Advanced Engineering Materials Research Articles

Strengthening and toughening mechanisms of γ-TiAl dominated by shear induced “catching bonds”

TiAl alloys, especially polysynthetically twinned (PST) TiAl, have great potential to be an advanced lightweight engineering materials for key aero-engines components like turbine blades due to their high service temperature. Most researches focus on improving the strength and ductility of TiAl, but the origin of strengthening and toughening mechanisms remain unexplored so far. This work aims at understanding the chemical bond related intrinsic mechanical behavior in essence and revealing the origin of excellent mechanical properties of TiAl alloy. We found that the excellent ductility of γ-TiAl origins from the metallic catching bonds (Ti-Ti and Al-Al) and the high strength is due to high strength Ti-Al covalent catching bond. The (111)/[112̅] system is most likely to be activated under pressure. The pure shearing along (111)/[112̅] leads to the interlayer slip of 1/6 [112̅] Burger vector with the breakage and reformation of Ti-Ti, Al-Al metallic bonds (“catching bonds”). The deformation mechanisms are attributed to the metallic catching bonds induced twin boundary (TB) formation, TB migration, superlattice intrinsic stacking fault (SISF) formation (detwinning) and SISF annihilation. These processes can continuously dissipate the strain energy, resulting in the excellent ductility of γ-TiAl. The structure becomes a hard slip system of (111)/ [1̅1̅2], and the ideal shear strength is 16.5GPa, which is about three times higher than that along (111)/ [112̅], on account of the high strength covalent catching bonds (Ti-Al) dominate the deformation mechanism of 1/2[1̅1̅2] full dislocation. The generalized stacking fault energy (GSFE) shows the true atomic slip path along 1/2[1̅1̅2] perfect dislocation (provide a degree of ductility) is: 1/2[1̅1̅2] → 1/6[12̅1] + 1/6[1̅1̅2] + 1/6[2̅11] + 1/6[1̅1̅2], which agrees well with the previous experimental results.

Design and Analysis of Yoshimura Tubular Origami Mechanisms

The Yoshimura tubular origami mechanism possesses numerous advantageous properties and, when integrated with advanced material technologies, can be applied across various engineering disciplines. However, current research on Yoshimura origami predominantly focuses on centrally symmetric tubular origami mechanisms, which restricts the structural forms and motion patterns of these mechanisms. Drawing inspiration from the biological concept of “morphological variation,” we propose a novel tubular origami mechanism based on the Yoshimura pattern, which is the main contribution of this research. We analyze the Yoshimura planar crease elements and introduce both heterocellular and homocellular tubular origami mechanisms. Furthermore, we establish the origami topology matrices for the Yoshimura tubular origami mechanisms. This research also investigates complex motion forms that differ from traditional Yoshimura origami mechanisms, including macroscopic twisting and compound movements, thereby providing an intuitive design approach and extensive structural guidance for research in Yoshimura tubular origami engineering. Based on the tubular origami mechanism, we created an origami robot and investigate its motion characteristics.

Optimizing Interfacial Charge Dynamics and Quantum Effects in Heterodimensional Superlattices for Efficient Hydrogen Production.

Superlattice materials have emerged as promising candidates for water electrocatalysis due to their tunable crystal structures, electronic properties, and potential for interface engineering. However, the catalytic activity of transition metal-based superlattice materials for the hydrogen evolution reaction (HER) is often constrained by their intrinsic electronic band structures, which can limit charge carrier mobility and active site availability. Herein, a highly efficient electrocatalyst based on a VS2-VS heterodimensional (2D-1D) superlattice with sulfur vacancies is designed addressing the limitations posed by the intrinsic electronic structure. The enhanced catalytic performance of the VS2-VS superlattice is primarily attributed to the engineered heterojunction, where the work function difference between the VS2 layer and VS chain induces a charge separation field that promotes efficient electron-hole separation. Introducing sulfur vacancies further amplifies this effect by inducing quantum localization of the separated electrons, thereby significantly boosting HER activity. Both theoretical and experimental results demonstrate that the superlattice achieves a ΔGH* of -0.06eV and an impressively low overpotential of 46mV at 10 mA·cm-2 in acidic media, surpassing the performance of commercial Pt/C while maintaining exceptional stability over 15000 cycles. This work underscores the pivotal role of advanced material engineering in designing catalysts for sustainable energy applications.

