Fabrication Method Research Articles

Numerical and experimental study on reinforced 3DCP walls filled with light-weight concrete

This paper explores the structural viability of 3DCP as a novel additive manufacturing method in the construction industry, focusing on its integration and standardization challenges due to its emerging nature. With the construction industry's increasing interest in innovative materials and robotic construction, 3DCP's unique characteristics necessitate thorough investigation to understand its potential fully. This study aimed to assess the structural capacity of 3DCP walls, employing flexural tests on samples filled with lightweight concrete containing EPS, and comparing the outcomes with those of traditionally cast concrete. Through a comprehensive approach that combines experimental work with numerical analysis, this study intended to calibrate the material's properties based on small-scale tests to inform the design of larger structures. Macro and micro-scale numerical modeling methods were investigated for the analysis of 3DCP. The findings revealed that the inherent strength of 3DCP significantly depends on the material's composition and quality. Moreover, it was observed that the structural integrity of 3DCP walls was somewhat inferior to that of fully cast counterparts. However, a strong correlation between the numerical simulations and experimental data underscores the value of this research. By calibrating 3DCP's properties from small-scale experiments, the study provides a foundational basis for designing larger structures with enhanced reliability. Both numerical methods demonstrate high accuracy for the analysis of 3DCP and can be adopted for the analysis of larger structures.

Realization of an Optimized Cylindrical Uniform Magnetic Field Coil via the Flexible Printed Circuit Technology

Abstract The design and fabrication method of magnetic field coils with high uniformity is essential for atomic magnetometers. In this paper, a novel design strategy for cylindrical uniform coils is first proposed, which combines the target-field method (TFM) with an optimized slime mold algorithm (SMA) to determine optimal structure parameters. Then, the realization method for the designed cylindrical coil by using the flexible printed circuit (FPC) technology is presented. Compared with traditional fabrication methods, this method has advantages in excellent flexibility and bending property, making the coils easier to be arranged in limited space. Moreover, the manufacturing process of the FPC technology via a specific cylindrical uniform magnetic field coil is discussed in detail, and the successfully realized coil is well tested in a verification system. By comparing the uniformity performance of the experimental coil with the simulation one, the effectiveness of the FPC technology in producing cylindrical coils has been well validated.

Preparation Method and Benefit Analysis for Unburned Brick Using Construction Solid Waste from Residue Soil

Highly efficient resource utilization of construction solid waste has significant environmental and socioeconomic benefits. In this study, a fabrication method and process optimization of unburned brick from construction residue soil were investigated based on experiments. The effects of cementing the material content, the raw material treatment process, the brick moisture content, and the molding method on the compressive strength of unburned brick were studied and discussed. The experimental results show that 5–20% of ordinary cement can produce a strength grade of 5 MPa–20 MPa for unburned brick, and the utilization rate of the residue soil is greater than 80%. In the case of well-dispersed residual particles, complete drying and rolling are not necessary, and soil particle size within 5 mm is beneficial for obtaining proper sand grading and low mud content, which will improve the strength of unburned brick. The pressure for the press forming of unburned brick should be 10 MPa, and the optimal moisture content of the residue-soil mixture is about 13%. The proposed residue-soil unburned brick has remarkable environmental and economic benefits with low carbon emissions, low cost, and high profit. The methods proposed and optimized in this study can provide important technical support for realizing the large-scale production of residue-soil unburned brick.

Engrossing structural developments of double perovskites for viable energy applications

Investigation for novel functional catalysts illustrates an essential direction in advancing and researching renewable energy. On account of their specific compositional and structural tunability and remarkable stability, double perovskites have been extensively examined as a category of versatile compounds for applications in photocatalysis and electrocatalysis, highlighting them as a promising candidate for catalytic performance and stability. In this review article, we have elaborated on the tunability of double perovskites in terms of their compositions and structures, which proved to be tremendous features for double perovskites in diverse applications. Furthermore, the fabrication methods and the performance optimization comprising band gap tuning of double perovskites have been discussed. The current status of double perovskites for photocatalytic and electrocatalytic H2 production and CO2 reduction, with recent reports, has also been reviewed. Lastly, the challenges and future outlook are put forward.

