Fabrication Method Research Articles

Performance analysis of microstrip patch antenna for wireless communication systems

<p>An antenna may be thought of as a temporary tool that directs radio waves for transmission or reception. Aside from being inexpensive, small, easy to manufacture, and compatible with integrated electronics, the microstrip patch antenna (MPA) offers several other benefits as well. These two methods are often seen as low-cost, adaptable, dependable, high-speed data connection choices that promote user mobility. An overview of how MPA have been used throughout the last several decades is provided in this article. It has been suggested that there are many approaches to enhance the performance of MPA, including the use of composite antennas, highly integrated antenna/array and feeding networks, operating at relatively high frequencies, and using cutting-edge manufacturing methods. Dual or multiband antennas are essential for meeting the demands of wireless services in this rapidly evolving wireless communication environment. Here is an overview of the patch antenna literature for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications.</p>

Fatigue performance and damage characterisation of ultra-thin tow-based discontinuous tape composites

Tow-cased discontinuous composites are an attractive alternative material to conventional continuous composites as they offer in-plane isotropy, enhanced manufacturability allowing to achieve complex 3D shapes with high curvatures and local reinforcement in critical areas, while also maintaining high strength and stiffness, therefore expanding the design space significantly. In addition, the use of ultra-thin tapes and optimised manufacturing methods can increase the mechanical properties even further and change the damage mechanisms. Fatigue, however, could be a limiting design factor, as the fatigue behaviour of these materials has not been fully characterised. This work presents a complete study on the fatigue response of ultra-thin tow-based discontinuous composites: fatigue S-N curves are measured, and the damage and failure mechanisms are characterised utilising optical and scanning electron microscopy. Finally, a critical interpretation of the results is also presented by comparing the performance of ultra-thin tow-based discontinuous composites against other similar fibre reinforced composites and metals. It is shown that the optimised manufacturing methods combined with low tape thickness leads to enhanced quasi-isotropic fatigue performance. In addition, the fatigue limit was raised significantly compared to other discontinuous composites, and the tow-based discontinuous composites outperformed their metal counterparts when the results were normalised with density.

Cellulose Membranes: Synthesis and Applications for Water and Gas Separation and Purification

Membranes are a selective barrier that allows certain species (molecules and ions) to pass through while blocking others. Some rely on size exclusion, where larger molecules get stuck while smaller ones permeate through. Others use differences in charge or polarity to attract and repel specific species. Membranes can purify air and water by allowing only air and water molecules to pass through, while preventing contaminants such as microorganisms and particles, or to separate a target gas or vapor, such as H2 and CO2, from other gases. The higher the flux and selectivity, the better a material is for membranes. The desirable performance can be tuned through material type (polymers, ceramics, and biobased materials), microstructure (porosity and tortuosity), and surface chemistry. Most membranes are made from plastic from petroleum-based resources, contributing to global climate change and plastic pollution. Cellulose can be an alternative sustainable resource for making renewable membranes. Cellulose exists in plant cell walls as natural fibers, which can be broken down into smaller components such as cellulose fibrils, nanofibrils, nanocrystals, and cellulose macromolecules through mechanical and chemical processing. Membranes made from reassembling these particles and molecules have variable pore architecture, porosity, and separation properties and, therefore, have a wide range of applications in nano-, micro-, and ultrafiltration and forward osmosis. Despite their advantages, cellulose membranes face some challenges. Improving the selectivity of membranes for specific molecules often comes at the expense of permeability. The stability of cellulose membranes in harsh environments or under continuous operation needs further improvement. Research is ongoing to address these challenges and develop advanced cellulose membranes with enhanced performance. This article reviews the microstructures, fabrication methods, and potential applications of cellulose membranes, providing some critical insights into processing–structure–property relationships for current state-of-the-art cellulosic membranes that could be used to improve their performance.

