Preparation Method Research Articles

Processability and Separability of Commercial Anti-Corrosion Coatings Produced by In Situ Hydrogen-Processing of Magnetic Scrap (HPMS) Recycling of NdFeB.

The recycling of NdFeB magnets is necessary to ensure a reliable and ethical supply of rare earth elements as critical raw materials. This has been recognized internationally, prompting the implementation of large-scale legislative measured aimed at its resolution; for example, an ambitious recycling quote has been established in the Critical Raw Materials Act Successful recycling in sufficient quantities is challenged by product designs that do not allow the extraction and recycling of these high-performance permanent magnets without excessive effort and cost. This is particularly true for smaller motors using NdFeB magnets. Therefore, methods of recycling such arrangements with little or no dismantling are being researched. They are tested for the hydrogen-processing of magnetic scrap (HPMS) method, a short-loop mechanical recycling process. As contamination of the recycled material with residues of anti-corrosion coatings, adhesives, etc., may lead to downcycling, the separability of such residues from bulk magnets and magnet powder is explored. It is found that the hydrogen permeability, expansion volume, and the chosen coating affect the viable preparation and separation methods as recyclability-relevant design features.

Patterned Micro Flexible Supercapacitors based on the Rapid Transfer-Printing Method.

Developing a simple and rapidly preparative method for patterned flexible supercapacitors is essential and indispensable for the swift advancement of portable devices integrated with micro devices. In this study, we employed a cost-effective and rapid fabrication method based on transfer-printing technology to produce patterned micro flexible supercapacitors with various substrates. The resulting flexible micro supercapacitors not only allow for customized patterns with strong flexibility and resistance to bending, while maintaining a certain level of performance, but also facilitate the creation of diverse circuits to tailor voltage and current to specific requirements. Patterned micro flexible supercapacitors with a thickness of 0.02 mm, based on accordion-like Ti3C2Tx MXene materials coated on a substrate, demonstrate a specific capacitance of 142.7 mF cm-2 at 0.5 mA cm-2. The devices exhibit satisfactory capacitance retention (91% after 5000 cycles) and superb mechanical flexibility (71% capacitance retention at 180° bending after 2000 cycles). At a power density of 2.9 mW cm-2, the energy density of the sandwich structure device reaches 126.8 μWh cm-2. This study is expected to contribute new ideas for the design and preparation of patterned flexible supercapacitors.

Strong Bases and beyond: The Prominent Contribution of Neutral Push-Pull Organic Molecules towards Superbases in the Gas Phase.

In this review, the principles of gas-phase proton basicity measurements and theoretical calculations are recalled as a reminder of how the basicity PA/GB scale, based on Brønsted-Lowry theory, was constructed in the gas-phase (PA-proton affinity and/or GB-gas-phase basicity in the enthalpy and Gibbs energy scale, respectively). The origins of exceptionally strong gas-phase basicity of some organic nitrogen bases containing N-sp3 (amines), N-sp2 (imines, amidines, guanidines, polyguanides, phosphazenes), and N-sp (nitriles) are rationalized. In particular, the role of push-pull nitrogen bases in the development of the gas-phase basicity in the superbasicity region is emphasized. Some reasons for the difficulties in measurements for poly-functional nitrogen bases are highlighted. Various structural phenomena being in relation with gas-phase acid-base equilibria that should be considered in quantum-chemical calculations of PA/GB parameters are discussed. The preparation methods for strong organic push-pull bases containing a N-sp2 site of protonation are briefly reviewed. Finally, recent trends in research on neutral organic superbases, leaning toward catalytic and other remarkable applications, are underlined.

Non-oxidative ethane dehydrogenation reaction over molybdenum and chromium incorporated MgO encapsulated carbon-core catalysts in microwave reactor

AbstractChromium and molybdenum incorporated MgO and MgO–C catalysts were synthesized for hydrogen production from a non-oxidative ethane dehydration reaction. Hydrogen production studies were carried out using a microwave-heated reactor system. The study investigated the effects of reaction temperature, type of active metal, and catalyst preparation method (physical mixture or core–shell structure) on hydrogen selectivity and ethane conversion during dehydrogenation reactions. The results showed that the optimal reaction temperature for the non-oxidative ethane dehydration reaction was 450 °C. Above this temperature, the selectivity of undesired byproducts increased. Catalysts containing molybdenum exhibited higher ethane conversion. Moreover, a comparison of MgO–C-supported catalysts with MgO-supported catalysts revealed that the core–shell catalysts exhibited superior ethane conversion. Notably, the 5Mo@MgO–C catalyst demonstrated exceptional catalytic activity, achieving a high ethane conversion rate of 72% along with excellent stability.

