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The paper was handled by our Editor Sophie Primig and is concerned with oxidation that occurs when a composite metal is fusion printed. The cover for the October 2022 issues of the Journal of Materials Science comes from the paper by Wang et al. [[1]], which appeared in issue #29 from August 2022. References 1 Wang R, Gu D, Zhang H, Guo M. High temperature oxidation behavior of laser powder bed fusion printed WC/Inconel 718 composites. [Extracted from the article]

The use of papers in packaging and development of novel technological applications for paper substrates largely depends on the control of the hydrophilic properties of the cellulose fibres and improvement of the water-repellent properties. This review provides an actual summary of available literature on theoretical concepts and practical methods to improve the hydrophobicity of cellulose fibres and paper webs. In the first part, the interaction of water with cellulose fibres and paper webs is described at different levels ranging from the molecular scale over the micro- to macroscale fibre properties towards the interactions with porous substrates. The concepts for hydrophobicity and superhydrophobicity applied to cellulose fibres are reviewed, considering the surface chemistry and topographical features. In the second part, current techniques for hydrophobization based on sizing or direct fibre surface functionalization are described. Besides traditional sizing procedures, novelties in nanoparticle applications as hydrophobic sizing agent are reviewed. Novel trends in physical, chemical and nanotechnological fibre surface modifications or surface coatings are reviewed to turn the wetting properties into the superhydrophobic regime. The main future concern in controlling cellulose wettability lies in the development of sustainable modification techniques based on renewable resources such as biopolymers and green chemistry. [ABSTRACT FROM AUTHOR]

Simulation models are used to emulate real-world phenomena, and errors are inevitable in the numerical computation process. Owing to that, simulation models need to be verified and validated to ensure the models and their implementations are correct. In this paper, V&V has been done for the micro3d discrete dislocation dynamics (DDD) model by comparing simulation results with corresponding theory, including any analytical solutions, other numerical solutions and experimental data. DDD simulations are a powerful simulation methodology that can help researchers better understand the plastic behavior of crystalline materials. In this study, parametric analyses for DDD simulations parameters have been performed. In addition, simulation results are verified and validated. [ABSTRACT FROM AUTHOR]

This three-part paper lends new insight into the interpretation of internal state variable (ISV) theory and fundamentals of the behavior of thermally activated dislocation ensembles. We formally define important physical concepts undergirding ISV theory such as configurational subsystems (e.g., individual grains or phases), constrained local equilibrium, and thermally activated dislocation reactions in the context of crystal plasticity and then implement these concepts within a nonequilibrium statistical thermodynamics framework. The primal importance of the Gibbs free energy barrier to dislocation reactions within each subsystem is emphasized since the enthalpy barriers are affected by local constraint and resulting long-range and short-range athermal internal stresses acting within subsystems. Kinetic and kinematic aspects of individual dislocation reactions are defined. The role of athermal internal stresses in stabilizing the positions of dislocations between barriers is acknowledged by the formal identification of the anelastic deformation, along with its role in contributing to thermal dissipation. Thermal and configurational intrinsic entropy change that contribute to the change of Gibbs free energy as a driving force for reactions are formally introduced in the same way as in first principles methods and are based on probability of pending dislocation reactions at each step. We distinguish equilibrium thermodynamics up to the saddle point of reactions, for which change of both configurational and thermal entropy applies, from post-saddle point extended glide of dislocations, which couples with the thermal bath via dispersive phonon dynamics. We write subsystem and ensemble relations for intrinsic entropy production. The concept of "degree-of-correlation" of the enthalpy barriers of thermally activated dislocation processes is introduced at both the subsystem level and across the overall ensemble of subsystems, based on the ratio of the weighted average enthalpy barrier to the maximum (rate-limiting) enthalpy barrier. It is argued that nonequilibrium trajectories progressively move toward correlated behavior of the ensemble by virtue of internal stress redistribution among interacting subsystems that are favorable and unfavorable to reactions. The degree-of-correlation is a many-body concept involving populations of dislocations within and among various configurational subsystems. [ABSTRACT FROM AUTHOR]

Ni-based wrought superalloys are a type of superalloy produced through casting-forging processes, and usually their high-temperature performance is strongly influenced by microstructure and deformation mechanism. The typical microstructure of Ni-based wrought superalloys after heat treatments comprises equiaxed grains, numerous annealed twins, carbides within the grain interior and/or at grain boundaries, and spherical γ′ precipitates (typically comprises around 20% of their volume). The common deformation mechanisms in Ni-based wrought superalloys mainly include anti-phase boundary formed by paired dislocations shearing γ′ phase, stacking fault formed by single dislocation shearing γ′ phase, dislocation bypassing γ′ phase (precipitation-strengthened) and dislocation entanglement, dislocation networks (solid solution strengthened). In this paper, the microstructure and deformation mechanism of tensile and creep in Ni-based wrought superalloys for Advanced ultra-supercritical (A-USC) power plants are reviewed, for the two prominent areas of current research, Ni–Fe-based wrought superalloys exhibit superior processability and cost-effectiveness compared to Ni–Co-based wrought superalloys, thereby offering a more advantageous solution. [ABSTRACT FROM AUTHOR]

This paper explores the hydrothermal treatment of α-Al2O3 powders to improve the binding in ceramic parts produced via a chemical bonding of ceramic powders combining a phosphate binder and infrared (IR) curing. Alumina powders are pre-treated in hydrothermal conditions with both water and phosphoric acid solution before slurry preparation and infrared irradiation. The effects of hydrothermal treatments on the powder's chemical reactions and the composite's final microstructure are assessed upon IR irradiation. While the water treatment does not induce any chemical changes, the presence of phosphoric acid leads to the appearance of phosphate phases Al(PO3)3 and AlPO4. Hydrothermal treatments in water and in phosphoric acid solution are found to drive faster and more intense phosphate condensation reactions at lower temperatures, with a stronger effect in the presence of H3PO4 (condensation temperature of 150 °C for the H3PO4-hydrothermal treated powder compared to 165 °C for the untreated powder). This improved reactivity of hydrothermal treatment α-Al2O3 powders, especially in the presence of H3PO4, leads to a general decrease of porosity for 3D printed parts compared to untreated alumina (for both top surfaces and cross-sections). While further optimization is needed to reduce the final porosity, it is possible to rapidly print 3D parts using this method, demonstrating a possible pathway to a single-step additive manufacturing (AM) process for ceramics. [ABSTRACT FROM AUTHOR]