Welding Heat-induced Microstructural Variations in Inconel 718 Superalloy: A Comparative Investigation between Conventionally Manufactured and 3D Printed Materials

This study focuses on the microstructural evolution of Inconel 718 superalloy, a precipitation-hardened superalloy, subjected to various manufacturing processes and subsequent thermal exposures. Conventional manufacturing methods such as casting and forging were compared with modern 3D printing techniques, notably wire-arc additive manufacturing. Subsequent treatments, including solution treatment and two-stage aging, as well as bead-on-plate welding, were performed to assess their effects on the microstructure of Inconel 718. The transformations of strengthening phases such as γ′(Ni<sub>3</sub>(Al,Ti)), γ″(Ni<sub>3</sub>Nb) and intermetallic δ(Ni<sub>3</sub>Nb) phases were observed to vary significantly under different thermal cycles, and these variations in phase transformation are anticipated to lead to a degradation in mechanical performance post-welding. Additionally, thermodynamic calculations using commercial Calphad software were utilized to investigate phase transformations in the welds, providing critical insights into how manufacturing processes and thermal exposures affect the stability and distribution of microstructural features, thereby highlighting the complexities of phase dynamics in this high-performance alloy.

In English

Fullerenes are interesting objects of research in view of their promising use as a nano-sized additive to coatings, films, adsorbents, as well as active components in medicine, pharmacy, cosmetology. This paper considers the possibility of modifying commercial adsorbents - silica gel and cation-exchanger based on activated carbon with available and inexpensive linear carbon radicals. Behentrimonium chloride (C22H45(CH3)3N+Cl-) and cetyl alcohol (C16H33OН) were chosen as the latter. The obtained adsorbents were compared with a commercial sample of silica gel modified with a linear hydrocarbon radical –C18Н37. The adsorbents were described by the methods of IR spectroscopy, thermogravimetry, the main characteristics of the porous structure were determined by the method of low-temperature adsorption-desorption of nitrogen. Modification of adsorbents based on silica gel leads to a decrease in the specific surface area to 202.4 and 236.5 m2/g and the total pore volume to 0.32 and 0.39 cm3/g, which is almost 2 half source material. Increasing the fraction of micropores contributes to better separation rates of large molecules. Treatment of cation-exchanger based on activated carbon by cation modifier leads to a significant decrease in the specific surface area, as well as to an increase in the size of pores with the predominant formation of mesopores. It is shown that the modification of silica gel is carried out both through silanol and siloxane groups, in contrast to the commercial sample of silica gel. The approximate number of modifier groups on the surface of the original SiO2 matrix was estimated, which is one modifier group ~ per 11 SiO2 molecules. To study the behavior of adsorption of C60, C70 fullerenes and their mixtures on adsorbents, column experiments were carried out with changes in the geometrical parameters of the column and the initial concentrations of the solutions. The results showed that the modified silica gels are potential adsorbents for the separation of a mixture of fullerenes with a ratio of 65/25. Silica gel modified with cetyl alcohol C16H33OH showed the best separation efficiency. By the help of an adsorbent, it is possible to separate C60 - 90.52 % from a less concentrated solution and 87.26 % from a more concentrated solution. To increase the purity of the product, it is necessary to pass the solution through the sorbent 2–3 times. The competitive capability of the proposed modified silica gels, together with economic efficiency, ease of modification, and the possibility of fullerene separation characterize the proposed adsorbents as potential materials for practical application. Due to the significantly lower cost and simpler manufacturing methods, the proposed adsorbents can be used for separation at a large scale.

Fabrication of Customized Bioactive Scaffolds for the Repair of Bone Defects using 3d Printing

Fabrication of Customized Bioactive Scaffolds for the Repair of Bone Defects using 3d Printing

GALVANOPLASTIC ACCESSORIES FOR CLOTHING, BAGS AND SHOE

The paper considers the peculiarities of design of fittings for fashionable clothing, haberdashery and footwear. It is noted that in the current conditions of global competition between manufacturers, the use of original solutions in the design of footwear, clothing and haberdashery products, based on the use of new materials, new methods of design and manufacturing, contributes to the successful promotion of goods in the market by expanding the range, creating author’s and mass ultra-fashionable products with unique aesthetic properties. Differences in operating conditions of different groups of fittings and requirements to their performance characteristics are noted. Possible technologies and materials for their manufacture are considered. It is shown that a possible alternative to the technologies used in their production is galvanoplastic shaping of fittings, which has a number of undeniable advantages.