Water‐based Polyurethane Heating Film with Double‐Layer Conductive Network for a Rapid Electrothermal Response

Carbon‐based composite materials have garnered widespread attention in the field of Personal Thermal Management (PTM). In these applications, constructing conductive fillers with a highly cross‐linked network is key to achieving the rapid electrothermal conversion of materials. Herein, a novel carbon‐based composite material was successfully developed using screen printing technology, with a waterborne polyurethane (WPU) matrix embedded with carbon nanotubes (CNTs) and calcein‐modified graphene nanosheets (CAG). Due to the strong π‐π conjugation interactions present in the highly cross‐linked carbon‐based network, the resulting CAG‐CNTs/WPU composite forms a three‐dimensional conductive network, which not only demonstrates a significant synergistic effect but also facilitates efficient transport of electrons and phonons. Experimental results show that the CAG‐CNTs/WPU composite possesses excellent electrothermal conversion properties and an upper high thermal conductivity (3.10 W·m‐1·K‐1). At a low voltage of 5 V, the composite exhibited a rapid response, increasing to 50 °C in 20 s. This research not only highlights the importance of adopting environmentally friendly preparation methods but also emphasizes the synergistic role played by two‐dimensional graphene nanosheets and one‐dimensional carbon nanotubes in building an efficient three‐dimensional electrothermal network, which has significant scientific and application value in advancing PTM applications.This article is protected by copyright. All rights reserved.

Research Progress on the Preparation Methods for and Flame Retardant Mechanism of Black Phosphorus and Black Phosphorus Nanosheets

Black phosphorus and black phosphorus nanosheets are widely used in the flame retardant field because of their excellent properties, but the immature preparation methods have resulted in extremely high preparation cost, which greatly limits their development and application. In this paper, various preparation methods of black phosphorus and black phosphorus nanosheets are described in detail, the advantages and disadvantages of each method are analyzed in depth, the flame-retardant mechanism and application of black phosphorus and black phosphorus nanosheets in flame retardants are discussed, and the subsequent development direction of black phosphorus and black phosphorus nanosheets is proposed.

Modern innovations in the provision and efficient application of 2D inorganic nanoscale materials

Abstract Two-dimensional nanoscale materials (2D NMs) have exceptional physical characteristics, distinctive structures, and customizable surface chemistry. They consist of infinite transverse dimensions of near-atomic thickness or atoms. They promise advancements in catalysis, renewable energy, and sensing. An extensive summary of the most recent research results on the creation and use of 2D NMs is provided in this work. It is possible to modify the characteristics of these multi-layered materials by means of chemical and physical manipulations. Due to their layer-dependent electrical properties, certain 2D layered inorganic nanomaterials such as MoS2, WS2, and SnS2 have recently been created and used in a variety of applications, including new sensors. In addition, the article delves into the difficulties confronted by sectors reliant on nanotechnology as well as the potential future uses of nanostructures coupled with electrochemical systems. The article begins by outlining the typical “top-down” and “bottom-up” approaches for synthesizing 2D NMs. These approaches include hydrothermal procedures, ion intercalation, mechanical exfoliation, liquid-phase exfoliation assisted by ultrasonic waves, and chemical vapor deposition. 2D NMs are the focus of this work because of their potential applications in gas sensing, photocatalysis, electrocatalysis, photo detection, and electromagnetic wave absorption. In addition, the study predicts patterns of future development and possible issues with 2D NMs based on existing studies. Increased demand for cost-effective, environmentally friendly, and highly connected products is propelling the ongoing research and development of these high-performance materials. This research is significant since it summarizes, in one place, the most recent advances in 2D NM preparation methods and applications.