Fabrication of Surface-Enhanced Raman Scattering (SERS) Substrates in Analytical Science by Natural-inspired Materials: A Review

Surface-Enhanced Raman Scattering (SERS) spectroscopy, as a novel rapid detection technology, offers molecular fingerprinting capabilities that achieve trace-level detection. The key to optimizing SERS sensitivity and reliability lies in the precise control of the nanostructures of SERS substrates. Nature, through billions of years of evolution, has served as a masterful creator, developing organisms with remarkable abilities based on micro/nanostructures, such as the superhydrophobicity of lotus leaves and the strong adhesive forces of gecko feet. This review categorizes the recent developments in SERS substrates inspired by natural materials into three main types: plant-based, animal-based, and virus-based. Each category is explored in detail, describing how their unique nanoarchitectures inspire the development of highly sensitive SERS substrates, along with their fabrication methods and applications in analytical science. Additionally, the review identifies current challenges, such as the uniformity and scalability of naturally inspired SERS substrates and suggests future directions, including the integration of hybrid biomimetic structures and advanced manufacturing techniques. By fostering a deeper understanding of these nature-inspired materials, we aim to enhance the practical application of SERS in analytical science in the future.

Effect of Electrode Distance and Size on Electrocorticographic Recordings in Human Sensorimotor Cortex.

Subdural electrocorticography (ECoG) is a valuable technique for neuroscientific research and for emerging neurotechnological clinical applications. As ECoG grids accommodate increasing numbers of electrodes and higher densities with new manufacturing methods, the question arises at what point the benefit of higher density ECoG is outweighed by spatial oversampling. To clarify the optimal spacing between ECoG electrodes, in the current study we evaluate how ECoG grid density relates to the amount of non-shared neurophysiological information between electrode pairs, focusing on the sensorimotor cortex. We simultaneously recorded high-density (HD, 3mm pitch) and ultra-high-density (UHD, 0.9mm pitch) ECoG, obtained intraoperatively from six participants. We developed a new metric, the normalized differential root mean square (ndRMS), to quantify the information that is not shared between electrode pairs. The ndRMS increases with inter-electrode center-to-center distance up to 15mm, after which it plateaus. We observed differences in ndRMS between frequency bands, which we interpret in terms of oscillations in frequencies below 32Hz with phase differences between pairs, versus (un)correlated signal fluctuations in the frequency range above 64Hz. The finding that UHD recordings yield significantly higher ndRMS than HD recordings is attributed to the amount of tissue sampled by each electrode. These results suggest that ECoG densities with submillimeter electrode distances are likely justified.

No-impact trajectory design and fabrication of surface structured CBN grinding wheel by laser cladding remelting method

The structured grinding wheels have a specially designed macro or microstructure on the surface, with a relatively low average grinding force and temperature in the cutting zone and more space for chips and coolant. Most traditional grinding wheel fabrication methods, such as electroplating, sintering, and brazing, have the problems of poor abrasive grain holding strength, random abrasive distribution, or thermal deformation of the substrate. To address this, laser cladding remelting technology is introduced to fabricate the structured CBN grinding wheel. A no-impact trajectory was designed on the substrate of the grinding wheel, which can reduce the fluid friction in the channel and increase the fluid pressure at the outlet. The temperature and velocity fields of the grinding process were simulated to verify the feasibility of the designed structure theoretically. The optimal process parameters for the bonding among the metal bond, the abrasive grains, and the substrate were determined by orthogonal and full-scale factorial experiments. The chemical metallurgical reactions between CBN grain and metal bond, as well as between the metal bond and substrate, were formed, increasing the holding force of CBN grains. The method can realize the fabrication of high-strength and long-life structured grinding wheels with an orderly arrangement of abrasive grains. The micro-mechanism of fabrication was analyzed using element distribution measurement and XRD analysis.

Tailoring the Superhydrophobicity of the Nano-Silica-Coated PUA Film Through a Facile Fabrication Method of its Re-entrant Morphology

Tailoring the Superhydrophobicity of the Nano-Silica-Coated PUA Film Through a Facile Fabrication Method of its Re-entrant Morphology

Supramolecular Interfacial Assembly: Integrating Supramolecular Hosts into Polymeric Membranes through an Aqueous Interface

Efficient incorporation of supramolecular hosts in polymeric membranes can impart the overall matrix with new properties for a range of cutting‐edge applications. Here, we introduce a Supramolecular Interfacial Assembly (SIA) method for the fabrication of polymeric membranes featuring embedded macrocycles. Through harnessing the quasi‐liquid nature of the concentrated polymer solution, SIA orchestrates the homogenous spreading of macrocycles in an aqueous layer on its surface, leading to the creation of an interface between “water/water” phases, subsequently forming a cross‐linked membrane driven by supramolecular electrostatic interactions. Remarkably, compared to the traditional interfacial polymerization, SIA adheres to a “green” paradigm without the need for organic solvents. The resultant composite membrane exhibits superior performance in organic solvent nanofiltration (OSN), owing to the precise molecular sieving property provided by the macrocycles with well‐defined permanent cavities. This fabrication method holds great promise for the innovative design of composite membranes, which can greatly impact the production of smart membrane materials for advanced technology applications in the future.