Patent Trend Analysis in Construction Materials for Carbon Emission Reduction: A Topic Modeling Approach

The increasing concern over carbon emissions and climate change has led to great interest in research and innovation for construction materials to reduce environmental impact. This study employs topic modelling techniques to analyze patent trends in the field of advanced construction materials focusing on carbon emission reduction. The methodology involves the application of topic modelling algorithms, which is Latent Dirichlet Allocation (LDA), to categorize the latent thematic clusters within the patent corpus and to cluster patent technologies. The resulting topics identify key areas of technological advancement, providing insights into emerging trends and innovations. In addition, this study explores the interconnectivity between topics that will help develop solutions for carbon emission reduction. The analysis highlights the advanced materials technologies and their development to achieve sustainable solutions. This patent trend analysis can guide researchers and industry professionals and contribute to the understanding of global efforts to reduce carbon emissions in advanced construction materials.

Synthesis and luminescence characterizations of Ag and Na doped LiAlO2 for OSL dosimetry

Optically Stimulated Luminescence (OSL) materials are advanced technology materials widely used in critical applications from radiation dosimetry, biomedicine, and optical data storage to archaeometry. These materials store energy by trapping charge carriers and convert this energy back into light by optical stimulation. However, there are significant challenges such as control of trap distribution and complete understanding of luminescence mechanisms. This study aims to overcome these challenges by comprehensively investigating the luminescence characteristics of lithium aluminate (LiAlO2) pellet materials produced by the sol-gel method and enabling the development of a new OSL dosimetric material. The crystal structures of the synthesized materials were confirmed by X-Ray Diffraction (XRD) method and their morphologies were investigated by Scanning Electron Microscope (SEM). Detailed discussions on defect concentrations and lattice parameters of LiAlO2 are presented. To obtain promising luminescence signals for passive dosimetry, LiAlO2 were doped with various lanthanides (Ce and Gd) and metals (Cu, Ag, Na, Mg and Ca). Especially, the co-doping of Ag and Na ions provided a significant increase in Thermoluminescence (TL) and OSL signals. The effects of dopant elements on TL and OSL signals were investigated comprehensively, and the OSL components and lifetimes were analyzed in detail. As a result, it was determined that TL traps of the developed LiAlO2:Ag,Na pellets at 100 °C were the main source of OSL signals. The reusable OSL signals and almost linear dose-response ratio up to 2 Gy of this material make it a candidate for radiation dosimetry applications. While the developed LiAlO2:Ag,Na material exhibits promising OSL sensitivity and low fading over 2 weeks, the signal stability is dependent on an initial preheat treatment at 100 °C, which reduces around 80 % of the initial OSL signal associated with shallow traps. This characteristic supports the material’s application in dosimetry but may limit sensitivity in low-dose contexts.

Effect of High-Pressure Treatment on the Crystal Structure and Li+ Conduction Properties of Li3AlF6