Large-scale fabrication of thulium iron garnet film with perpendicular magnetic anisotropy using RF magnetron sputtering

Abstract Large-scale fabrication of thulium iron garnet (TmIG) films on GGG substrates, with a total area of 25 cm2, has been demonstrated by rotating substrate holder during on-axis sputtering. By optimizing the growth parameters based on the pressure and flow rate of the oxygen ratio, a Tm/Fe ratio of 0.65 was obtained, which is close to the stoichiometry of TmIG. The increase in post-annealing temperature has induced the growth of the TmIG structure by the strain of the lattice constant mechanism. At the highest post-annealing temperature, the crystal structure of TmIG (444) and the perpendicular magnetic anisotropy (PMA) were obtained. This result demonstrates the potential method for large-scale fabrication of TmIG film with PMA.

Underwater fluid-driven soft dock for dynamic recovery of AUVs with improved pose tolerance

Recovering autonomous underwater vehicles (AUVs) by a mobile platform is a complex challenge. Traditional docking stations require strict pose deviation from the underwater vehicle. To overcome this issue, we propose a novel solution: an in-situ fluid-driven soft dock. This system comprises three soft robotic manipulators that possess guiding, capturing, and securing functionalities, respectively. We present the design, fabrication, and control methods for each manipulator considering the requirements of underwater docking operations. The theoretically allowable docking pose deviation range during AUV docking is analyzed. Additionally, the required force of soft grippers was evaluated through simulation and equivalent experimental tests. To enable dynamic recovery of AUVs while the soft robotic manipulators remain mobile on the experimental platform, we introduce a hydraulic control method based on attitude and pressure feedback. The test results indicate that the designed soft manipulators can operate and maintain good sealing performance under an external pressure of no less than 11 MPa. Moreover, the soft dock successfully recovered and secured AUVs of two different diameters in 20 dynamic tests, achieving a 90% success rate with a maximum AUV velocity of 1.6 m/s.

Nanostructured ZnO‐CQD Hybrid Heterostructure Nanocomposites: Synergistic Engineering for Sustainable Design, Functional Properties, and High‐Performance Applications

AbstractHybrid nanocomposites integrating nanostructured zinc oxide (ZnO) and carbon quantum dots (CQDs) with designed heterostructures possess exceptional optical and electronic properties. These properties hold immense potential for advancements across diverse scientific and technological fields. This review article investigates the synthesis, properties, and applications of ZnO‐CQD heterostructure nanocomposites. Recent breakthroughs in fabrication methods are examined, including hydrothermal, microwave‐assisted, and eco‐friendly techniques. Key preparation methods such as sol‐gel, co‐precipitation, and electrochemical deposition are discussed, emphasizing their role in controlling heterostructure formation. This review analyses the impact of heterostructures on optical and electronic properties, such as fluorescence, photoluminescence, and photocatalytic activity. Synergistic interactions between ZnO and CQDs within heterostructures are highlighted, demonstrating how they lead to substantial performance improvements. Applications of ZnO‐CQD heterostructures span solar cells, LEDs, photodetectors, water purification, antimicrobial treatments, gas sensing, catalysis, biomedical imaging, drug delivery, environmental sensing, and energy storage. Insights are provided into refining synthesis methods, enhancing characterisation techniques, and broadening the application landscape. Challenges like stability are addressed, along with strategies for optimised performance and practical implementation. This comprehensive review offers a thorough understanding of ZnO‐CQD heterostructure nanocomposites, emphasising their significance within materials science and engineering. By addressing core concepts and future directions, it lays a foundation for continued innovation in this dynamic field.