Alkali-activated materials (AAM) are crafted to address escalating environmental concerns by utilizing low-carbon industrial waste, thus satisfying the need for innovative alternatives to conventional Portland cement (PC). However, the sustainability profile and cost-effectiveness of AAM depends significantly on the choice of commercial activator, with the high carbon footprint and cost of the activator serving as significant obstacles that limit the utilization of the AAM large-scale construction projects. Some locally available agricultural or industrial alkaline wastes have been researched as activators to activate other materials for AAM preparation, fundamentally eliminating AAM's activator-related drawbacks. All-waste alkali-activated materials (AWAAM) not only solve the issue of alkaline waste disposal but also exhibit satisfactory mechanical properties, along with environmental and economic advantages. This paper provides a comprehensive overview of the current phase of cementitious materials that do not require additional commercial alkali sources and are prepared entirely from waste materials, which is AWAAM. It describes the sources of alkaline wastes, elucidates the principles of synergistic interactions between these materials, explores the enhancement of AWAAM, and evaluates the cost, environmental impacts, and ionic leaching behaviors of AWAAM. Nevertheless, numerous studies have not examined the durability, leaching of hazardous materials, and workability of AWAAM. [ABSTRACT FROM AUTHOR]

The material choice for electrical contacts fundamentally governs the breaking performance, safety, and reliability of electrical switches. In recent years, amid a rapid escalation in infrastructure development, an upsurge in living standards, and advancements in scientific and technological realms, there has been a burgeoning demand for increased load capacity within power distribution systems, thereby imposing novel demands on electrical contact materials. The advent of two-dimensional graphene, with its exceptional electrical conductivity, thermal conductivity, and mechanical attributes, has piqued the interest of researchers in the electrical contact field. This has spurred further research and development into innovative graphene-enhanced electrical contact materials. This paper presents a comprehensive review of the progression made in graphene-enhanced silver-based electrical contact materials over the recent years. It particularly delves into the application of graphene in silver-based contact substances, encompassing the most recent developments in graphene-enhanced contacts, the underlying principles and processes governing arc generation and erosion, the arc-resistant mechanisms inherent to graphene-enhanced contact materials, and provides a forward-looking perspective on the potential future of graphene-based contact materials. [ABSTRACT FROM AUTHOR]

Highly integrated and high-power devices place higher demands on the heat dissipation capability of heat sink components, and graphene meets the heat dissipation requirements due to its extremely high thermal conductivity of 5300 Wm−1 K−1 and good mechanical properties. Graphene by redox is one of the most promising methods for large-scale preparation of graphene; however, the quality of graphene prepared by different reduction processes varies. Herein, this paper presents a fast and efficient reduction process. Benzene was added as a reduction aid to increase the temperature from room to 2000 °C in 30 s and complete the reduction process. By this method, we obtained graphene with low defects and high thermal conductivity. The reduction process restored the lattice destroyed by the oxidation process, and the repaired material showed a higher crystallinity with a measured ID/IG of 0.18 (Ph-rGO-0, 0.58) and in-plane thermal conductivity of 510 ± 10 Wm−1 K−1. The in-plane thermal conductivity was increased by 262 Wm−1 K−1 compared with the film without benzene addition (Ph-rGO-0), which showed better homogeneous temperature performance and heat dissipation performance in practical applications. These results show the great potential for the application of graphene films prepared by this method in the field of heat dissipation materials. [ABSTRACT FROM AUTHOR]

Y2O3 materials have been widely applicated in high temperature industry owing to its high temperature stability. However, the poor sintering behavior and thermal shock resistance limited its application. The existing studies were focused on its sintering properties, yet the increase in densification of Y2O3 materials could weaken its thermal shock resistance. Y2O3 materials with smaller closed pores were fabricated by the decomposition of Al(OH)3 and the effect of Al(OH)3 on the microstructure, mechanical properties and thermal properties of Y2O3 materials were investigated in this paper. We concluded that the migration of grain boundaries was accelerated due to the ionic radii difference and the diffusion coefficient between Y3+ and Al3+, and the diffusion coefficient of Y3+ was relatively weak while the diffusion of Al3+ was mainly dominated. The Al2O3 produced by decomposition of Al(OH)3 was active, which promoted the sintering of Y2O3 materials. Meanwhile, the porosity and pore structure of Y2O3 materials were affected by the decomposition of Al(OH)3, and the appropriate pores improved the thermal shock resistance by absorbing thermal stresses. Furthermore, it indicated that adding Al(OH)3 into Y2O3 materials had a powerful influence in balancing its sintering properties and thermal shock resistance. The sample with 3 wt% Al(OH)3 exhibited the better performance in this study, with the relative density of 93.2% and the thermal shock stability factor parameter Rst of 1.74 W m1/2. [ABSTRACT FROM AUTHOR]

In the recent years, molybdenum disulfide (MoS2) has been widely used in various optical applications. MoS2 has decent optical band gap and can be used as photocatalyst for hydrogen production applications. In this paper, we reported the synthesis of flower-like nickel (Ni)-doped MoS2. The as-prepared Ni@MoS2 has optical band gap of 1.71 eV which was lower than that of the pristine MoS2 (1.90 eV). Thus, Ni@MoS2 was further used as photocatalyst for hydrogen evolution. The effect of different dose (5, 10, 15, 20 and 25 mg) of the photocatalyst (Ni@MoS2) was also examined. The photocatalytic investigations exhibited the generation of good hydrogen production amount (2021.5 µmol g−1) with reasonable hydrogen generation rate of 404.3 µmol g−1 h−1 using 25 mg Ni@MoS2. These findings suggested that doping may significantly improve the photocatalytic hydrogen production. The proposed Ni@MoS2 also presented good stability and reusability for hydrogen production. [ABSTRACT FROM AUTHOR]

The demolding process of electroforming technology in fabricating microstructured optical-functional thin films produces the problem of excessive bonding between the metal substrate and the metal replica, which triggers the deformation of the microstructure and the reduction of precision, and the deposition of Cr–O–C discrete nuclei at the interface can play a good role in assisting the demolding effect. In this paper, the tensile deformation of polycrystalline Cu/Ni and Cu/Cr–O–C/Ni composites is investigated using molecular dynamics methods. The results show that the Cu/Ni model produces a large number of HCP structures during stretching, with holes at the interface and a large number of Cu atoms transferring to the Ni layer. The addition of the Cr–O–C layer reduces the yield strength of the Cu/Cr–O–C/Ni model by 26.41%, and at the same time, the dislocation proliferation at the interface is reduced, and the fracture is at the centralized interface, and the fracture time is reduced by 90.8%. The higher number of Cr–O–C atoms at the interface decreases the transfer of Cu atoms to the Ni layer. The results provide a possible explanation for the Cr–O–C layer-assisted precision electrodeposition debonding. [ABSTRACT FROM AUTHOR]

