPs) demonstrate antimicrobial activity. The aim of this study was to investigate the antimicrobial effect and adherence of different oral microorganisms on hybrid polymeric denture materials incorporated with zMgO NPs. Five types of polymeric denture materials were used. A total of 480 disc-shaped specimens were divided by material type (n=96/grp), then subdivided by zMgO NPs concentration: control with no nanoparticles and other groups with zMgO NPs concentrations of 0.3%, 0.5% and 1% by weight. Characterization of the polymeric denture materials incorporating zMgO NPs was done, and the antimicrobial activity of all groups was tested against four types of microorganisms: 1) Streptococcus mutans, 2) Staphylococcus aureus, 3) Enterococcus faecalis and 4) Candida albicans. The samples underwent an adherence test and an agar diffusion test. Experiments were done in triplicates. The characterization of the hybrid samples revealed variation in the molecular composition, as well as a uniform distribution of the zMgO NPs in the polymeric denture materials. All hybrid polymeric denture materials groups induced a statistically significant antimicrobial activity, while the control groups showed the least antimicrobial activity. The agar diffusion test revealed no release of the zMgO NPs from the hybrid samples, indicating the NPs did not seep out of the matrix. The zMgO NPs were effective in reducing the adherence of the tested microorganisms and enhancing the antimicrobial activity of the polymeric denture materials. This antimicrobial effect with the polymeric dentures could aid in resisting microbial issues such as denture stomatitis.

Fabrication of FeCoNi alloy film via friction-assisted selective area electrodeposition

Nowadays, carbon neutrality target has been receiving a growing attention in academia and industry. In many industry applications, the wear and fatigue damages of bearing components are the frequent failures affecting machine operation. The maintenance and replacement of damaged bearings cause enormous cost in the aspects of consumptions of energy and materials. In this study, a novel technique of friction-assisted electrodeposition (FAED) is firstly demonstrated for surface remanufacturing of worn bearing races. By using the FAED technique, FeCoNi alloys with nanocrystalline were successfully deposited on the selective surface zone. The surface morphology, microstructure feature as well as mechanical properties of the deposited FeCoNi film were quantitatively characterized. The results have indicated that friction load and electrodeposition time have a remarkable effect on the microstructure of the film and its surface finish. The cross-section exhibited a uniform distribution of Fe, Co and Ni. Meanwhile, typical amorphous and polycrystalline features were observed within the deposited film. Additionally, the as-deposited layer shows desired mechanical properties, including hardness, complex modulus and friction coefficient, matching with those of the GCr15 substrate. Scratch test results showed that a good bonding strength between the coating and the bearing steel was achieved. Moreover, the role of friction in the electrodeposition process has been analyzed. This work provides a new route to achieve selective area electrodeposition of alloy films on bearing steel, which can be further developed for metal surface repairing.

Achieving favourable optical and energy storage efficiency with Sr2+ substitution in BaTiO3

This work reports the structure, microstructure, optical properties, and energy efficiency of solid-state synthesized Sr2+ substituted BaTiO3 (Ba0.95Sr0.05TiO3). The prepared sample was characterized by XRD, HRSEM, and Raman spectroscopy. The Rietveld refinement of the XRD gives a tetragonal crystal structure, further confirmed by the Raman spectroscopy. The HRSEM micrograph confirms the densely packed uniform distribution of grains of the sample. From the band gap study, the energy band gap is found to be 3.18eV for the prepared sample. The dielectric over a wide range of frequency(1kHz-1MHz) and temperature (25-500°C) was measured and discussed. The dielectric response with frequency is fitted with Harviliak-Negami equation from which the relaxation time is calculated. The promising dielectric property with energy storage efficiency makes it a good candidate for various applications.

Cross-rolling induced texture randomization and structural evolution for improved plastic isotropy in Al-Mg alloys with high Mg content

Plastic anisotropy is a key factor that affects the formability and performance of Al-Mg alloys. In this study, the effects of Mg content and strain path shifting from unidirectional rolling (UDR) to cross rolling processes (CR) on plastic anisotropy in Al-Mg alloys were investigated. Al-6 and 9Mg alloys were heat-treated and rolled in two different ways: the first was a UDR process, and the other was a CR process at room temperature. The rolled specimens were analyzed by electron backscattered diffraction method and tensile test. High Mg content suppresses the formation of texture that strengthens the plastic anisotropy in both UDR and CR processes. CR significantly reduces the rolling texture area fraction, leading to greater texture randomness compared to UDR. CR promotes the formation of low-angle deformation bands, which low-angle bands appear to have a weaker impact on deformation resistance and may contribute to the reduced anisotropy in CR-processed materials. CR results in a more uniform distribution of stored energy. R-value which represents plastic anisotropy decreases by shifting from UDR to CR, and by increment of Mg content. Overall, this study demonstrates that CR is a promising approach for improving the formability and performance of Al-Mg alloys by effectively controlling plastic anisotropy.

Dual-Modal Near-Infrared Organic Nanoparticles: Integrating Mild Hyperthermia Phototherapy with Fluorescence Imaging.