Antibody‐Targeted Phytohormone Delivery Using Foliar Sprayed Silk Fibroin Pickering Emulsions

AbstractEfficient delivery systems based on biopolymers offer new solutions to enhance food security by boosting crop yield and quality while decreasing agrochemical input and mitigating environmental impact. Herein, a novel Pickering emulsion fabrication method that utilizes antibody‐functionalized silk fibroin to enhance foliar adhesion upon application for efficient agrochemicals delivery is reported. Silk fibroin microparticles (SFMPs) stabilize both nonpolar and polar oil‐in‐water Pickering emulsions, revealing the cooperative function of both oil phase polarity and aqueous media pH in stabilization, where phytohormones addition influenced the stability and oil‐water contact angle. Phytohormone‐containing Pickering emulsions are functionalized with anti‐pectic polysaccharide (alpha‐1,5‐arabinan) antibody labeled SFMPs through adsorption, to enhance droplet adhesion to leaf cuticle surface. As a proof‐of‐concept, Pickering emulsion containing 0.1 mM jasmonic acid (JA) is applied to Arabidopsis thaliana via foliar spraying. Following washing, treatment with antibody‐functionalized Pickering emulsion increased trichome numbers on young leaves by 20% and 3%, when compared to nonencapsulated JA and nonfunctionalized emulsions, respectively. The functionalized Pickering emulsion stabilized by SFMPs exhibited no plant toxicity and biodegraded 50 wt.% in 7 days, catalyzed by Streptomyces griseus protease. Results highlight the potential of SFMP‐stabilized oleic acid‐in‐water Pickering emulsion as a sustainable and biodegradable solution to precisely deliver agrochemicals through foliar spray.

3D Printing of Ordered Mesoporous Silica Using Light‐Induced Sol‐Gel Chemistry

AbstractMesoporous ceramic materials used in applications such as catalysis, filtration, or sensing, are usually hierarchically structured. Thereby, their structural hierarchy is often inherently related to the manufacturing methods and cannot be independently locally designed along all length scales. This study combines light‐based additive manufacturing and bottom‐up light‐induced self‐assembly (LISA) sol‐gel chemistry to engineer hierarchically structured porous silica from the nanoscale to the macroscopic object geometry. A LISA‐based printing solution that enables printing of ordered mesoporous silica with geometrically complex shapes by using a commercially available digital light processing (DLP)‐based 3D printer is presented. This approach exploits the self‐assembly process of block copolymer mesopore templates, such as Pluronic P123, and hydrolysis and condensation of silica precursors upon irradiation in the 3D printer to shape mesoporous silica objects. Furthermore, different resins are added to the LISA solution to print 3D silica‐resin objects. Mesoporous silica objects up to 10 mm in size, consisting of ordered mesopores with diameters around 5 nm and having high specific surface areas of ≈400 m2 g−1 are successfully printed with a fast and easy post‐processing.

Concrete gyroid: an additive manufacturing (AM) method to 3D print gyroid geometries with a cementitious material

Concrete gyroid: an additive manufacturing (AM) method to 3D print gyroid geometries with a cementitious material

Ultrasensitive composite electrochemical sensor with printed wrinkled CNTs nanostructure for simultaneous detection

Combining biomimetic and 3D printing has created new opportunities for the manufacture of electrochemical sensors. Dopamine (DA) and Uric acid (UA) are common body electroactive substances, and their detection is important for diagnosing metabolic diseases. Metal electrochemical sensors have limitations in sensitivity and selectivity due to their smooth 2D structures, which make it challenging to capture comprehensive electrochemical information. Here, inspired by taste buds, an ultrasensitive CNT-Pt composite electrochemical sensor, including a printed biomimetic wrinkled CNTs film, was prepared for simultaneous detection of DA and UA. Nanoscale Pt electrode was prepared by UV-LIGA process and the wrinkled CNTs nanofilm was fabricated by thermally assisted electrohydrodynamic jet (E-Jet) printing. CNT lines of 3∼58 μm, droplets of 4 μm and 2D array structures have been printed. The enhanced sensing mechanism of wrinkled CNTs nanofilm was analyzed theoretically. The nanoscale wrinkled morphology (nanofolds∼50 nm) and hydrophilicity (CÃ20°) of printed wrinkled CNTs nanofilm were analyzed. The anodic peak potential for UA was observed to range from 0.429 V to 0.489 V for the conventional Pt electrochemical sensor, whereas it ranged from 0.205 V to 0.276 V for the CNT-Pt composite electrochemical sensor. The detection performance of CNT-Pt composite electrochemical sensor was improved by ∼40 % contrast with Pt electrochemical sensor. The prepared composite electrochemical sensor can effectively recognize DA, UA and AA. From analysis, the peak value of AA was not obvious, the peak values of DA and UA were 0.096 V and 0.265 V. The composite electrochemical sensor successfully eliminated the detection interference caused by AA in detecting DA and UA. The nanoscale composite electrochemical sensor and its hybrid manufacturing method provide great potential for electrochemical testing applications.