This paper outlines a new approach to designing tunable electromagnetic (EM) graphene-based meta-surfaces using convolutional neural networks (CNNs). EM meta-surfaces have previously been used to manipulate EM waves by adjusting the local phase of subwavelength elements within the wavelength scale, resulting in a variety of intriguing devices. However, the majority of these devices have only been capable of performing a single function, making it difficult to achieve multiple functionalities in a single design. Graphene, as an active material, offers unique properties, such as tunability, making it an excellent candidate for achieving tunable meta-surfaces. The proposed procedure involves using two CNNs to design the passive structure of the graphene meta-surfaces and predict the chemical potentials required for tunable responses. The CNNs are trained using transfer learning, which significantly reduced the time required to collect the training dataset. The proposed inverse design methodology demonstrates excellent performance in designing reconfigurable EM meta-surfaces, which can be tuned to produce multiple functions, making it highly valuable for various applications. The results indicate that the proposed approach is efficient and accurate and provides a promising method for designing reconfigurable intelligent surfaces for future wireless communication systems. [ABSTRACT FROM AUTHOR]

To obtain the VO2 film/CVD diamond-coated tools, the deposition process of CVD diamond coating on the VO2 film surface is investigated in this paper. Firstly, the effect of carbonization treatment on VO2 film is studied. Then, the deposition process of CVD diamond coating on the VO2 film is studied. Finally, it is studied that the change law of the VO2 film/CVD diamond coating system stresses under thermal loading. Results indicate that the CVD diamond coating can be grown on the VO2 film after carbonization and diamond seed crystal treatment. The V6C5 is the most stable material after the carbonization of the VO2 film, and it is used to connect diamond coating and VO2 film. The VO2 film/CVD diamond coating system stress undergoes a sudden change under thermal loading. After the sudden change of stress, the VO2 film/CVD diamond coating system stress is only half of the CVD diamond coating stress. The adhesion of CVD diamond coating is more than 100 N. This study can provide a new idea for the deposition of CVD diamond-coated cutting tools with high bonding performance. [ABSTRACT FROM AUTHOR]

High frequency fatigue behavior of near surface of turbine disk are critical for its application and operation. High frequency indentation fatigue tests of GH4169 alloy under different load amplitudes, frequencies and mean loads at small length scale were conducted, and the dependence of load amplitude, load frequency and mean load on high frequency indentation fatigue property of GH4169 alloy are discussed in this paper. Depth amplitude (ha), mean depth (hm) and depth propagation rate (dh/dN) were employed as evaluation indicators of the indentation behavior. Results show that depth amplitude is only relevant with load amplitude, while mean depth is related to all the adopted influencing factors, ranked in an ascending order as load amplitude, mean load and frequency with a ranking relation of nm1=1.4 < nm2=1.71 < nm3=2.02. Furthermore, a modified Paris law was utilized to reveal the fatigue mechanism, and found the fatigue mechanism is dominated by intrinsic mechanism under the influence of mean load and load amplitude, while for the influence of frequency, the fatigue mechanism is governed by extrinsic mechanisms. Combined with SEM results and three-dimensional morphology analysis, it can be deduced that dislocation movement mode in high frequency indentation fatigue is dislocation slip. [ABSTRACT FROM AUTHOR]

The wettability of the membrane surface is very important for the separation of oil-in-water emulsion. In this paper, the hydrophilic NH2-CAU-1 was added to the membrane surface by interfacial polymerization, which greatly improved the separation efficiency of oil-in-water emulsion. The effect of the amount of NH2-CAU-1 on the separation efficiency of TFN membrane was studied, and it was determined that TFN-1 membrane had ultra-high separation efficiency of oil-in-water emulsion (> 97.60%). TFN-1 membrane has a high underwater oil contact angle (higher than 139.53°), resulting in excellent oil adhesion resistance on the membrane surface. The universality and cycling performance of TFN-1 membrane were tested, and UWOCA had good stability under strong acid, strong base and different NaCl concentrations, and the separation efficiency did not change significantly after 8 cycles. The results show that TFN-1 membrane has excellent performance in separating oil-in-water emulsions and has broad application prospects in separating oil-in-water emulsions stabilized by surfactants. [ABSTRACT FROM AUTHOR]

Characteristics of dislocations induced by Vickers indentation in hydride vapor phase epitaxy GaN were investigated. Dislocations in a rosette pattern have a 11 2 ¯ 3 / 1 1 ¯ 00 slip system and are mobile under both electron beam and multiphoton excitation. They act as nonradiative recombination sites in the range of 370–560 nm. Dislocations in a flower pattern have a 11 2 ¯ 0 / 0001 slip system and are immobile under excitation. The straight part and loop part of dislocations in a flower pattern are radiative at 440 nm and nonradiative in the range of 370–560 nm, respectively. Dislocations in a triangular area are radiative at 386 nm. The origin of the light emitting property of the straight part in a flower pattern is discussed as the transition between partial dislocations dissociated from an a-type dislocation on (0001). Recalculated dislocation pattern size ratios are well matched with experimentally estimated ones by replacing the dislocation type in a rosette pattern described in the earlier literatures (a-type) with estimated dislocation types in this paper (c + a-type). [ABSTRACT FROM AUTHOR]

The introduction of nanotechnology in the food industry has created several opportunities for this sector. Several recent advancements in food packaging use nanotechnology to enhance the function and quality of the packaging materials. This review focuses on how various nanomaterials used in different packaging materials help in maintaining the quality and shelf life of the food product. Several applications of nanomaterials in food packaging such as the use of silver nanoparticles as powerful antibacterial agents, polymer/clay nanocomposites as high barrier packaging materials, and nanosensors were mentioned here. The advances in food nanopackaging, including improved, active, smart, and bio-based packaging, were also discussed. The bio-based packaging offers a substitute for the most widely used non-degradable polymer substances. This review paper aims to highlight some of the most recent technological developments with the use of nanotechnology in the food industry and to indicate some of the many potential future research directions. [ABSTRACT FROM AUTHOR]

This research paper presents a technology for preparing hydrogels based exclusively on natural materials (alginate, carboxymethylcellulose and starch) as carriers of micronutrients (Cu, Mn and Zn). Experiments were performed to select the hydrogel matrix components, including a comparison of the viscosity and density of sodium alginates purchased from different manufacturers, as well as the effect of additives (carboxymethylcellulose and starch) on the swelling properties and strength of the structures. Finally, a solution containing 2 wt% alginate, 2 wt% carboxymethylcellulose and 10 wt% starch was used to prepare reproducible spherical hydrogels. The influence of hydrogel preparation methods on their sorption capacity and strength (either direct dropping into micronutrient solution or two-step, i.e., dropping into calcium chloride and later sorption in micronutrient solution) was also explored. The study revealed that the enrichment of hydrogels with micronutrients by the two-step method is slower, but the structures have better mechanical strength (Young's modulus more than 4 times higher) than those enriched by the one-step method. A series of analyses (FTIR, TGA, XRD and TEM) showed that obtained hydrogels have a semicrystalline structure, are thermally stable and mainly involve carboxylic acid groups in the enrichment process. The effectiveness of the designed hydrogel matrix for the slowed release of micronutrients has been preliminarily proven in winter wheat germination tests. The best results (12.2 cm stem length and 47.9 cm roots) were obtained for the group, where hydrogels were applied at a dose equivalent to 50% of the wheat's Cu, Mn and Zn requirements. [ABSTRACT FROM AUTHOR]