All-solid-state batteries which are attracting attention as next-generation energy storage devices overcome the flammability of conventional lithium-ion batteries. These batteries achieve high safety and energy density through the use of non-flammable solid electrolytes, and could be used as the power sources for electric vehicles and electronic devices in the future. However, several challenges are remained for the practical application of all-solid-state batteries, which require the further development of solid electrolytes.Sulfide-based solid electrolytes, which are currently extensively studied, exhibit high Li+ ionic conductivity[1]. However, the sulfides have problems with atmospheric and electrochemical stability[1]. In 2018, Asano et al. have reported that lithium metal chlorides and bromides (Li3YCl6, Li3YBr6) exhibit high ionic conductivity, a wide electrochemical stability window, and excellent electrode interface stability[2]. However, these lithium metal chlorides and bromides have problems with atmospheric stability[3].My research focused on the lithium metal fluoride materials, which have excellent electrochemical stability and high air stability[4]. On the other hand, their low ionic conductivity due to the strong electronegativity of F- is challenging for the application. Li3AlF6, which has a monoclinic structure at room temperature, has been reported as the lithium ionic conductor[5]. The solid solution of Li3AlF6-Li2SiF6 in which the host Al3+ is substituted by Si4+ exhibited moderately high Li+ ionic conductivity of 3×10-5 S/cm at room temperature[6]. Li3AlF6-Li2SiF6 solid solution was mixture of monoclinic and orthorhombic Li3AlF6 and the positive relationship between the Li+ conductivity and the orthorhombic fraction was suggested[6].Therefore, we consider that Li+ conductivity can be further improved for other crystalline phases of Li3AlF6. In this study, Li3AlF6 is heated under 2 ~ 8 GPa (high-pressure treatment) to investigate the variation of the polymorphs under high-pressure. The Li+ conductivities of Li3AlF6 after high-pressure treatment are evaluated. Experimental method.LiF and AlF3 were mixed in a molar ratio of 3:1 and fused at 900℃ for 15min in the electric furnace set in a glovebox. Li3AlF6 was ball-milled using a ZrO2 vessel (45 mL) for 50 h. The high-pressure treatment was conducted using a cubic anvil-type apparatus. Li3AlF6 pellet with 5.6 mm was placed in the BN capsule (4.4 mm in diameter). Subsequently, this BN capsule was further inserted in the carbon tube heater(5.4 mm in diameter). This all-in-one capsule was embedded in the pyrophyllite cube (pressure-transmitting media), which was subjected to the high-pressure treatment. Li3AlF6 was heated to 500 ~ 700°C under 2 ~ 8 GPa. After high-pressure treatment, the crystalline phase of the sample was identified by XRD. For the conductivity measurement, the sample was grounded and pelletized at 450 MPa in the PEEK cylinder. The impedance was measured in a frequency range between 1 MHz to 1 Hz. Result.Fig. 1 shows the XRD patterns of the Li3AlF6 after high-pressure treatment at room temperature (bottom) and 500℃ (top). As show in Fig. 1(top) the diffraction pattern of Li3AlF6 (8 GPa, 500℃) was fitted by orthorhombic (Pna21), indicating the stabilization of the orthorhombic Li3AlF6 at ambient condition. The densities of monoclinic (C2/c) and orthorhombic (Pna21) Li3AlF6 are 2.84 g/cm3 and 2.90 g/cm3, respectively. Therefore, orthorhombic Li3AlF6 is considered to be more stable under high pressure condition. The crystal structure of Li3AlF6 is known as monoclinic structure at room temperature[6]. The lattice volume of Li3AlF6 doped with Si was decreased and the crystal structure was the mixed phase of orthorhombic and monoclinic[6]. Therefore, decreasing the lattice volume can be effective for the stabilization of orthorhombic Li3AlF6. On the other hand, the crystal structure of Li3AlF6(8 GPa, RT) was monoclinic(C2/c). It is considered that by heating at high pressure, Li3AlF6 maintained its high temperature phase[7]. The Li+ conductivity of high-pressure treated samples will be presented in the poster. Acknowledgement This work was supported by the NGK Environment Innovation Laboratory and JSPS KAKENHI Grant JP23H23447 Reference [1] J. Wu et al., Advanced Materials, vol. 33, no. 6. 2021.[2] T. Asano et al., Advanced Materials, vol. 30, no. 44, 2018[3] X. Li et al., Nano Lett, vol. 20, no. 6, pp. 4384–4392, 2020[4] M. Jin et al., Advanced Engineering Materials, vol. 25, no. 8. John Wiley and Sons Inc, 2023.[5] T et al., Solid State Ion, vol. 34, no. 3, pp. 201–205, 1989.[6] R. Miyazaki et al., ACS Appl Energy Mater, 2024,.[7] Jan L. Holm et al., Acta Chem. Scand. 23, 1969 Figure 1

3D-Printed Gas Diffusion Layers for Enhanced Mass Transport in Polymer Electrolyte Fuel Cells

Water management in polymer electrolyte fuel cells (PEFC), particularly the accumulation of liquid product water in the gas diffusion layer (GDL) on the cathode side, which mitigates the oxygen transport towards the catalytic surface, must be optimized for ideal performance [1]. The potential of 3D-printing has recently gained interest in the field of electrochemical flow cells to investigate and improve mass transport in porous transport layers of various applications, including PEFC [2,3,4].In this study we explore different 3D-printed structures that are used as cathode GDLs for PEFC. The objective is to guide the liquid product water through determined pathways by adjusting the throat size to form preferential percolation routes according to Young-Laplace law [5]. The GDLs are obtained from a 3D-printed polymer precursor that is subsequently carbonized in a tube furnace (Tc = 1200°C in N2 atmosphere, result shown in Figure 1a) and treated with a hydrophobic surface coating. The structures are assembled in a cell designed for X-ray diagnostics together with a commercial Freudenberg H2315C2 anode GDL and a Gore Primea CCM (A510.1/M815.15/C510.4) to form the membrane electrode assembly (MEA). The cross-section of one of these cells obtained from X-ray tomography is exemplarily shown for a “through-plane” cathode GDL in Figure 1b. To track the liquid water distribution and saturation in the GDL we perform current jumps from dry state to various current densities and employ operando X-ray radiography with a Lab CT, with a frame rate of 2 Hz. Additionally, the 3D water distribution after reaching steady state is captured by X-ray tomography at the end of each current jump experiment. Furthermore, we measure the electrochemical performance (see Figure 1c) and compare our results to a reference case (Toray, carbon paper GDL). Figure 1 . a) SEM images of the carbonized structure b) Cross section obtained from X-ray tomography of the cell assembly with the through-plane GDL c) Polarization curves and HFR of the through-plane cell as well as a reference cell with a commercial Toray material (two TGP-090 w. 10% PTFE sandwiched together). The cell was operated with H2/Air at T=50°C, p=1bar and 100% relative humidity on both sides References[1] J. Ihonen et. al., Journal of the Electrochemical Society, 2004, 151, pp. A1152-A1161[2] D. Niblett et. al., International Journal of Hydrogen Energy, 2022, 47, pp. 23393-23410[3] M. v. d. Heijden et. al., Advanced Materials Technologies, 2023, 8, 2300611[4] B. Huang et. al., Angewandte Chemie International Edition, 2023, e202304230[5] D. Niblett et. al., Journal of Power Sources, 2020, 471, 228427 Figure 1