A novel rapid fabrication method and in-situ densification mechanism for ceramic matrix composite

The extensive application of ceramic matrix composites has always been limited due to the long-period and expensive process. Hence, this research introduces a rapid manufacturing method named as ViSfP-TiCOP (High Viscosity Solvent-free Precursor Combined Elemental Titanium Controlled Pyrolysis). The solvent-free precursor possesses high viscosity (30 °C, 106 mPa S) and wide molecular weight distribution (Mz/Mw = 3.3), accomplishing stable loading of inorganic fillers. Simultaneously, the elementary titanium and ZrB2, as the active and inert filler, are dopped into the precursor to control the pyrolysis. The ViSfP-TiCOP technique offers a rapid method to manufacture CMCs under pressureless and low pyrolysis temperature conditions (1200 °C). Comparing to the addition of ZrB2, the precursor with titanium provides an exceptional ceramic yield of 87 wt%, leading a notable enhancement in the rate of densification. This high densification efficiency is attributed to an in-situ titanium gas-phase reaction, besides with the high degree of cross-linking and low volatile of precursor. After undergoing three cycles of impregnation-pyrolysis, the porosity of C/SiBCN–Ti was discovered to be below 10 vol%, whereas that of C/SiBCN-25 wt%ZrB2 still remained as high as 20.91 vol%. The ViSfP-TiCOP technology can provide guidance for low-cost and rapid preparation of CMCs.

Facile fabrication of degradable, serrated polyethylene diacrylate microneedles using stereolithography

Microneedles have the potential for minimally invasive drug delivery. However, they are constrained by absence of rapid, scalable fabrication methods to produce intricate arrays and serrations for enhanced adhesion. 3D printing techniques like stereolithography (SLA) are fast, scalable modalities but SLAs require non-degradable and stiff resins. This work attempts to overcome this limitation by utilizing a poly (ethylene glycol diacrylate) (PEGDA, F3) resin and demonstrating its compatibility with a commercial SLA printer. FESEM images showed high printing efficiency of customized bioinks (F3) similar to commercial resins using SLA 3D printer. Mechanical endurance tests of whole MNA showed that MNs array printed from F3 resin (485 ± 5.73 N) required considerably less force than commercial F1 resin (880 ± 32.4 N). Penetration performance of F1 and F3 was found to be 10.8 ± 2.06 N and 0.705 ± 0.03 N. In-vitro degradation study in PBS showed that MNs fabricated from F3 resin exhibited degradation after 7 days, which was not observed with the commercial F1 resin provided by the manufacturer. The histology of porcine skin exhibited formation of triangular pores with pore length of 548 μm and efficient penetration into the deeper dermal layer. In conclusion, PEGDA can be used as for fabricating degradable, serrated solid MNs over commercial resin.

Supramolecular Interfacial Assembly: Integrating Supramolecular Hosts into Polymeric Membranes through an Aqueous Interface.

Efficient incorporation of supramolecular hosts in polymeric membranes can impart the overall matrix with new properties for a range of cutting-edge applications. Here, we introduce a Supramolecular Interfacial Assembly (SIA) method for the fabrication of polymeric membranes featuring embedded macrocycles. Through harnessing the quasi-liquid nature of the concentrated polymer solution, SIA orchestrates the homogenous spreading of macrocycles in an aqueous layer on its surface, leading to the creation of an interface between "water/water" phases, subsequently forming a cross-linked membrane driven by supramolecular electrostatic interactions. Remarkably, compared to the traditional interfacial polymerization, SIA adheres to a "green" paradigm without the need for organic solvents. The resultant composite membrane exhibits superior performance in organic solvent nanofiltration (OSN), owing to the precise molecular sieving property provided by the macrocycles with well-defined permanent cavities. This fabrication method holds great promise for the innovative design of composite membranes, which can greatly impact the production of smart membrane materials for advanced technology applications in the future.