Our study seeks to develop dual-modal organic-nanoagents for cancer therapy and real-time fluorescence imaging, followed by their pre-clinical evaluation on a murine model. Integrating NIR molecular imaging with nanotechnology, our aim is to improve outcomes for early-stage cutaneous melanoma by offering more effective and less invasive methods. This approach has the potential to enhance both photothermal therapy (PTT) and Sentinel Lymph Node Biopsy (SLNB) procedures for melanoma patients. NIR-797-isothiocyanate was encapsulated in poly(D,L-lactide-co-glycolide) acid (PLGA) nanoparticles (NPs) using a two-step protocol, followed by thorough characterization, including assessing loading efficiency, fluorescence stability, and photothermal conversion. Biocompatibility and cellular uptake were tested in vitro on melanoma cells, while PTT assay, with real-time thermal monitoring, was performed in vivo on tumor-bearing mice under irradiation with an 808 nm laser. Finally, ex vivo fluorescence microscopy, histopathological assay, and TEM imaging were performed. Our PLGA NPs, with a diameter of 270 nm, negative charge, and 60% NIR-797 loading efficiency, demonstrated excellent stability and fluorescence properties, as well as efficient light-to-heat conversion. In vitro studies confirmed their biocompatibility and cellular internalization. In vivo experiments demonstrated their efficacy as photothermal agents, inducing mild hyperthermia with temperatures reaching up to 43.8 °C. Ex vivo microscopy of tumor tissue confirmed persistent NIR fluorescence and uniform distribution of the NPs. Histopathological and TEM assays revealed early apoptosis, immune cell response, ultrastructural damage, and intracellular material debris resulting from combined NP treatment and irradiation. Additionally, TEM analyses of irradiated zone margins showed attenuated cellular damage, highlighting the precision and effectiveness of our targeted treatment approach. Specifically tailored for dual-modal NIR functionality, our NPs offer a novel approach in cancer PTT and real-time fluorescence monitoring, signaling a promising avenue toward clinical translation.

Influence of the edge effect of the solenoid magnetic field on the discharge process of magnetron sputtering in long and narrow chambers

The fourth-generation light source or future particle accelerators have compact vacuum systems, resulting in a small flow conductance of the beam chamber. The development of NEG (Non-Evaporable Getters) films technology with distributed pumping is a good solution. This technology can obtain a pressure distribution with a small pressure gradient and an ultra-high vacuum of 10-8 Pa inside the vacuum chambers. In the magnetron sputtering process for NEG coating, the inhomogeneity of the magnetic field at the edge of the solenoid is a key parameter for affecting the stability of the magnetron sputtering discharge process. The influence mechanism of the edge magnetic field on the plasma discharge process and discharge uniformity was studied to optimize the coating parameters, which is very important. The Particle-In-Cell/Monte Carlo Collision (PIC/MCC) method was employed to simulate plasma discharge in a narrow vacuum chamber under various edge magnetic field conditions. The potential distribution, charged particle density distribution, and particle density distribution on the target were acquired for four sets of discharge parameters, followed by data processing and analysis. The electric field distribution during the discharge process is closely linked to the non-uniformity of the magnetic field at the solenoid's edge. The smaller Br (the radial component of the magnetic field) component of the magnetic field, the more uniform distribution of Ar+ on the target surface, and the smaller the difference along the length of the vacuum chamber. A smaller radial component (Br) of the magnetic field results in a more uniform distribution of Ar+ on the target surface and reduces variations in film thickness along the length of the vacuum chamber. This is attributed to the small distance between the inner wall of the vacuum chamber and the cathode target. The change in the edge magnetic field will result in the rapid migration of electrons to the inner wall of the vacuum chamber and insufficient collision with the discharge gas, making it challenging to sustain the discharge process. Moreover, fluctuations in the edge magnetic field of the solenoid induce gradient drift and curvature drift in charged particles, resulting in rapid electron loss and alterations in the density and potential distribution of charged particles at the ends of the vacuum chamber, ultimately leading to discharge instability. The research results show the importance of the edge magnetic field effect on the magnetron sputtering coating of the slender vacuum chambers, which provides an important reference for the segmented coating process of similar vacuum chambers in future accelerators.

Synergistic Antibacterial Effects of Selenium-Doped Gold Nanosheets with Notable Near Infrared-II Photothermal Conversion Against Multidrug-Resistant Bacteria