Calcium cobaltate (Ca3Co4O9) is an excellent thermoelectric (TE) material that can realize the mutual conversion between thermal and electrical energy based on the Seebeck effect. Compared with other ceramic TE materials, Ca3Co4O9 has the advantages of good oxidation resistance and high-temperature stability, but its electrical conductivity is low, making its TE properties insufficient. Thus, the figure of merit (ZT) of Ca3Co4O9 materials cannot meet the actual production needs, so it is necessary to modify the Ca3Co4O9 to improve its TE properties. By doping with other elements, the carrier concentration in the Ca3Co4O9 system will increase, and the phonon scattering by impurity atoms will occur, whereas the scattering of electron is rather weak. Thus, the electrical conductivity of the material increases and the thermal conductivity decreases. Therefore, the TE properties of the Ca3Co4O9 material will be improved. This paper summarizes the methods of doping with other elements to improve the TE properties of Ca3Co4O9 materials in recent years, mainly including Ca site doping, Co site doping, and Ca and Co site double doping with various elements, including alkali (earth) metals, transition metals, rare earth metals, and even main group metals and non-metals. Furthermore, the current problems and development trends of the doping modification of Ca3Co4O9 materials are discussed to provide a theoretical basis for the further development and utilization of Ca3Co4O9 TE materials. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced thermoplastic composites (CFRTPs) are widely used in industrial manufacturing due to their excellent mechanical properties, and the joining of lightweight metal/CFRTP hybrid structure has gained more attention. Ultrasonic welding is a promising method for achieving metal/CFRTP dissimilar joining. In this study, 6061 aluminum alloy and carbon fiber-reinforced polyamide-66 (CF/PA66) were ultrasonically welded by preparing a PA6 coating on the surface of aluminum sheet as an interlayer. This paper investigates the effects of welding parameters on the joint mechanical property. Optimized process parameters (welding force 600 N, amplitude 60% and welding time 0.6 s) are determined by experiments. The effects of the thickness and crystallinity of the PA6 coating on the joint strength are investigated. The results show that there exists an optimal coating thickness that maximizes the joint strength. Low crystallinity of the coating contributes to high joint strength. Mixed failure mode (adhesive failure, substrate failure and cohesive failure) is observed based on the analysis on the fracture surface. [ABSTRACT FROM AUTHOR]

Self-powered photodiodes based on the photovoltaic effect have garnered substantial attention, addressing the pressing need for a new generation of optoelectronic nanodevices. However, conventional junction-type self-powered photodetectors exhibit performance limitations. In this paper, we propose a high-speed phototransistor incorporating a dual van der Waals heterostructure (vdWH) of ReS2/WSe2/Te. The device demonstrates a low dark current level (10−14 A). In self-powered mode, the device exhibits exceptional optical response at 785 nm laser (10 µW), achieving a responsivity of 13.98 mA·W−1, a detectivity of 1.65 × 1011 Jones, and an on/off ratio of up to 106. Additionally, the device displays a fast rise/fall time of 7.2/7.14 µs at 532 nm laser (10 µW). Energy band analysis and carrier transfer studies reveal that the floating heterojunction at the bottom of the dual vdWH effectively increases the photogenerated carriers in the top vdWH layer as well as reduces their recombination. This photodetector design provides a practical pathway toward the development of high-performance phototransistors. [ABSTRACT FROM AUTHOR]

Composites are popular in construction engineering due to their low water absorption, good chemical and corrosion resistance, lightweight, high specific strength, high specific modulus, and low thermal conductivity. The flame retardancy (FR) of composite materials has increasingly become the focus of attention in the field of construction engineering. With growing awareness of personal and property safety, a wide range of flame-retardant composites has been developed over the years through research and development. The FR of an unmodified polymer composite is not optimal, and therefore, many innovative methods for making more advanced flame-retardant materials have been developed. The aim of this review is to provide detailed literature on flame-retardant composites. The structure of this paper consists of evolution of flame-retardant materials, their manufacturing techniques, flame-retardant composites, their properties and characterization, applications, and challenges related to of FR composites. The primary focus of this review is to analyze the mechanism of fire retardancy and to summarize the preparation of flame-retardant polymer materials by adding various flame-retardant agents. [ABSTRACT FROM AUTHOR]

This paper presents experimental ductile fracture data for 2139-T8 aluminum alloy under various stress states for the ultimate purpose of probing the fracture envelope as a function of stress triaxiality and normalized Lode angle. A new ductile fracture model is also proposed and validated by experimental data, along with the evaluation of existing ductile fracture models. The data extracted from published literature on 2024-T351 aluminum alloy was also used as an additional experimental data set for validation. An extensive experimental program was implemented to produce data in a wide range of stress states, including tensile tests (with round smooth, round notched, and plate specimens), torsion, compression (with round smooth and round notched specimens), and shear-compression experiments (two different sizes). The combined effects of stress triaxiality and normalized Lode angle were used to define a 3D fracture envelope for fracture strain. A parallel finite element simulation (fine-tuned by the experimental results) has been performed for each experiment to evaluate the evolution of stress triaxiality and normalized Lode angle in the critical section of the specimens with complex geometries. Finally, these results were used to develop two fracture models whose predictions were compared with some of the existing models. [ABSTRACT FROM AUTHOR]

We disclose a method for the wet chemical etching of silicon (001) surface with a conical texture. This method involves a single-step etching process without additional surface treatments. The conical texture is compared to the pyramidal texture resulted from conventional chemical processes. Scanning electron microscopy reveals smaller dimensions of the surface cones as compared to the pyramids. Reflectance measurements show a slight decrease in the reflectivity for the samples with the conical texture as compared to the pyramidal texture. X-ray diffraction was performed to investigate the state of strain in the textured samples. In regard to the solar cell fabrication, we discuss in the paper the advantages of the conical texture as compared to the pyramid texture. [ABSTRACT FROM AUTHOR]