Pulsed lavage is associated with better quality of bone-cement-implant interface in knee arthroplasties (TKA/UKA) compared to syringe lavage in vitro; however, clinical data are missing: A systematic review.

The purpose of this systematic review is to analyse the available literature to ascertain the optimal method of bone preparation to improve the quality of bone-cement-implant interface with either pulsed lavage or syringe lavage in both total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA). A comprehensive search was conducted across MEDLINE, Scopus and Embase databases until July 2023. Both inclusion and exclusion criteria were clearly stated and used to identify all the published studies. Subsequent screening throughout the title, abstract and full text was made, followed by complete critical appraisal and data extraction. This sequential process was performed by two reviewers independently and summarised following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines). A quality assessment of the systematic review was performed according to the Quality Appraisal for Cadaveric Studies scale (QUACS), reaching a quality level ranging from 69% to 85%. A total of 10 articles, out of 47, nine biomechanical cadaveric studies and one human clinical study were analysed. A total of 196 UKA tibial components, 74 patellar components, 36 TKA tibial components and 24 UKA femoral components were retrieved, and a high level of heterogeneity resulted overall. The pulsed lavage group showed better cement penetration and higher pull-out force than the syringe lavage group; a higher interface temperature was also found in the pulsed lavage group. No differences were found regarding tension ligament forces between the groups. Our systematic review suggests that pulsed lavage is superior to syringe lavage in terms of the quality of bone-cement-implant interface in knee arthroplasties (TKA/UKA). However, translation of these results from cadaveric studies to individual clinical settings may be hazardous; therefore, clinical in vivo prospective studies are highly needed. PROSPERO CRD number CRD42023432399. Level III.

Alcohol-Based Chlorhexidine and Potassium Sorbate Rub Strengthens the Effectiveness of Traditional Hand Scrubbing and Improves Long-Lasting Effectiveness-Evaluation of Hand Preparation Protocols According to EN 12791.

Despite the advantages of surgical handrub in terms of the ease of application and effectiveness, chlorhexidine (CHG)-based hand scrubbing remains the preferred method for surgical hand preparation. However, it does not systematically meet the non-inferiority requirement of the European norm (EN) 12791 with respect to n-propanol (the reference product) and does not provide the sustained efficacy expected for these long-lasting agents. Commercially available alcohol-based products have also failed to demonstrate sustained efficacy according to EN 12791. Multi-step protocols enhance the efficacy of hand scrubbing, yet their extended disinfection duration might diminish their allure for healthcare professionals. In this study, we show that hand scrubbing with CHG 4% followed by a 1 min rubbing with the novel formulation of ethanol (Et) 70%/CHG 3% plus 0.3% potassium sorbate food additive (PS) meets the non-inferiority requirement and demonstrates sustained efficacy when tested according to EN 12791. The immediate and 3 h effect of this protocol was significantly higher than that of n-propanol and the homologous disinfection protocol without PS (CHG 4% hand scrub plus Et 70%/CHG 3% rub), demonstrating that the inclusion of PS confers a notable residual effect. We speculate that this non-volatile ingredient acts synergistically with CHG. This promising combination represents an alternative method for the development of new disinfection strategies.

An Overview of Transferosomal Technology

Abstract: Ever since the invention of liposomes by Bangham in 1963, researchers have been fascinated by the vesicular carriers. Liposomes and niosomes have been used extensively by researchers for various routes such as oral and nasal. However, lately, it has been understood that traditional liposomes are not very significant when it comes to penetration. The use of nanovesicles in transdermal drug delivery systems has been enhanced exponentially ever since the discovery of ultra- deformable liposomes known as transfersomes or transferosomes. Transferosomes have numerous advantages, such as biocompatibility, biodegradability, flexibility, and deformability, so that they can pass through narrow constrictions. They have good entrapment efficiency and can act as a depot to sustain the release of drugs. The methods of preparation include the rotary film evaporation method, reverse phase evaporation method, vortexing sonication method, ethanol injection method, and freeze-thaw method. Transfersomes are characterized by particle size, zeta potential, polydispersity index, surface morphology, and encapsulation efficiency. Transferosomes have been successfully exploited for the enhancement of efficacy of many drugs like Hydroquinone, Itraconazole, Ivabradine, lornoxicam, minoxidil etc., via transdermal and nasal routes. The technology is easy to scale up. Consequently, it can be inferred that transfersomes are the future of transdermal drug delivery systems.