Non-metallic nanoparticles are increasingly acknowledged for their broad-spectrum antibacterial properties, which often face limitations due to structural instability and potential biotoxicity. To address these challenges, integrating non-metallic nanoparticles with plasmonic metal nanostructures offers a promising solution. This fusion not only enhances structural stability but also reduces the required dosage. The synergistic coupling of the inherent antibacterial properties of non-metallic nanoparticles with the plasmonic absorption and photothermal conversion capabilities of metal nanostructures significantly amplifies antibacterial efficacy. In this study, we validate this concept by presenting the successful synthesis of selenium-doped gold nanosheets (AuSe NSs) that demonstrate robust absorption in the second near-infrared (NIR-II) window and exhibit efficient photothermal conversion, followed by testing their antibacterial activity. Notably, Au NSs were synthesized with high shape purity, followed by the introduction of SeO2 and ascorbic acid to facilitate Se doping. The resulting products displayed a uniform distribution of both Au and Se elements, while maintaining the NIR-II absorbance characteristic of Au nanosheets unaffected by the Se doping as evidenced by both experimental and FDTD simulation results. Subsequent assessments of the AuSe NSs demonstrated their potent synergistic antibacterial effects against multidrug-resistant bacteria at minimal inhibitory concentrations (MICs), which suggests that lower dosages can be employed and benefit minimizing potential side effects and optimizing treatment efficiency. Our findings indicate a synergistic boost between the photothermal attributes originating from Au's NIR absorption and Se's inherent antibacterial properties—an aspect minimally explored in prior research and offering a novel solution to tackling antibiotic-resistant bacterial strains.

Modifying of surface properties and structural characteristics of low energy argon beam irradiated methylcellulose/TiO2 nanocomposite films

Flexible polymeric nanocomposites MC/TiO2 films, which consisting of titanium dioxide (TiO2) and methyl cellulose (MC) were fabricated in this research for applied in coating devices. The successful manufacturing of MC/TiO2 sheets were verified by FTIR, SEM and XRD methods, which demonstrated a uniform distribution of TiO2 in MC. Additionally, the chemical bonds of MC and TiO2 contribute for the broadening and decreasing of MC in the peaks intensity of XRD and FTIR with increasing TiO2, indicating the successful incorporation of TiO2 in MC. The impacts of argon beam bombardment on MC/TiO2 composites using cold cathode source with fluencies (2.5×1015, 5×1015 and 7.5×1015 ions/cm2 ). The contact angle, work of adhesion and surface free energy of MC/TiO2 were determined as a function of ion irradiation. The water contact angle is decreased from 70.32o to 43.34o by increasing ion fluence from 2.5×1015 ions/cm2 to 7.5×1015 ions/cm2 , while the surface free energy is enhanced from 38.83 mJ/m2 to 64.17 mJ/m2 . The collected data confirmed that the surface wettability of the irradiated MC/TiO2 films were improved to be can usage in coating and printing applications

Microstructure evolution and mechanical property of B4C/Ti65 composites via laser directed energy deposition

Application of laser additive manufacture technique to fabricate the discontinuous reinforced high-temperature titanium matrix composites found its great potential in the complex components of aerospace industry. This work prepared the B4C/Ti65 composites by laser directed energy deposition (LDED) with special attention paid to the relationship between microstructure and mechanical property of composites. The microstructure of B4C/Ti65 composites under different laser power and B4C content were investigated, based on which the tensile strength and ductility evolution and the underlying strengthening mechanism of the B4C/Ti65 composites were discussed. The submicron TiBw were randomly distributed in the composites with additions of 0.1 wt% and 0.2 wt% B4C. The TiBw and TiCp in the composites with addition of 0.3 wt% B4C exhibited a uniform distribution rather than distributed along the prior β grain boundaries at high laser power. There existed the network structure of TiBw and TiCp in the 0.5 wt% B4C/Ti65 composites. TiCp always adhered to TiBw, and both TiBw and TiCp acted as the nucleation sites for equiaxed α grain, which is responsible for the finer α colonies that benefit to strength with higher B4C content. The tensile tests showed that the 0.3 wt% B4C/Ti65 composite shows a good combination of ultimate tensile strength (1201 MPa) and elongation (5.54 %). The grain refinement strengthening played the dominant role in the strength increment of the B4C/Ti65 composites. In addition, the formation of clustered submicron-TiBw and network structure of TiBw and TiCp in the 0.5 wt% B4C/Ti65 composites greatly upgraded the yield strength.

Analysis of effect on temperature field of tire curing process by initial temperatures and condensate discharging

To improve the heat transfer efficiency and temperature distribution uniformity of steam-heating vulcanization processes, a 3D simulation model was established by Solidworks and transient simulation studies were carried out by Fluent 2021 R1. The effects of four initial tire temperatures and five condensate discharging schemes on the heat transfer efficiency and temperature distribution uniformity were investigated. The study finds that: (1) At the end of the stage of filling the capsule with high-temperature and high-pressure steam, the temperature of the lower mold sidewall is 152.08 °C which is significantly higher than that of the lower mold bead with 128.03 °C, the lower mold shoulder with 115.00 °C, and the lower mold crown with 109.57 °C. (2) With the initial tire temperature increasing from 25 °C to 55 °C, the final temperatures at the lower mold crown and the upper mold sidewall are increased by 12.00 °C and 2.27 °C, respectively, indicating that the increase in the initial temperature helps to raise the temperature at difficult vulcanization locations of the tire. (3) It is recommended to carry out condensate discharging when the volume fraction of condensate at the lower mold sidewall is 0.2 %∼0.3 %, which improves the temperature uniformity in the steam-heating vulcanization process.