Comparison of GeSn alloy films prepared by ion implantation and remote plasma-enhanced chemical vapor deposition methods

Thin films of germanium-tin (GeSn) alloy with Sn content well above its equilibrium solubility limit in Ge are produced using both remote plasma-enhanced chemical vapor deposition (RPECVD) directly on silicon substrates and ion implantation of Sn into Ge. For RPECVD, the growth temperature of 302 °C resulted in fully relaxed GeSn alloys with high defect density, principally threading dislocations related to the large lattice mismatch between Si and GeSn. For the implantation case, pulsed laser melting was used to melt and crystallize the GeSn layer on a time scale of a few tens of nanoseconds. The resulting GeSn layers were also relaxed and defective, presumably again as a result of lattice mismatch with the underlying Ge lattice. However, the nature of the defects was quite different to the RPECVD method, whereby the line defects were not threading dislocations but stackinglike defects, which developed into arrays of these defects in the high Sn content region close to the surface. For the purpose of comparing RPECVD and ion-implantation methods, alloy films of similar thickness (400–450 nm) and Sn content (4.5–6.5 at. %) were examined. Film parameters (thickness, Sn content, Sn solubility, and segregation), as well as film quality and defect structures, were examined for both fabrication methods using several analytical techniques. This comparison provided us with a better physical understanding of our GeSn films and will help inform future growth/fabrication strategies targeted at minimizing defects formed in the GeSn films for the realization of optoelectronic devices.

Efficient Fabrication of Bioinspired Flexible Pressure Sensors via Electrohydrodynamic Jet Printing Method.

The bioinspired microdevices have made significant strides in various applications including human motion and health detection. However, the facile and highly efficient fabrication approach of flexible pressure sensors remains a great challenge. Herein, inspired by the gecko's foot structure, a flexible pressure sensor with microdomes structures was one-step fabricated by tip-assisted on-demand electrohydrodynamic jet (EHD-jet) printing method. Ascribed to the interlocking electrodes with microdome structure substantially enlarged 3D deformation rates. When the microdromes structure is under pressure, the resistivity of the CNTs film coated on the surface of the microdomes structure will change remarkably. By using the combined effect of assisted tip and ring focusing electrode, the influence and constraints on microstructure fabrication caused by substrate material and morphology are minimized. The desired uniform structures can be adjusted rapidly by changing the printing parameters and liquid properties. The high length-height ratio (0.64) of microdomes, notably enhances the sensitivity, the minimum detection limit is 2Pa and the response time is 40ms. Finally, the bionic flexible sensor shows excellent performance in capable of detecting pressure, sound vibrations, and human motion. This work introduces a previously unexplored method for the high-efficiency fabrication of micro-nano patterns for bionic flexible sensors, with potential applications in wearable devices and human health detection. This article is protected by copyright. All rights reserved.

An asymmetric super-wetting Janus PVDF oil-water separation membrane fabricated by a simple method on a non-woven substrate

Membrane separation technology is an important method of treating oily wastewater with great potential for development. However, preparation of membranes for efficiently separating complex oil-water mixtures continues to be challenging. In this study, a strategy for efficient construction of asymmetric wetting surfaces was designed, and successfully prepared an asymmetric super wetting Janus polyvinylidene fluoride (PVDF) modified separation membrane to separate complex oil-water emulsion. The composite PVDF membrane was prepared using a non-woven fabric substrate and phase conversion method. Subsequently, composite membrane was rapidly hydrophilic modified on one side using tannic acid and 3-aminopropyltriethoxysilane under the strong oxidizing effect of oxidant sodium periodate. Then non-woven fabric substrate was peeled off to obtain a Janus PVDF modified separation membrane. The front and back sides of the separation membrane have highly asymmetric micromorphology and wettability. The front side has hydrophilic/underwater oleophobic wettability (with a water contact angle of 31°). The separation efficiency of oil-in-water emulsion is up to 99.5%, while the back side has super lipophilic/underoil hydrophobic wettability (with a water contact angle of 131°). The separation efficiency of water-in-oil emulsion is up to 98.6%, improving the efficiency of oil in water separation and application range.