Facilitating Atom Probe Tomography of 2D MXene Films by In Situ Sputtering.

2D materials are emerging as promising nanomaterials for applications in energy storage and catalysis. In the wet chemical synthesis of MXenes, these 2D transition metal carbides and nitrides are terminated with a variety of functional groups, and cations such as Li+ are often used to intercalate into the structure to obtain exfoliated nanosheets. Given the various elements involved in their synthesis, it is crucial to determine the detailed chemical composition of the final product, in order to better assess and understand the relationships between composition and properties of these materials. To facilitate atom probe tomography analysis of these materials, a revised specimen preparation method is presented in this study. A colloidal Ti3C2Tz MXene solution was processed into an additive-free free-standing film and specimens were prepared using a dual beam scanning electron microscope/focused ion beam. To mechanically stabilize the fragile specimens, they were coated using an in situ sputtering technique. As various 2D material inks can be processed into such free-standing films, the presented approach is pivotal for enabling atom probe analysis of other 2D materials.

Extrusion-based bioprinting: considerations toward gelatin-alginate bioink

Purpose This study aims to develop a simplified bioink preparation method that can be applied to most hydrogel bioinks used in extrusion-based techniques. Design/methodology/approach The parameters of the bioprinting process significantly affect the printability of the bioink and the viability of cells. In turn, the bioink formulation and its physicochemical properties may influence the appropriate range of printing parameters. In extrusion-based bioprinting, the rheology of the bioink affects the printing pressure, cell survival and structural integrity. Three concentrations of alginate-gelatin hydrogel were prepared and printed at three different flow rates and nozzle gauges to investigate the print parameters. Other characterizations were performed to evaluate the hydrogel structure, printability, gelation time, swelling and degradation rates of the bioink and cell viability. An experimental design was used to determine optimal parameters. The analyses included live/dead assays, rheological measurements, swelling and degradation. Findings The experimental design results showed that the hydrogel flow rate substantially influenced printing accuracy and pressure. The best hydrogel flow rate in this study was 10 ml/h with a nozzle gauge of 18% and 4% alginate. Three different concentrations of alginate-gelatin hydrogels were found to exhibit shear-thinning behavior during printing. After seven days, 46% of the structure in the 4% alginate-5% gelatin sample remained intact. After printing, the viability of skin fibroblast cells for the optimized sample was 91%. Originality/value This methodology offers a straightforward bioink preparation method applicable to the majority of hydrogels used in extrusion-based procedures. This can also be considered a prerequisite for cell printing.

Developing a Novel Hybrid Nanofluid Preparation Method Using the Droplet Generation Method: Predicting the Thermal Conductivity, Viscosity, and Magnetic Properties Compared to the Conventional Two-Step Method

Developing a Novel Hybrid Nanofluid Preparation Method Using the Droplet Generation Method: Predicting the Thermal Conductivity, Viscosity, and Magnetic Properties Compared to the Conventional Two-Step Method

Unveiling physico-mechanical and acoustical characteristics of fly ash geopolymers through the synergistic impact of density and porosity

This paper investigates the physico-mechanical and acoustic properties of fly ash geopolymers via casting and pressing methods. The existing research lacks comprehensive insight into the relationship between variations in geopolymer density and their impacts on both physico-mechanical properties and sound insulation and absorption capabilities. Geopolymers, as sustainable construction materials, are pivotal in mitigating noise and providing structural strength. To surpass these limitations and achieve either higher or lower densities in geopolymers, alternative approaches are necessary. Casting (non-foamed and foamed with 1.0, 2.0 and 3.0 foam-to-geopolymer paste ratio) and pressing methods were employed to produce a range of geopolymer densities between 1400 kg/m3 – 2200 kg/m3. The pressing method produced a highly dense geopolymer with an excellent compressive strength of 116 MPa. While the lightest geopolymer produced by adding a foaming agent had a compressive strength of 13 MPa. Good sound transmission loss (66.1 dB) was achieved by highly dense pressed geopolymers. Highly porous geopolymers achieved an excellent sound absorption coefficient of 0.79. The density variation and preparation methods greatly affected the pore size and distribution which subsequently affected the acoustical properties of the geopolymers. Manipulating the density and porosity of the geopolymers is essential for creating spaces with optimal acoustics to meet building codes and noise control regulations.