Aluminum hydride (AlH3), as a potential new metal fuel, has attracted extensive attention in the field of hydrogen storage materials, propellants and energetic materials due to its excellent properties. In this paper, a new organic liquid phase reduction method was used to prepare AlH3, and the microstructure and composition of the prepared samples were characterized by SEM–EDS, XRD, FT-IR, XPS, etc. The main crystal phase of the prepared AlH3 was α-AlH3, with high quality and no other impurities. The thermal decomposition behavior and non-isothermal reaction kinetics of AlH3 were investigated by TG-DSC. The results show that there are three exothermic stages in the heating process of AlH3: dehydrogenation of AlH3, first oxidation of Al, and second oxidation of Al. The activation energy of the dehydrogenation of AlH3 is 77.8675 kJ/mol (Kissinger method) and 81.4862 kJ/mol (Ozawa method), respectively. The morphology evolution of AlH3 particles during the heating process (300–3000 K) was simulated using a reaction kinetics method based on the ReaxFF force field. The response behavior of AlH3 in the instantaneous high-temperature detonation environment was investigated using the high-energy laser-induced shock wave technique. Under the impact of a high-energy laser (1006 mJ), the AlH3 sample undergoes an ultra-fast reaction and generates a large amount of plasma. The expansion of the plasma pushes the surrounding air to form a supersonic shock wave and propagates forward. The shock wave propagation velocity of AlH3 is 690.99 m/s in the range of 2.1–12.35 μs, and the higher the laser energy, the faster the shock wave propagation velocity. This study provides the basis for the application of AlH3. [ABSTRACT FROM AUTHOR]

In this study, an efficient visible light responsive MIL-125(Ti)/ZnIn2S4 hybrid structure (MIL-1.2/ZIS) was synthesized through two-step method with improved photocatalytic H2-evolution performance. The MIL-1.2/ZIS nanocomposites could retained the characteristic features including the highly surface area of metal organic frameworks and the hierarchical sheet-like structure of ZnIn2S4. The optimal sample could exhibit the H2 generation rate of 873.4 μmol g−1·h−1, and the improved photocatalytic activity could be ascribed to the well-matched band structure and the formation of hybrid interfaces, which could lead to the effective charge transfer and separation of photo-excited electron–hole pairs. We hope this paper could broad the potential utilization of MOF-based nanocomposites in photocatalytic energy conversion fields. [ABSTRACT FROM AUTHOR]

Tissue engineering faces an intriguing challenge in creating biomaterials for cartilage repair. Within the category of biopolymeric scaffolds, hydrogels made from polysaccharides are particularly suitable for regenerating cartilage tissue. In this paper, a new formulation of biocompatible alginate-based hydrogel for joint cartilage regeneration was investigated. An alginate-dendrimer hydrogel obtained by covalently grafting alginate with polyamidoamine generation 5 dendrimer. 58S bioactive glass was synthesized through sol–gel procedures and was added to the hydrogel before cross-linking. The obtained hydrogel is an innovative system with sustained drug-releasing properties and improved mechanical behavior in comparison to the alginate matrix. For instance, the tensile and compressive modulus of the fabricated composite hydrogel increased from 0.035 to 0.072 MPa and 0.17 to 0.40 MPa respectively. Whereas the degradation ratio decreased from 0.26 to 0.09% by the addition of polyamidoamine and bioactive glass. The developed hydrogel also showed better properties in in-vitro studies such as swelling and degradation. MTT assay showed no toxicity and revealed the biocompatibility of prepared hydrogel. The MTT test, also performed better adhesion of cells by the addition of bioactive glass powder. The composite hydrogel loaded with tetracycline hydrochloride showed more sustained drug-release behavior and excellent antibacterial properties compared to bear alginate hydrogel. Therefore, the Alginate/polyamidoamine/bioactive glass hydrogel can couple the well-known bioactive properties of 58S bioactive glass with good biocompatibility of alginate-dendrimer hydrogels, opening new approaches in the field of tissue engineering. [ABSTRACT FROM AUTHOR]

3D bioprinting of biomimetic tissue is critical for engineering artificial soft tissues and organs. However, the lack of simultaneously printed multiscale blood vessels within the scaffolds and the cell damage in the bioprinting nozzle decreased viability and limited the potential of printed tissues. This paper adopted 3D-printed sacrificial molds for the fabrication of hydrogel scaffolds with internal channels. The process fills slow-gelling sodium alginate into 3D-printed water-soluble PVA molds to create channels within the hydrogel. The results showed that hydrogel and crosslinker concentration have significant effects on gelation time, channel width, and scaffold compressive strength. Simulation results showed that both higher hydrogel and crosslinker concentrations contribute to higher residual stress within the scaffolds. This novel scaffold fabrication process has the potential for the vascularization of various organ and tissue models for tissue engineering applications. [ABSTRACT FROM AUTHOR]

The Journal of Materials Science has a strong focus on publishing papers related to metals. The journal's editors have extensive experience and expertise in the field of metals, with some of them having authored highly cited publications. One of the editors, Megumi Kawasaki, is a renowned researcher in the field of bulk nanostructured materials and holds positions at Oregon State University and Osaka Metropolitan University. Another editor, Philip Nash, is a Professor Emeritus at the Illinois Institute of Technology and has made significant contributions to the field of physical and process metallurgy. Sophie Primig, a professor at UNSW Sydney, specializes in structure-property relationships in structural metallic materials, particularly aerospace alloys. Zhao Shen, a professor at Shanghai Jiao Tong University, focuses on the design of corrosion-resistant alloys and coatings. Naiqin Zhao, a professor at Tianjin University, has expertise in the fabrication and characterization of alloys and composites. The Journal of Materials Science provides a platform for researchers in the field of metals to share their findings and contribute to the advancement of the field. [Extracted from the article]

Lattice rotation mechanism plays an important role in the plastic deformation and the microstructure evolution of nanocrystalline metals. It assists the grain growth and the polycrystal texture formation. In this paper, the lattice rotation of quasi-3D Ni samples under uniaxial tension is investigated by molecular dynamics simulations. For this purpose, the bi-crystal and polycrystal models are created and systematic molecular dynamics simulations are carried out to mimic the uniaxial tensile tests. Based on the Schmid shear slip theory, the relationship between the Schmid factor of different slip systems and the grain orientation angle is established. It is found that the starting slip system angle is a fixed angle with the initial orientation angle of grain. Moreover, the cumulative rotation of the grain slip system and the initial angle of the slip system are statistically analyzed. It is found that a larger deflection angle of the slip system leads to a larger lattice rotation. [ABSTRACT FROM AUTHOR]