Porous Silicon Nanowires: Evaluation of Thermal Properties By a Vamas Interlaboratory Comparison on Scanning Thermal Microscopy

The Versailles Project on Advanced Materials and Standards (VAMAS) has been established by G7 in 1982 and supports world trade in products dependent on advanced materials technologies, through International collaborative projects aimed at providing the technical basis for harmonized measurements, testing, specifications, and standards. It is composed by more than 15 Technical Working Areas devoted to the standardization and measurements of advanced materials. The participants are selected on a volunteering base and must represent at least the three international areas, Europe, Americas and East. The aim of this international interlaboratory comparison is to determine quantitatively the thermal properties of arrays of silicon nanowires measuring periodicity, diameter and height, effusivity and thermal conductance using scanning electron microscopy (SEM), atomic force microscopy (AFM) and scanning thermal microscopy (SThM). The samples are fabricated by INRiM and will be circulated among the interested partners starting from November 2024 for the SThM measurements. Data will be evaluated by CMI and INRiM and included in the VAMAS final report of the project. 1. Introduction The use of nanowires is diffused in several applications, ranging from photovoltaics to hydrogen production by photo catalysis, and the evaluation of the thermal properties is a critical assessment for their use. Scanning Thermal Microscopy is a promising technique for this purpose, but needs accurate study and calibration to measure values of thermal and conductivity. University, industry and calibration laboratories need reference samples and standards at the nanometric level for resolution certification of a variety of measuring instruments, such as Scanning Thermal Microscopes. There are no currently available nanowires arrays standard for thermal properties on the market and the measurements of nanowires thermal properties are typically qualitative and with too low uncertainty levels for the increasing needs of metrology. This VAMAS interlaboratory comparison will try to approach the thermal measurements of thermal properties of silicon and porous silicon nanowires with standardized samples and procedures. The main goals of the interlaboratory comparison will be:- Develop a standard based on silicon nanowires with different thermal conductance values, ranging from bulk silicon to silicon dioxide.- Develop a calibration procedure, combining experimental data from different characterization techniques, like Scanning Probe Thermal Microscopy and the 3ω method.- Evaluate measurement uncertainty.- Development of standardized procedures to define the thermal properties of the nanowires. 2. Samples fabrication and Interlaboratory comparison The samples to be measured will be fabricated by INRiM by MACE and Deep Reactive Ion Etching, aside of the Region of Interest (RoI) containing one or more arrays of porous silicon nanowires, three SiO2 layers with different thickness will allow a calibration close to the porous silicon thermal conductivity values [1] (Fig.1a). The MACE etching will be performed after nanosphere lithography and Au metallization [2] or by patterning the gold layer by FIB. Another set of samples will be fabricated by Electron Beam Lithography and Deep Reactive Ion Etching (Fig.1b). The SThM calibration and measurements will be performed following the works in reference [3,4]. The thermal conductivity of the initial substrates, both crystalline silicon and SiO2 layers, will be measured in parallel with the 3ω approach to obtain real values with a complementary and quantitative method. 3. Funding Participants fund their own involvement in the project. Samples for the interlaboratory comparison will be supplied by INRiM, the calibration procedure will be developed and diffused by CMI. 4. Deliverables and Dissemination Report will evaluate the variance observed in the associated measurement protocol, to guide further development. Results will be published in a peer-reviewed journal and will be proposed in ISO/IEC standards. 5. Conclusions The VAMAS project on the Thermal properties of Silicon and Porous Silicon Nanowires has been presented illustrating the fabrication methodology, the calibration approach, and the measurement protocol. The participation to the interlaboratory comparison is free and the measurement activity will start on November 2024.