Bioinspired Slippery Surfaces for Liquid Manipulation from Tiny Droplet to Bulk Fluid.

Slippery surfaces, which originate in nature with special wettability, have attracted considerable attention in both fundamental research and practical applications in a variety of fields due to their unique characteristics of superlow liquid friction and adhesion. Although research on bioinspired slippery surfaces is still in its infancy, it is a rapidly growing and enormously promising field. Herein, a systematic review of recent progress in bioinspired slippery surfaces, beginning with a brief introduction of several typical creatures with slippery property in nature, is presented. Subsequently,this review gives a detailed discussion on the basic concepts of the wetting, friction, and drag from micro- and macro-aspects and focuses on the underlying slippery mechanism. Next, the state-of-the-art developments in three categories of slippery surfaces of air-trapped, liquid-infused, and liquid-like slippery surfaces, including materials, design principles, and preparation methods, are summarized and the emerging applications are highlighted. Finally, the current challenges and future prospects of various slippery surfaces are addressed.

Application of the AHP-QFD methodology in the sustainability analysis of a trifunctional adsorbent for inorganic micropollutants from contaminated water

An alternative approach to addressing water pollution is through the development of adsorbent materials. Na-jarosite is a promising material capable of removing simultaneously multiple ions from contaminated water. Employing four Quality Functional Deployment (QFD) matrices alongside the hierarchical analysis process (AHP) methodology, this study aimed to select materials, preparation methods, equipment, and processing conditions of Na-jarosite to remove As(V), Pb(II) and F (-) from contaminated water. The analysis of QFD matrices 1 and 2 identified electrical heating as the optimal method for synthesizing Na-jarosite, exhibiting removal capacities of removal capacity of 65.56 mg g−1 for As(V), 94 mg g−1 for Pb(II) and 2.45 mg g−1 for F(-). Rotating disc granulation was chosen for adsorbent formation, demonstrating environmental viability based on E Factor (0.6 kg of waste) and Eco scale (89) indicators. Further analysis of the QFD 3 matrix allowed the selection of essential equipment, including an electrical heating oven, a rotating disc granulator, and an extended tray for synthesis, granulation, and drying processes, respectively. Additionally, the QFD 4 matrix analysis identified drying the adsorbent at temperatures below 100 °C as a critical parameter for effective adsorbent formation. QFD and AHP analyses findings highlight the potential of Na-jarosite as a trifunctional adsorbent material for addressing water pollution challenges.

Effect of laser power on morphology, microstructure and mechanical properties of CBN abrasive block prepared by two-step laser cladding

The preparation of cubic boron nitride (CBN) grinding tools using laser cladding has the advantages of strong bonding, short time consumption and customizable abrasive arrangement. In this paper, a two-step laser cladding method was used to prepare CBN abrasive blocks with the aim of reducing laser damage to CBN grits during the laser cladding process. The cross-sectional morphology of CBN abrasive blocks under different laser power conditions was characterized, and the relationship among laser power, preparation method, and forming quality of Cu–Sn–Ti/CBN cladding layer was investigated. Then, the microstructure at the Cu–Sn–Ti/CBN interface under different laser power conditions was characterized, and the main phase compositions at the Cu–Sn–Ti/CBN interface were analyzed. Finally, the grinding tests were carried out on CBN abrasive blocks. The results show that as the laser power increases from 250 W to 400 W, the fracture ratio of CBN grits increases dramatically from 4.3 % to 17.3 %. TiN, TiB2, and TiB compounds are all detected at the Cu–Sn–Ti/CBN interface under different laser power conditions. The mass loss of the TC4 wheel caused by the CBN abrasive block initially increases and then decreases as the laser power increases from 250 W to 400 W. The CBN abrasive block has the optimum material removal performance at the laser power of 300 W using two-step laser cladding. The results provide a theoretical basis for the preparation of high-performance CBN grinding tools using laser cladding.