Thermoelectric materials have advanced significantly in terms of machinery, manufacturing technique and technology over the last 10 years. However, conventional processing methods still necessitate a multitude of processing steps, thereby yielding material loss and imposing a substantial surge in manufacturing expenditures, which significantly obstructs the advancement of intricate and scalable thermoelectric devices. Additive manufacturing technology (AM) is an emerging and innovative technology offering rapid manufacturing cycles and efficient production of intricate geometries. While additive manufacturing has been utilized for fabricating thermoelectric materials, its application in the manufacturing of thermoelectric devices remains somewhat restricted. Although there have been some research reviews of AM thermoelectric materials in recent years, they are basically focused on the development and achievements of AM thermoelectric materials. This paper presents a comprehensive review of the research advancements of additive manufacturing technology in the fabrication of thermoelectric materials. It discusses the impacts of various processing parameters on the quality of the fabricated thermoelectric materials and their resulting thermoelectric properties. Simultaneously, each additive manufacturing technology for the fabrication of thermoelectric devices, as well as future research objectives and problems, is thoroughly examined. [ABSTRACT FROM AUTHOR]

The remediation of water from organic pollutants, such as dyes and related compounds and the reuse of discarded glasses, represents fundamental challenges in highly industrialized countries. Porous glass microspheres have been proposed as efficient adsorbents in wastewater treatment, but their real application is problematic, especially from the perspective of their reuse and recycling. For the first time, the present paper describes the process of preparation and use of highly porous bodies with a specific surface area of nearly 20 m2/g fabricated from alkali activated glass microspheres and applicable for the removal of methylene blue as a model organic dye from wastewater. Alkali activation is applied both as an intermediate step (using 9 M KOH) for the conversion of waste glass into porous microspheres by flame spheroidization process, and as a final step (using 2.5 M NaOH), facilitating low temperature consolidation of the microspheres, and their transformation into porous structures. The experimental adsorption capacity of porous glass microspheres pellet was 122 mg/g. The high correlation coefficient indicates the applicability of Langmuir isotherm adsorption model. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) is an additive manufacturing method that generates much residual tensile stress during processing. Laser shock forging (LSF) is a surface treatment technology that can reduce residual stress on the metallic surface. At present, there are no reports on in situ LSF (ILSF) during the SLM process. The effect of ILSF on the residual stress field induced by SLM was systemically investigated using the finite element method (FEM), and the parameters were optimized. Optimized finite element simulation calculated the stress field after the ILSF impact. The results show that the SLM deposition layers have significant residual tensile stress, with a maximum range of 152 μm and extremely inhomogeneous distribution. LSF can convert SLM-induced tensile stress into compressive stress. The two most important ILSF parameters are peak pressure (Pmax) and initial temperature (Ti). The range and magnitude of the residual compressive stress field increases with Pmax and decreases with the initial temperature. The sufficiently large LSF Pmax is essential in the LSF process. When Pmax is large enough, the effect of the multiple shots on the magnitude and depth of compressive stress is insignificant. The high Ti will significantly reduce the effect of ILSF, even if residual compressive stress is not obtained. Ti influences the stress field through an inhomogeneous temperature gradient. The temperature gradient is strongly correlated with the residual stress variation, and the fitted equation shows that the stress field is a power function of the temperature gradient. This paper provides an essential guide to improving the residual stress field in additive manufacturing processes. [ABSTRACT FROM AUTHOR]

The field of tissue engineering involves various methodologies employed to improve or replace biological tissues with extracellular matrices (ECMs). Significant progress has been made, particularly in the fabrication of three-dimensional (3D) scaffolds for replacing damaged tissues or organs. The current review broadly focuses on the various research works carried out involving the use of biomaterials (biopolymers, bio-ceramics and dopants) in this area. A detailed discussion on several scaffold-making modern technologies has also been provided, along with a demonstration of different characterization techniques. Though a number of review papers have been published on biomaterials and fabrication techniques, a very small number focuses on the clinical trials carried out and the commercialization of scaffolds in the biomedical field. Thus, a critical analysis and detailed discussion of some of the clinical trials, market growth, and future demands have been presented in this paper. [ABSTRACT FROM AUTHOR]

Proton exchange membrane fuel cells (PEMFCs) require efficient water management. Microporous layers (MPLs) are crucial to solve this problem due to their positive effects on the two-phase mass transfer process. The performance of MPLs is mainly determined by the properties of the materials used for their construction as well as other basic transport properties, including morphology, porous structure, wettability, and electrical resistivity. In this study, graphite and reduced graphene oxide (rGO) were used as the main components to fabricate MPLs for use in PEMFCs because they are highly conductive and thermally efficient. Single-layer MPLs are prepared by compressing MPL powders with different proportions of ingredients. In contrast, two-layer gas diffusion layers were fabricated by applying MPL pastes to a benchmark Toray carbon paper using a screen-printing process. FTIR and XRD analysis of main components and some samples are performed to investigated functional groups and the nature of MPLs' surface, respectively. An analysis of the effects of graphite, rGO, and hydrophobic agents' constituents on the physical properties (electrical resistivity, contact angle, roughness, porosity, and permeability) of the fabricated MPL or MPL-coated carbon papers by screen-printing method has been performed. Also, the effect of different coating methods (screen-printing and spraying) on different properties of graphite-based and rGO-based MPLs has been investigated. The results show that composites based on rGO have higher electrical resistivity than that of graphite-based MPLs, but lower roughness. However, MPLs based on rGO exhibit better contact angle, higher porosity, and improved gas permeability. Moreover, as expected, the contact angle and electrical resistivity increase, while the porosity and permeability decrease when the hydrophobic agents (polytetrafluoroethylene, and polyvinylidene difluoride) which are also used as binders, are increased. On the other hand, screen printed graphite-based MPL has lower electrical resistivity, while screen printed rGO-based MPL has higher porosity percentage, roughness, and permeability than the sprayed one. [ABSTRACT FROM AUTHOR]

The small punch (SP) test has been widely used in applications where conventional mechanical tests cannot be performed; this paper predicts the material strength from the SP test results by empirical correlations method. The yield strength (YS) and ultimate tensile strength (UTS) models serve to associate the load–displacement (LD) curves of SP tests with the stress–strain data of uniaxial tensile tests, and then, the feasibility of these models at different temperatures is investigated. Using the Pearson's correlation coefficient (PCC) method, the ideal strength equations are accessed from past studies for the cast superalloys, including ZG15Cr2Mo1, P91, 316H, and Hastelloy X, whereas the validation results of the additively manufactured (AM) GH4169 alloy are not satisfactory. As a result, considering the unique manufacturing process of AM GH4169, this paper develops a YS model with correlation coefficients higher than 90% between the calculated and actual values and proposes a UTS formula with estimation errors less than 3.5%. Furthermore, with the purpose of superior strength prediction results, the discussion of the SP test velocity reveals that 0.50 mm min−1 had wide adaptability to various strength models and operating temperatures. [ABSTRACT FROM AUTHOR]