Secondary Battery Application by Fabrication of Vanadium Mxene

Introduction Secondary batteries have become indispensable in our modern world, powering a wide range of electronic devices and electric vehicles. However, the growing demand for energy storage with higher energy density, faster charging capabilities, and improved sustainability has spurred research into novel materials for advanced battery technologies. MXene, a two-dimensional transition metal carbide or nitride, has emerged as a promising candidate for the secondary battery electrode materials because of high electrical conductivity, excellent mechanical stability, and a large interlayer spacing suitable for accommodating various guest ions. In this abstract, we discuss the synthesis methods of Vanadium MXene and its structural properties and electircal charcteristics for the secondary battery. The ability of a coin cell with MXene electrode to store and release energy and its stable cycling performance. Additionally, we explore the environmental benefits of using MXene, such as its sustainability and recyclability, which align with the growing emphasis on green energy storage solutions. Experimental and methodology The basic mixing conditions were set to 2:1.2:0.8 in the molar ratio of V, Al, and C for the formulation of MAX with vanadium metal as a raw material. For uniform mixing and MAX synthesis experiments, a ball mill mixing for 24 hours was conducted. To increase the reactivity between V, Al, and C during the heat treatment process, uniformly mixed raw materials are made into 50mm circular pellets through uniaxial compression and heat treatment is performed. For the etching chemical reaction of MAX, 10 g of MAX V2AlC was added to HF (100 ml) and reacted at 45 ℃ for 72 hours. Through an etching chemical reaction, the Maxine layer of the two-dimensional shape is peeled off, and the vanadium-based Maxine V2CTx is recovered as an intermediate material. After the etching process, the hydrofluoric acid remaining on the MXene surface was washed using centrifugation. MXene powder was recovered in liquid form, and dried by freeze-drying. For complete exfoliation of the MXene, layered V2CTx was added to teteramethylammonium hydroxide (TMA-OH, 10%, 50 ml) at room temperature to produce the delaminated V2CTx form. Results and discussion As a result of XRD analysis of the finally manufactured V2CTx, it was confirmed that a clear 2D peak appeared at about 7 degrees, verifying that V2AlC MAX was successfully exfoliated into V2CTx MXene. The disappearance of a sharp peak of MAX at 12 degree also confirmed that the layers of MAX were peeled off as two-dimensional shapes of V2CTx through a chemical etching reaction. From the AFM analysis results, it was confirmed that the MXene was completely exfoliated into a sheet form and had a thickness of about 2 nm or less. Constant current charge/discharge electrochemical experiments were performed on the coin cells manufactured using MXene in an aqueous electrolyte of 3 M ZnSO4. The synthesized vanadium MXene-based anode showed an initial discharge capacity of 126 mAh/g at a current density of 0.1 A/g, and a maximum capacity of 145 mAh/g was achieved in the initial 5 cycles. As the cycle progresses, the capacity decreases to 130 mAh/g, 89% life stability and >99% coulombic efficiency was shown up to 100 cycles. Acknowledgments This research was supported by Basic Research Project (21-3212-2) of the Korea Institute of Geoscience and Mineral Resources and the National Research Council of Science & Technology (NST) grant by the Korea government (MSIT) (No. CAP22071-000) References J. Pang, R.G. Mendes and A. Bachmatiuk, Chem. Soc. Rev., 48, 72 (2019).D. Xiong, X. Li, Z. Bai, S. Lu, Small, 14, 1703419 (2018).M. Naguib, V.N. Mochalin, M.W. Barsoum and Y. Gogotsi, Adv. Mater, 26, 992 (2014)B. Anasori, M.R. Lukatskaya and Y. Gogotsi, Nat. Rev. Mater, 2, 16098(2017).M. Okubo, A. Sugahara, S. Kajiyama, A. Yamada, Acc. Chem. Res., 51, 591 (2018)Z. Wei, Z. Peigen, T. Wubian, Q. Xia, Z. Yamei and S. ZhengMing, Mater. Chem. Phys., 206, 270 (2018). J. Zhang, Y. Zhao, X. Guo, C. Chen, C. L. Dong, R. S. Liu, C. P. Han, Y. Li, Y. Gogotsi and G. Wang, Nat. Catal., 1, 985 (2018).M. Naguib, M. Kurtoglu, V. Presser, J. Lu, J. Niu, M. Heon, L. Hultman, Y. Gogotsi and M. W. Barsoum, Adv. Mater., 23, 4248 (2011).S. Nam, J. Kim, V. H. Nguyen, M. Mahato, S. Oh, P. Thangasamy, C. W. Ahn and I. K. Oh, Adv. Mater. Technol, 7, 2101025 (2022). Figure 1

Kelvin Probe Techniques in Corrosion Science: Probing Reactivity with Spatial Resolution