Microstructure and residual stress gradient evolution mechanism of electronic copper strip for lead frame

The miniaturization of integrated circuits has led to a shift in lead frame fabrication methods from physical stamping to chemical etching. However, this process is highly sensitive to residual stress. We investigated the gradient distribution of residual stress, microstructure, and macroscopic texture in electronic copper foils using a layer-by-layer peeling method, and proposed a novel strategy for evaluating residual stress levels. Our findings reveal that the rolling-induced residual stress exhibits a gradient distribution along the thickness direction. Specifically, from the surface to the central layer, the stress transitions gradually from tensile to compressive, with the stress type primarily influenced by metal flow during rolling. Additionally, we observed gradient variations in the S and Cube texture. Tensile stress favors the formation of Cube-texture, while compressive stress promotes S-texture development. Notably, Cube-texture can lead to strain localization during rolling, directly impacting the local residual stress levels and distribution. Furthermore, quantitative analysis of dislocation density using peak profile methods revealed a consistent trend between {111} plane dislocation density and lateral residual stress. Further investigation highlighted that dislocations and precipitates associated with {111} planes in face-centered cubic metals significantly influence residual stress, with their combined effects determining the overall stress magnitude in relation to texture, dislocations, and precipitates.

One-Step laser induced molybdenum carbide/graphene hybrid electrode for supercapacitor

Transition metal carbides (TMCs) have garnered significant attention in various energy applications owing to their outstanding conductive and electrochemical properties. Despite these advantages, challenges persist in terms of non-toxicity and efficient fabrication methods. In this study, a Mo3C2/laser-induced graphene (LIG) heterostructure was synthesized via one-step CO2 laser induced conversion process. The specific area capacitance of the Mo3C2/LIG hybrid electrode reached 23.5 mF cm−2, which is 2.5 times higher than that of pure Mo3C2 and 9 times greater than pure LIG electrodes. Moreover, the hybrid electrode exhibited robust cycling stability, maintaining 98.4 % of its initial capacitance after 10,000 charge–discharge cycles. Theoretical simulation also revealed superior hydrogen adsorption and high electrical conductivity of the Mo3C2/LIG hybrid electrode. This work presents a promising approach for developing advanced molybdenum carbide-based composites and offers an alternative strategy for enhancing the electrochemical performance of capacitive electrodes.

Excellent C-band microwave absorption properties of Ni@nitrogen-doped porous carbon nanocomposite via polymer bubbling technique

Nitrogen-doped porous carbon nanocomposites are highly sought-after materials for electromagnetic wave absorption due to their unique combination of electrical and magnetic properties. However, achieving optimal absorption performance within the critical C-band (4–8 GHz) frequency range remains a significant challenge. Ni@NPC nanocomposites, synthesized through the polymer bubbling technique, demonstrated exceptional microwave absorption (MWA) performance in the C-band. These materials exhibited a reflection loss (RL) of −65.20 dB at a thickness of 4.8 mm. When carbonized at 600 °C, a thickness of 2.0 mm achieved an effective absorption bandwidth (EAB) of 5.74 GHz. The remarkable absorption performance is ascribed to the combined effect of their porous composition and the addition of nitrogen dopants, which efficiently foster various microwave attenuation processes. Furthermore, the material’s effectiveness in real-world applications was evaluated using computer simulation technology (CST). This work highlights the potential of the one-pot fabrication method for developing high-performance MWA materials with practical applications.

Advancing Cartilage Tissue Engineering: A Review of 3D Bioprinting Approaches and Bioink Properties.

Articular cartilage is crucial in human physiology, and its degeneration poses a significant public health challenge. While recent advancements in 3D bioprinting and tissue engineering show promise for cartilage regeneration, there remains a gap between research findings and clinical application. This review critically examines the mechanical and biological properties of hyaline cartilage, along with current 3D manufacturing methods and analysis techniques. Moreover, we provide a quantitative synthesis of bioink properties used in cartilage tissue engineering. After screening 181 initial works, 33 studies using extrusion bioprinting were analyzed and synthesized, presenting results that indicate the main materials, cells, and methods utilized for mechanical and biological evaluation. Altogether, this review motivates the standardization of mechanical analyses and biomaterial assessments of 3D bioprinted constructs to clarify their chondrogenic potential.

Achieving biomimetic porosity and strength of bone in magnesium scaffolds through binder jet additive manufacturing