Phagraphene is a newly proposed two-dimensional allotrope of carbon. Its structure resembles that of a defective graphene sheet. The unit cell structure of phagraphene consists of a 5–6–7 ring sequence due to which it possesses lower energy than most carbon allotropes. Phagraphene has properties, namely thermal conductivity of 218 ± 20 W/mK and 285 ± 29 W/mK, along armchair and zigzag directions, respectively, a tensile strength of 85 ± 2 GPa, the elastic modulus of 870 ± 15 GPa along armchair and 800 ± 14 GPa along zigzag direction, and fracture strain of the same order as that of pristine graphene. Density functional theory and molecular dynamics simulations have proved the unique electronic properties of phagraphene, namely direction-dependent Dirac cones, tunable Fermi velocities, quasi-direct band gap, to be comparable with pristine graphene. Based on molecular dynamics and density functional theory investigations, phagraphene is capable of being used in Li-based batteries and thermoelectric devices as anode material due to its good adsorption properties and remarkably good doping characteristics. Such characteristics can lead to a future trend of analyzing such allotropes because phagraphene can provide potential applications in atmospheric pollutant-detecting and drug-carrying properties in ailments like cancer. This paper is a nascent one discussing all the previous works on molecular dynamics simulations of phagraphene and tries to serve as the leading one for researchers interested in this field. This paper summarizes the mechanical and thermal properties of phagraphene estimated using molecular dynamics simulations as studied in previous works. The study shows that molecular dynamics has a good application in studying such a novel carbon allotrope. The discussions made in this paper thematize phagraphene's properties as a next-generation material and can help the researchers in a qualitative overview. [ABSTRACT FROM AUTHOR]

This study clarifies the absorption behavior of micro-droplets of water on treated paper to support the design of functional microstructures, such as electronics and micro-fluid channels, on paper. The period of time between when a micro-droplet of water ejected from an ink-jet head lands on the paper's surface and its complete disappearance by absorption was defined as the micro-sizing degree (MSD), and an MSD measurement method was established. The MSD was evaluated using microscopic high-speed video images of the side view recorded every millisecond. Several grades of commercially available ink-jet paper media and laboratory sheets having different levels of water repellency prepared from a pulp and a sizing agent were examined. The MSD of commercial ink-jet papers, which are known to absorb water very quickly, was 3-6 ms. Weakly sized laboratory sheets exhibited a lower MSD of 2-3 ms. The absorption behavior was analyzed in terms of the capillary pressure with and without the Laplace pressure; the theoretical and experimental results agreed moderately well. The results indicated that the Laplace pressure cannot be neglected in the analysis. The MSD of a wet surface where a preceding micro-droplet had already landed was higher than that on a dry or partially wet surface, presumably because water remains inside pores for an unexpectedly long time. [ABSTRACT FROM AUTHOR]

We present theory for the shrinkage on drying of the cross-sectional area of cellulosic fibres and show that this depends on their initial moisture content only. For the linear shrinkage of cross-sectional dimensions, an additional parameter is required, which we estimate from comparison of the theory with experimental data from the literature. We proceed to combine our model of fibre shrinkage with probabilistic theory for fibre contacts in random fibrous networks to obtain a model for the unrestrained shrinkage of isotropic paper sheets. The expression obtained depends only on the moisture content of fibres and the extent of inter-fibre contact and exhibits good agreement with experimental data for laboratory-formed paper sheets. The results have relevance to the commercial manufacture of paper and potential for application to the study of cellulose nano-composites. [ABSTRACT FROM AUTHOR]

Paper–paraffin composites were prepared by an interfacial polymerisation reaction on the paper surface and its function of thermal energy storage was studied. Filter paper impregnated with O/W emulsion, which was composed of ethylenediamine, NaOH and paraffin microcapsules prepared by methyl methacrylate polymer (PMMA), was left in a beaker containing a cyclohexane solution of terephthaloyl chloride. The paraffin could fix on the treated paper surface and the encapsulation of the paraffin before the interfacial polymerisation reaction on the paper surface was effective in the preparation of paper with the function of heat storage. [ABSTRACT FROM AUTHOR]

In this study, nylon microcapsules were prepared on a paper surface using an interfacial polymerization technique for the preparation of smart paper. Filter paper impregnated with ethylenediamine solution and NaOH solution was left in a beaker containing cyclohexane or chloroform. Subsequently, the organic solvent terephthaloyl chloride was added to the beaker and interfacial polymerization occurred on the paper surface. When cyclohexane was used as the organic solvent, formation of nylon microcapsules on the paper surface was confirmed. Fixation of nylon microcapsules on the paper surface was successfully performed using interfacial polymerization. On the other hand, it was not possible to form nylon microcapsules on the paper surface when interfacial polymerization with chloroform was carried out. These results are due to differences in the spreading coefficient of the organic solvent on the ethylenediamine solution adsorbed on the paper surface. [ABSTRACT FROM AUTHOR]

A facile and cost-effective modified sol–gel synthesis is employed to synthesize flexible silica-cellulose hybrid aerogels (SCHA) using recycled cellulose fibers (RCF). The effect of cellulose fiber concentrations and ambient temperature conditions on the thermal, acoustic, and oil absorption characteristics was quantified comprehensively. The experiments were conducted by considering the range of weight fractions from 1–4 wt.% from waste tissue paper with a cross-linker and tetraethylorthosilicate (TEOS) as silica precursors. The SCHA aerogels were modified by a silylating agent with surface hydroxyl groups to achieve superhydrophobic behavior with a water contact angle (WCA) as high as 168°. The synthesized aerogels were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscope (SEM), and Brunauer-Emmett-Test (BET) to identify the physical morphology. An excellent oil absorption capacity of 24.8 g.g−1 was also noticed with 4 wt.% of cellulose concentration in hybrid aerogel retained up to 5 cycles with an absorption capacity of 6.4 g.g−1. The average thermal conductivity of hybrid aerogels was estimated in the range of 0.038–0.032 W/m K. Slight enhancement in the thermal conductivity is noted with the increase in wt.% of cellulose to the silica aerogel. However, about 40–50 °C improvement in thermal degradability (as concluded from Thermogravimetric Analysis) with a minimum weight loss was observed in hybrid aerogel over cellulose aerogel. A comparatively high sound absorption coefficient of 0.453–0.628 at low frequency (1500 Hz) and 0.86–0.94 at high frequency (3600 Hz) was achieved with an average thickness of 8 mm compared to cellulose aerogel. The compressive Young's modulus of hybrid aerogels was also enhanced by 94.12%. [ABSTRACT FROM AUTHOR]

A droplet forming microfluidic chip was used to create droplets of precisely controlled size that contained a photocurable monomer as well as nanoparticles of magnetite and manganese dioxide. Manganese dioxide nanoparticles were shown to be effective for decomposing hydrogen peroxide to form oxygen bubbles that provided propulsion, which increased the rate of methylene blue decomposition by the magnetite nanoparticles through enhanced mixing. Dissolving the alginate fiber released the microparticles that contain base-metal catalysts for both the decomposition of hydrogen peroxide, and methylene blue, a common water contaminant [[2]]. [Extracted from the article]