Tailored electrochemical biosensor with poly-diallydimethylammonium chloride-functionalised multiwalled carbon nanotubes/gold nanoparticles/manganese dioxide, and haemoglobin for sensitive hydrogen peroxide detection

A very sensitive electrochemical biosensor, with haemoglobin (Hb) as its basis, has been created to quantify hydrogen peroxide (H2O2), an essential marker in environmental monitoring, food safety, and medical diagnosis. The sensor uses a simple, eco-friendly preparation method. Hb was immobilised on manganese dioxide nanostructure/gold nanoparticles/poly-diallydimethylammonium chloride-functionalised multiwalled carbon nanotubes (PDDA-MWCNT/AuNP/MnO2), characterised using various techniques: amperometry, voltammetry, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Nafion was used as a binder membrane to preserve the biological and electrochemical properties of the protein on the modified electrode. In comparison to earlier research, the novel biosensor had a lower detection limit (1.83 μM) and a limit of quantification (6.11 μM) (S/N = 3) for H2O2. It also exhibited notable reproducibility, long-term stability, and repeatability. It was effectively used to measure the amount of H2O2 in cow milk and orange juice, yielding recoveries in the order of 98.90–99.53 % with RSDs less than 5.0 %, which makes it a promising biosensor for food control.

IrO2 Oxygen Evolution Catalysts Prepared by an Optimized Photodeposition Process on TiO2 Substrates.

Preparing high-performance oxygen evolution reaction (OER) catalysts with low precious metal loadings for water electrolysis applications (e.g., for green hydrogen production) is challenging and requires electrically conductive, high-surface-area, and stable support materials. Combining the properties of stable TiO2 with those of active iridium oxide, we synthesized highly active electrodes for OER in acidic media. TiO2 powders (both commercially available Degussa P-25® and hydrothermally prepared in the laboratory from TiOSO4, either as received/prepared or following ammonolysis to be converted to titania black), were decorated with IrO2 by UV photodeposition from Ir(III) aqueous solutions of varied methanol scavenger concentrations. TEM, EDS, FESEM, XPS, and XRD measurements demonstrate that the optimized version of the photodeposition preparation method (i.e., with no added methanol) leads to direct deposition of well-dispersed IrO2 nanoparticles. The electroactive surface area and electrocatalytic performance towards OER of these catalysts have been evaluated by cyclic voltammetry (CV), Linear Sweep Voltammetry (LSV), and Electrochemical Impedance Spectroscopy (EIS) in 0.1 M HClO4 solutions. All TiO2-based catalysts exhibited better mass-specific (as well as intrinsic) OER activity than commercial unsupported IrO2, with the best of them (IrO2 on Degussa P-25® ΤiO2 and laboratory-made TiO2 black) showing 100 mAmgIr-1 at an overpotential of η = 243 mV. Chronoamperometry (CA) experiments also proved good medium-term stability of the optimum IrO2/TiO2 electrodes during OER.

Tensile and creep resistance improvement of GH4975 alloy for turbine discs via electron beam smelting layer solidification technology

A difficult-to-deform superalloy for turbine disks, which can be used at 850 °C for a long time, was prepared by electron beam melting layer solidification (EBSL) technology with high purity and fine structure. Subsequently, the ingot was processed by hot extrusion technology instead of conventional hot forging, and then the tensile and creep tests were performed after standard heat treatment. The results show that the EBSL alloy exhibits excellent high-temperature strength and creep rupture life compared to the conventional preparation method. Among them, the yield strengths at 20 °C and 850 °C are 8.1 % and 5.2 % higher than those in the literature, and the creep rupture life at 850 °C and 412 MPa is 1.53 times higher than that in the literature. The dislocation-precipitate interaction reveals that dislocation shearing γ′ phase is the major mechanism at 20 °C and 850 °C tensile, and Orowan looping and stacking fault shearing are the decisive mechanism during creep at 850 °C and 412 MPa. MC carbides remaining during solidification are the main source of cracks during deformation by fracture analysis. The reasons for refining the microstructure and improving the purity by electron beam melting are analyzed and explained. We believe this work can provide new ideas and methods for preparing superalloys.