Magnesium (Mg) alloys are a promising candidate for synthetic bone tissue substitutes. In bone tissue engineering, achieving a balance between pore characteristics that facilitate biological functions and the essential stiffness required for load-bearing functions is extremely challenging. This study employs binder jet additive manufacturing to fabricate an interconnected porous structure in Mg alloys that mimics the microporosity and mechanical properties of human cortical bone types. Using scanning electron microscopy, micro-computed tomography, and mercury intrusion porosimetry, we found that the binder jet printed and sintered (BJPS) MgZnZr alloys possess an interconnected porous structure, featuring an overall porosity of 13.3 %, a median pore size of 12.7 μm, and pore interconnectivity exceeding 95 %. The BJPS MgZnZr alloy demonstrated a tensile strength of ~130 MPa, a yield strength of ~100 MPa, an elastic modulus of ~21.5 GPa, and an ultimate compressive strength of ~349 MPa. These values align with the ranges observed in human bone types and outperform those of porous Mg alloys produced using the other conventional and additive manufacturing methods. Moreover, the BJPS MgZnZr alloy showed level 0 cytotoxicity with a greater MC3T3-E1 cell viability, attachment, and proliferation when compared to a cast MgZnZr counterpart, since the highly interconnected 3D porous structure provides cells with an additional dimension for infiltration. Finally, we provide evidence for the concept of using binder jet additive manufacturing for fabricating Mg implants tailored for applications in hard tissue engineering, including craniomaxillofacial procedures, bone fixation, and substitutes for bone grafts. The results of this study provide a solid foundation for future advancements in digital manufacturing of Mg alloys for biomedical applications.

Material Selection for Metal Additive Manufacturing Using Multi-Criteria Decision Making Methods

Additive manufacturing has attracted attention as a new generation manufacturing method that has found widespread use in many industries in recent years due to its many advantages over traditional manufacturing methods. The materials used in metal additive manufacturing technology have a wide range. Therefore, making the ideal choice among these preferable materials is very important. Multi-criteria decision making (MCDM) techniques are reliable and effective methods in material selection processes and are effectively used in material selection processes. In this study, TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) and Additive Ratio Assessment (ARAS) methods were applied to the selection process among different criteria and materials for metal additive manufacturing. It was observed that AlSi12Cu2Fe material ranked first in the TOPSIS method, while H13 material ranked first in the ARAS method. The second place was taken by H13 material in the TOPSIS method and AlSi12Cu2Fe material in the ARAS method. A strong relationship exists between TOPSIS and ARAS methods with a Pearson correlation coefficient of 0.977. It has been concluded that it will be more effective to decide according to the nature of the technological application in the use of the materials that rank first two in TOPSIS and ARAS methods in additive manufacturing.

A novel route to produce metal or ceramic parts in space: local debinding and sintering of powdered filaments

AbstractIn-space manufacturing of polymer feedstocks has already been shown using the widely investigated filament extrusion additive manufacturing (AM) technology. Yet, polymers are only a small piece of the puzzle, and there is a growing demand to locally source metal and ceramic parts. In this manuscript, we propose a cost-effective method for in-orbit manufacturing of metal and ceramic multi-material components using highly packed powdered filaments, which need to be shaped, debinded, and sintered in sequential steps. Traditional debinding and sintering of material extrusion (MEX) AM parts are known to be time-consuming and require complex post-processing, often involving toxic debinding agents. To overcome this, a low-intensity infrared diode laser and an induction heater are coupled to a hybrid MEX system to allow full processing in situ, within the same volume. The results show that the main binder matrix can be removed across the 3D volume of the part via laser ablation of the polymeric mass, even for multi-material metal–ceramic composites. The sintered geometries further densify efficiently within the bulk due to the high-energy concentration of the induction sintering treatment, providing short processing times. Debinding and sintering locally, in the same machine, offer a simple and effective way to produce space hardware in situ, avoiding the use of consumables or part transportation to bulky equipment.

Significant Improvement in Magnetorheological Performance by Controlling Micron Interspaces with High Permeability Submicron Particles.

The shear yield strength, sedimentation stability and zero-field viscosity of magnetorheological fluids (MRFs) are crucial for practical vibration damping applications, yet achieving a balanced combination of these performances remains challenging. Developing MRFs with excellent comprehensive performance is key to advancing smart vibration damping technologies further. Theoretically, incorporating a multiscale particle system and leveraging synergistic effects between their can somewhat enhance MRFs' performance. However, this approach often faces issues such as insignificant increases in shear yield strength and excessive rise in zero-field viscosity. In response, this study employs a DC arc plasma method to synthesize a high magnetic permeability, low coercivity submicron FeNi particles, and further develops a novel CIPs-FeNi bidisperse MRFs. The introduction of submicron FeNi particles not only significantly enhances the shear2019 yield strength of MRFs under low magnetic fields but also promotes improvements in sedimentation stability and redispersibility without excessively increasing viscosity. Comprehensive performance analysis is conducted to explore the optimal content ratio, and detailed mechanisms for the enhancement of performance are elucidated through analysis of parameters such as chain-like structure, magnetic flux density and friction coefficient. Most importantly, the superior comprehensive performance combined with straightforward fabrication methods significantly enhances the engineering applicability of the CIPs-FeNi bidisperse MRFs.