The influence of the cellulose substrate on the electrochemical performance of supercapacitor electrode materials made of polypyrrole (PPy) and cellulose is investigated. Composites were synthesized by chemical polymerization of pyrrole on dispersed fibers of cellulose from Cladophora algae and dispersed wood cellulose-based commercial filter papers, respectively, as well as on Cladophora cellulose and filter paper sheets. The resulting composites, which were characterized using scanning electron microscopy, cyclic voltammetry, and elemental analysis, were found to exhibit specific charge capacities proportional to the PPy content of the composites. The highest specific capacity (i.e., 171 C/g composite or 274 C/g PPy) was obtained for composites made from dispersed Cladophora cellulose fibers. The higher specific capacities for the Cladophora cellulose composites can be explained by the fact that the Cladophora cellulose fibers were significantly thinner than the wood cellulose fibers. While the PPy was mainly situated on the surface of the Cladophora cellulose fibers, a significant part of the PPy was found to be present within the wood fibers of the filter paper-based composites. The latter can be ascribed to a higher accessibility of the aqueous pyrrole solution to the wood-based fibers as compared to the highly crystalline algae based cellulose fibers. The present results clearly show that the choice of the cellulose substrate is important when designing electrode materials for inexpensive, flexible and environmentally friendly paper-based energy storage devices. [ABSTRACT FROM AUTHOR]

Paper-based conductive electrode materials of polypyrrole (PPy) and nanocellulose (NC) have received much attention lately for applications in non-metal-based energy storage devices, ion exchange, etc. The aim of this study was to study how the primary characteristics of NC raw materials impact and electrochemical properties of conductive NC-PPy composite sheets. Three NC raw materials were used: Cladophora cellulose (NC) produced at Uppsala University, Cladophora cellulose (NC) produced at FMC Biopolymer, and microfibrillated cellulose (NC) produced at Innventia AB. Composite paper sheets of PPy coated on the substrate NC material were produced. The NC raw materials and the composites were characterized with a battery of techniques to derive their degree of crystallinity, degree of polymerization, specific surface area, pore size distribution, porosity, electron conductivity, charge capacity and tensile properties. It was found that the pore size distribution and overall porosity increase upon coating of NC fibres for all the samples. The charge capacity of the composites was found to decrease with the porosity of the samples. It was further found that the mechanical strength of the pristine NC sheets was largely dependent on the overall porosity, with NC having the highest mechanical strength and lowest porosity in the series. The mechanical properties of the composite NC-PPy sheets were significantly diminished as compared with pristine NC sheets because of the impaired H-bonding between fibres and PPy-coated nanofibres. It was concluded that to improve the mechanical properties of PPy-NC sheets, a fraction of additive bare NC fibres is beneficial. Future study may include the effect of both soluble and insoluble additives to improve the mechanical strength of PPy-NC sheets. [ABSTRACT FROM AUTHOR]

Poly(3, 4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) was used to directly disperse multiwalled carbon nanotubes (MWNTs) into a stable solution without the aid of any other surfactants. The solution was coated onto paper substrates and was subsequently dried via two different methods: conventional multidirectional drying and a special unidirectional drying method with the aid of a ceramic heating board. The samples that were dried using the unidirectional drying method had a lower resistance than when dried with the conventional drying method, which allowed it to have a better conductivity. For solutions containing 1-4 mg/mL MWNTs, which were dispersed with 1 mg/mL PEDOT:PSS, the measured conductivity ranged from 21 ± 0.5 to 46 ± 10 S/cm. These values are one to three orders of magnitude higher than those obtained for MWNT films often reported in the literature as well as for films we fabricated using MWNTs dispersed with SDBS, or PEDOT:PSS solution by itself. AFM and SEM images showed that the surface of MWNTs films made with PEDOT:PSS as a surfactant was very smooth and the layers tended to be thinner than when made with the other surfactants. It was demonstrated using FTIR analysis that the MWNTs become part of the 3D structure of the paper substrate material because chemical bonding between the PEDOT:PSS, the MWNTs and the paper fibers occurred during the drying stage. [ABSTRACT FROM AUTHOR]

Pt/Al2O3 catalyst powder was successfully incorporated in a microstructured paper-like matrix composed of a ceramic fiber network, by use of a simple papermaking technique. As-prepared composite, denoted paper-structured catalyst, was applied to the reduction of nitrogen oxide (NO X) in the presence of propene, for exhaust gas purification. The paper-structured catalyst demonstrated higher NO X reduction efficiency and more rapid thermal responsiveness than a conventional Pt-loaded honeycomb catalyst, indicating that the paper-like structure with interconnected pore spaces contributes to effective transport of heat and reactants to the catalyst surfaces. Furthermore, the paper-structured catalyst with the appearance of flexible paperboard has a high degree of utility. The efficiency of utilization of Pt catalyst was improved by using hierarchically assembled paper-structured catalysts with preferential location of Pt catalyst in the upper part. The paper-structured catalyst composite with paper-like utility and porous microstructure is thought to be a promising catalytic material for efficient NO X gas purification. [ABSTRACT FROM AUTHOR]

A novel microstructured catalyst that consists of Cu/ZnO catalyst powders and ceramic fibers was successfully prepared using pulp fibers as a tentative matrix by a papermaking technique. As-prepared material, called a paper-structured catalyst, possessed porous microstructure with layered ceramic fiber networks (average pore size ca. 20 μm, porosity ca. 50%). In the process of methanol autothermal reforming (ATR) to produce hydrogen, paper-structured catalysts demonstrated both high methanol conversion and low concentration of undesirable carbon monoxide as compared with catalyst powders and pellets. The catalytic performance of paper-structured catalysts depended on the use of pulp fibers, which were added in the paper-forming process and finally removed by thermal treatment before ATR performance tests. Confocal laser scanning microscopy and mercury intrusion analysis suggested that the tentative pulp fiber matrix played a significant role in regulating the fiber-network microstructure inside paper composites. Various metallic filters with different average pore sizes, used as supports for Cu/ZnO catalysts, were subjected to ATR performance tests for elucidating the pore effects. The tests indicated that the pore sizes of catalyst support had critical effects on the catalytic efficiency: the maximum hydrogen production was achieved by metallic filters with an average pore size of 20 μm. These results suggested that the paper-specific microstructures contributed to form a suitable catalytic reaction environment, possibly by promoting efficient diffusion of heat and reactants. The paper-structured catalyst with a regular pore microstructure is expected to be a promising catalytic material to provide both practical utility and high efficiency in the catalytic gas-reforming process. [ABSTRACT FROM AUTHOR]