Propelling Minimally Invasive Tissue Regeneration With Next-Era Injectable Pre-Formed Scaffolds.

The growing aging population, with its associated chronic diseases, underscores the urgency for effective tissue regeneration strategies. Biomaterials play a pivotal role in the realm of tissue reconstruction and regeneration, with a distinct shift toward minimally invasive (MI) treatments. This transition, fueled by engineered biomaterials, steers away from invasive surgical procedures to embrace approaches offering reduced trauma, accelerated recovery, and cost-effectiveness. In the realm of MI tissue repair and cargo delivery, various techniques are explored. While in situ polymerization is prominent, it is not without its challenges. This narrative review explores diverse biomaterials, fabrication methods, and biofunctionalization for injectable pre-formed scaffolds, focusing on their unique advantages. The injectable pre-formed scaffolds, exhibiting compressibility, controlled injection, and maintained mechanical integrity, emerge as promising alternative solutions to in situ polymerization challenges. The conclusion of this review emphasizes the importance of interdisciplinary design facilitated by synergizing fields of materials science, advanced 3D biomanufacturing, mechanobiological studies, and innovative approaches for effective MI tissue regeneration.

Effect of rapid thermal annealing on DC performance of Mg0.30Zn0.70O/Cd0.15Zn0.85O MOSHFET

This study focuses on a cost-effective method for fabrication of a metal oxide semiconductor-heterostructure field effect transistor (MOSHFET) based on MgZnO/CdZnO (MCO) using dual ion beam sputtering (DIBS), in contrast to the more expensive epitaxial growth system. The MOSHFETs developed in this research exhibit notable characteristics, such as a substantial two-dimensional electron gas (2DEG) transconductance (∼2.6 mS), a high ION/IOFF response ratio in the order of 108, and minimal gate leakage current. Furthermore, we explore the impact of rapid thermal annealing (RTA) on the drain current at various temperatures (600 °C and 800 °C). The results indicate a fourfold improvement in drain current compared to unannealed conditions, primarily attributed to reduced contact resistance and no degradation in term of MgZnO/CdZnO structure. Additionally, an analysis of post-RTA treatment under a nitrogen (N2) atmosphere on gate leakage current is presented. The investigation spans temperatures ranging from 400 °C to 800 °C, revealing that above 600 °C (gate leakage at 400 °C–600 °C is around ∼10−9 A), gate leakage in HFET is augmented by one order of magnitude (∼10−8 A) due to a phase change in the dielectric. These findings underscore the feasibility of DIBS-grown MCO MOSHFETs as an economical solution for the mass production of switching devices and sensors.

One-step formation of polymorphous sperm-like microswimmers by vortex turbulence-assisted microfluidics

Microswimmers are considered promising candidates for active cargo delivery to benefit a wide spectrum of biomedical applications. Yet, big challenges still remain in designing the microswimmers with effective propelling, desirable loading and adaptive releasing abilities all in one. Inspired by the morphology and biofunction of spermatozoa, we report a one-step formation strategy of polymorphous sperm-like magnetic microswimmers (PSMs) by developing a vortex turbulence-assisted microfluidics (VTAM) platform. The fabricated PSM is biodegradable with a core-shell head and flexible tail, and their morphology can be adjusted by vortex flow rotation speed and calcium chloride solution concentration. Benefiting from the sperm-like design, our PSM exhibits both effective motion ability under remote mag/netic actuation and protective encapsulation ability for material loading. Further, it can also realize the stable sustain release after alginate-chitosan-alginate (ACA) layer coating modification. This research proposes and verifies a new strategy for the sperm-like microswimmer construction, offering an alternative solution for the target delivery of diverse drugs and biologics for future biomedical treatment. Moreover, the proposed VTAM could also be a general method for other sophisticated polymorphous structures fabrication that isn’t achievable by conventional laminar flow.