More than 30 years after the introduction of the Kelvin Probe technique into corrosion research by Stratmann et al. [1, 2], Kelvin Probe techniques such as Scanning Kelvin Probe Microscopy (SKP) or Scanning Kelvin Probe Force Microscopy (SKPFM) are now quite routinely applied in the corrosion community. If the Kelvin probe is suitably calibrated, it allows to measure localized electrode/corrosion potentials [3]. Some main applications are for studying delamination of organic coatings and ion migration [2, 4, 5], mapping of hydrogen distribution [6], or characterizing potential differences on the surface of materials for assessing the risk of formation of Galvanic elements on the surface [7]. Besides such experiments where maps of the electrode potential are obtained, it is also possible to obtain meaningful information about the localized electrochemical activity, such as reaction kinetics of ORR, for instance [8]. There are different variants of how to use Kelvin Probe-based techniques to assess the activity of localized Galvanic coupling and also to monitor for instance the degree of inhibition of ORR by released inhibitors, such as Zn2+ [9]. In this presentation further and more recent examples will be presented.[1] S.G. Yee, R.A. Oriani, M. Stratmann, J. Electrochem. Soc. 138 (1991) 55-62[2] R. Feser, M. Stratmann. Materials and Corrosion 42 (1991) 187-195[3] R. Hausbrand, M. Sratmann, M. Rohwerder, J. Electrochem. Soc. 155 (2008) C369-C379 [4] C. Senoz, M. Rohwerder, Electrochim. Acta 56 (2011) 9588-9595[5] J. M. Prabhakar, A. de Vooys, M. Rohwerde, Npj Materials Degradation 6 (2022) 76[6] S. Evers, C. Senoz, M. Rohwerder, Science and Technology of Advanced Materials 14 (2013) 014201[7] P. Schmutz, G.S. Frankel, J. Electrochem. Soc. 145 (1998) 2295-2306[8] X. K. Zhong, et al., Chemelectrochem 8 (2021) 712-718[9] R. Krieg et al., Corros. Sci. 65 (2012) 119-127

Recent Development of Graphene-Based Composites for Electronics, Energy Storage, and Biomedical Applications: A Review

Nanomaterials are attractive materials for researchers because they have essential characteristics in terms of their properties. Carbon has an ample range of crystalline allotropes. Some, such as graphite and diamond, have been known since ancient times, while new forms of carbon with potential for various applications have been discovered in recent decades. Since the discovery of graphene 20 years ago, research has increased on composite materials that take advantage of carbon structures for their electrical, thermal, and mechanical properties and their ability to be synthesized at the nanometer scale. Graphene has stood out above other nanomaterials due to its surprising properties and high impact on technological research, so its uses have diversified in different areas of science such as medicine, electronics, engineering, etc. This work aims to show some new and innovative applications of graphene, on which we can see its versatility as engineering material. It also seeks to show its potential in research and development processes for its use. These are key components of advanced graphene-based materials systems under active development, with an eye on the future of advanced materials science and technology.

Heat treatment and codeposition of Co and Al on nickel-based superalloy DZ411 by CVD process

Co-deposition of aluminide coatings on the inner and outer surfaces of turbine blades using chemical vapor deposition (CVD) technology is a major challenge in the field of advanced materials engineering. To overcome this challenge, a sub-aluminum generator device was designed and Co-Al coatings with typical β-NiAl microstructure were successfully obtained on the inner and outer surfaces of the turbine blades in the present study. In addition, the effects of different heat treatment processes on the microstructures of the Co-Al coatings were also investigated, and the results show that the addition of heat treatment process can easily lead to the thinning of Co-Al coating thickness, the increase of oxidation degree as well as the emergence of different types of topological close packing (TCP) phases. The serious loss of Al would also lead to the occurrence of transition from β-NiAl phase to γʹ-Ni3Al phase. This study not only breaks through the limitations of conventional CVD equipment, but also provides valuable insights into the microstructural evolution of Co-Al coatings under different heat treatment conditions, and provides necessary conditions for further exploration of co-deposition technology for different types of coatings.

Optimizing Computation: A Biomimicry Design Spiral Approach to Algorithm Development

The increasing focus on biomimicry in the built environment shows that designers are becoming more conscious of the opportunities that nature presents for enhancing human and systemic functions. The field of advanced material technology has extensively used biomimicry. Nevertheless, there has been little in-depth discussion of its possibilities in environmentally conscious building practices. Numerous branches of the social and natural sciences have had an impact on the field of architecture; at the present time, biological principles are finding their way into design processes. From the earliest days of bio-architectural movements to the most recent ones, bioinspiration has shaped architectural practices towards a wide range of new methods. Nevertheless, the line between architectural bioinspiration that just mimics natural forms and the genuine comprehension of biological principles—the bedrock of sustainable development—is blurry when it comes to biomimicry. One of the biggest obstacles is the lack of cross-disciplinary cooperation between architects and biologists, which is exacerbated by the vast knowledge gap that exists between the creative process of building design and the scientific disciplines that pertain to biology. All sorts of spiral pathways, their properties, and how to use them to build and enhance other optimisation methods are described in great detail.

Unveiling the Monoclinic Phase in CsPbBr3-xClx Perovskite Crystals, Phase Transition Suppression and High Energy Resolution γ-Ray Detection.

All-inorganic CsPbBr3 and CsPbCl3 perovskites are promising materials for high-performance solar cells and advanced radiation detection technologies with high stability. Here we report that CsPbBr3-xClx (x = 0-3) crystals exhibit eutectoid behavior for the melting points and phase transition temperatures. The well-known halide perovskite cubic phase transition temperature shifts near room temperature (∼37 °C for CsPbBr2Cl). We conducted an extensive crystallographic analysis on single crystals of 7 different compositions, including the end members CsPbBr3 and CsPbCl3. Contrary to previous beliefs, we discovered they exhibit a monoclinic structure with space group symmetry P21/m at room temperature, rather than the orthorhombic Pnma. This new structural model is more precise and features a unit cell volume that is four times larger than that of the orthorhombic model. From high-quality single crystals of CsPbBr2Cl, grown by the Bridgman method, we constructed γ-ray detectors achieving an energy resolution of 7.2% at 200 V for 57Co radiation. Thermally stimulated current spectroscopy of the CsPbBr2Cl samples revealed that the defect densities in crystals from different regions of the ingot were relatively uniform, with values of ∼4.72 × 1012 and ∼5.09 × 1012 cm-3. These findings indicate that low deep-level defect densities can be achieved that are consistent with the notable performance of the CsPbBr2Cl perovskite as a high-energy γ radiation detector.

Prevention and Control of Biofouling Coatings in Limnoperna fortunei: A Review of Research Progress and Strategies.

The increasing environmental concerns of conventional antifouling coatings have led to the exploration of novel and sustainable solutions to address the biofouling caused by Limnoperna fortunei. As a rapidly expanding invasive species, the fouling process of Limnoperna fortunei is closely associated with microbial fouling, posing significant threats to the integrity of aquatic infrastructure and biodiversity. This review discusses recent progress in the development of non-toxic, eco-friendly antifouling coatings that are designed to effectively resist biofouling without using toxic chemicals. Recent research has focused on developing novel non-toxic coatings that integrate natural bioactive components with advanced material technologies. These formulations not only meet current environmental standards and exhibit minimal ecological impact, but also possess significant potential in preventing the attachment, growth, and reproduction of Limnoperna fortunei. This review aims to provide scientific guidance by proposing effective and sustainable solutions to address the ecological challenges presented by Limnoperna fortunei. The insights gained from current research not only reveal novel antifouling methods, but also identify key areas for further investigation aimed at enhancing performance and environmental compatibility.

Multi-cation doped CuCrO[formula omitted] crystallite matrix: Exploring bandgap tunability through Ni-Zn and Ni-Zn-Mg doping for optoelectronic application

Bandgap tuning is a key approach to optimizing materials for advanced technologies, enabling the development of more efficient and specialized devices. In this study, we demonstrate the tunability of the bandgap of CuCrO2 from 2.38 to 4.37 eV via single cation-doping with Ni and Zn, and multi-cation doping with Ni-Zn and Ni-Zn-Mg. XRD analysis reveals structural changes due to lattice distortions by cationic substitution, while FESEM shows the impact of doping on particle size, surface morphology, and crystallinity. The lamellar structure observed with multi-cation doping in FESEM investigations indicates increased structural disorder and defects, causing tailing above the valence band and below the conduction band, significantly reducing the bandgap. The effect of Zn-Ni doping on the lattice is reversed with Mg2+ insertion due to p-p orbital interactions between Mg2+-O, replacing the d-p interaction in the Cr3＋-O bond, as confirmed by optical studies. UV–Vis and photoluminescence analyses reveal significant shifts in bandgaps and emission spectra, with Ni doping yielding a bandgap of 3.97 eV, Zn doping 3.16 eV, Zn-Ni doping expanding it to 4.37 eV, and Zn-Ni-Mg doping reducing it to 2.38 eV. The dopants also affect emission characteristics, including band edge and deep-level emissions. This study provides valuable insights into the relationship between cationic doping and material properties, guiding the design of CuCrO2-based materials with tailored functionalities.

Exploring multimetal interactions between FeNi3 alloy and Lu3Ga5O12 metal oxide for improved water splitting performance

The production of energy from fossil fuels generates greenhouse gases, leading to global warming and various environmental impacts. Extensive research into sustainable alternative fuels has identified hydrogen (H2) as a viable option. With net zero carbon emissions, hydrogen presents a promising solution for sustainable and renewable energy. This study employs a simple gel-matrix method to fabricate Ni-Fe alloy-based nanocomposites in alkaline media (1 M KOH). Achieving outstanding performance in hydrogen generation through the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), with impressive turn-over frequencies (TOF) of 2.98 s−1 at 177 mV and 1.48 s−1 at 219 mV. Nanocomposite’s unique structure enhances electroactive surface area (347.5 cm2/gram), extending electrocatalytic active sites and durability to 60 h. It shows excellent performance, characterized by low Tafel slopes of 50 mV/dec and 37 mV/dec, and minimal overpotentials of 219 mV for the oxygen evolution reaction (OER) and 177 mV for the hydrogen evolution reaction (HER), reaching a current density of 10 mA cm−2. This study presents a method for synthesizing high-performance, sustainable metal-alloy/garnet hybrid electrocatalysts, offering a new frontier in design of next-generation materials for advanced energy conversion technologies.

Healable, Recyclable, and Upcyclable Gel Membranes for Efficient Carbon Dioxide Separation

AbstractIonic liquids (ILs) are prized for their selective dissolution of carbon dioxide (CO2), leading to their widespread use in ionogel membranes for gas separation. Despite their advantages, creating sustainable ionogel membranes with high IL contents poses challenges due to limited mechanical strength, leakage risks, and poor recyclability. Herein, we leverage copolymerized and supramolecularly bound ILs to develop ionogel membranes with high mechanical strength, zero leakage, and excellent self‐healing and recycling capabilities. These membranes exhibit superior ideal selectivity for gas separation compared to other reported ionogel membranes, achieving a CO2/nitrogen selectivity of 61.7 and a CO2/methane selectivity of 24.6, coupled with an acceptable CO2 permeability of 186.4 Barrer. Additionally, these gas separation ionogel membranes can be upcycled into ionic skins for sensing applications, further enhancing their utility. This research outlines a strategic approach to molecularly engineer ionogel membranes, offering a promising pathway for developing sustainable, high‐performance materials for advanced gas separation technologies.

Mapping the evolution of 3D printing in cardio-thoracic diseases: a global bibliometric analysis.

Despite the growing research on 3D printing (3DP) in cardio-thoracic diseases, comprehensive bibliometric analyses remain scarce. This study aims to bridge this gap by identifying key research trends and hotspots within the field. A bibliometric analysis was conducted on publications from 1991 to 2024 using data from the Web of Science Core Collection, with analysis performed using VOSviewer, CiteSpace, and the R package 'bibliometrix'. The analysis included 2,836 documents authored by 14,206 researchers across 85 countries. A significant rise in annual publications was observed, with the United States, China, and the United Kingdom leading in contributions. Prominent institutions, including Stanford University, were highlighted, while Scientific Reports and Biomaterials were identified as influential journals. Key research areas encompass cardiovascular, lung, and breast diseases, along with chest wall reconstructions, with emerging trends focusing on advanced materials for drug delivery and tissue engineering. This comprehensive bibliometric analysis of 3DP in cardio-thoracic diseases reveals global research trends, emerging themes, and the crucial role of 3DP in advancing medical education and personalized treatment, highlighting areas for future research and development.

Implementing an entrepreneurial mindset through activities in recycling course

There is an urgent need to connect theoretical knowledge acquired in engineering courses with practical, real-world applications to promote knowledge sustainability. To address this need, an entrepreneurially minded learning (EML) approach was implemented in an elective course titled Recycling of Advanced Engineering Materials. This approach enables students to explore the phases and interactions involved in product development by formulating and communicating requirements and solutions that consider both societal benefits and economic constraints, reflecting the entrepreneurial mindset behaviors outlined by the Kern Entrepreneurial Engineering Network (KEEN). The EML activities included hands-on recycling experiences and visits to local recycling companies, emphasizing motivation and overcoming conceptual learning barriers while enhancing students' entrepreneurial knowledge and reasoning skills. This study analyzed students' performance in exams, class discussions, and term projects alongside their perceptions of the engagement activities. Survey questions were designed to assess the impact of these activities on the development of students' entrepreneurial knowledge and abilities, utilizing a Likert scale for responses. Results from survey questions indicated that the EML approach significantly enhanced students' entrepreneurial knowledge and reasoning abilities, motivating them to engage in critical thinking and self-directed learning to address real-world challenges.