Structure Properties Of Materials Research Articles

Evaluation of influence of dissolved oxygen on corrosion behaviors of FeCrW model alloys in 360 °C water

The dissolved oxygen in a coolant can affect the oxidation properties of structural materials. A desirable oxide phase formation is achieved by manipulating the oxygen level in the coolant, which can mitigate structural material degradation in nuclear power plants. Therefore, the role of dissolved oxygen in the corrosion of structural materials in aqueous environments needs to be understood. In this study, a short-term corrosion test (up to 300 h) of Ferritic/Martensitic steels (F/M steels; FeCrW model alloys), namely, Fe12Cr1W, Fe9Cr1W, and Fe9Cr, in stagnant water at 360 °C was performed in a pressurized autoclave with the dissolved oxygen concentration controlled to 1 ppm or a very low level (<1 ppm). The results of the corrosion tests showed that an increase in the oxygen level in the water elevated the corrosion potential, allowing the phase transition of iron oxide from magnetite (Fe3O4) to hematite (Fe2O3), whereas there was no significant correlation between the concentrations of the alloying elements Cr and W and the oxide growth rate. In addition, hematite was found to mitigate further oxide growth. Finally, a mechanism for the growth of the initial oxide layer was proposed based on the experimental results.

Structural, dielectric and magnetic properties of MFeNbO6 materials (M=Ti, Zr, Hf)

We study the structural, magnetic and electronic properties of MFeNbO6 materials (where A = Ti, Zr or Hf). TiFeNbO6 crystallises with the disordered rutile structure with the P42/mnm space group. Increasing the ionic radii of the M4+ cation going from Ti4+ (0.605 Å) to Zr4+ (0.72 Å) and Hf4+ (0.710 Å) results in a buckling of the octahedral chains with these materials crystallising with the disordered α-PbO2 structure (space group Pbcn). In contrast, with previous reports for TiFeNbO6 we find no evidence of relaxor ferroelectric behaviour with all three materials instead exhibiting Maxwell-Wagner-like relaxation. Impedance spectroscopy confirms semiconductor behaviour. Magnetically, all three materials can be described by infinite irregular antiferromagnetic S = 5/2 chains with weak ferromagnetism below 10 K. These chains have random directions of propagation between nearest Fe–Fe neighbours consistent with the disordered nature of these materials. We observed a negative imaginary part of the ac susceptibility related to the defect magnetic topology.

Toward Bioactive Hydrogels: A Tunable Approach via Nucleic Acid-Collagen Complexation

Abstract Purpose Nucleic acid-collagen complexes (NACCs) are unique biomaterials formed by binding short, monodisperse single-stranded DNA (ssDNA) with type I collagen. These complexes spontaneously generate microfibers and nanoparticles of varying sizes, offering a versatile platform with potential applications in tissue engineering and regenerative medicine. However, the detailed mechanisms behind the nucleic acid-driven assembly of collagen fibers still need to be established. We aim to understand the relationship between microscopic structure and bulk material properties and demonstrate that NACCs can be engineered as mechanically tunable systems. Methods We present a study to test NACCs with varying molar ratios of collagen to random ssDNA oligonucleotides. Our methods encompass the assessment of molecular interactions through infrared spectroscopy and the characterization of gelation and rheological behavior. We also include phase contrast, confocal reflectance, and transmission electron microscopy to provide complementary information on the 3D structural organization of the hydrogels. Results We report that adding DNA oligonucleotides within collagen robustly reinforces and rearranges the hydrogel network and accelerates gelation by triggering rapid fiber formation and spontaneous self-assembly. The elasticity of NACC hydrogels can be tailored according to the collagen-to-DNA molar ratio, ssDNA length, and collagen species. Conclusion Our findings hold significant implications for the design of mechanically tunable DNA-based hydrogel systems. The ability to manipulate hydrogel stiffness by tailoring DNA content and collagen concentration offers new avenues for fine tuning material properties, enhancing the versatility of bioactive hydrogels in diverse biomedical applications. Lay Summary This work is an example of forming fibers and gels with tunable elasticity that stems from the complexation of short-length nucleic acids (on the order of size of aptamers) and collagen, which can be potentially extended to a variety of functionalized hydrogel designs and tailored biomedical applications. Incorporating DNA induces mechanical changes in NACCs. Graphical Abstract

Lithium-Ion Dynamic and Storage of Atomically Precise Halogenated Nanographene Assemblies via Bottom-Up Chemical Synthesis.

Graphene has received much scientific attention as an electrode material for lithium-ion batteries because of its extraordinary physical and electrical properties. However, the lack of structural control and restacking issues have hindered its application as carbon-based anode materials for next generation lithium-ion batteries. To improve its performance, several modification approaches such as edge-functionalization and electron-donating/withdrawing substitution have been considered as promising strategies. In addition, group 7A elements have been recognized as critical elements due to their electronegativity and electron-withdrawing character, which are able to further improve the electronic and structural properties of materials. Herein, we elucidated the chemistry of nanographenes with edge-substituted group 7A elements as lithium-ion battery anodes. The halogenated nanographenes were synthesized via bottom-up organic synthesis to ensure the structural control. Our study reveals that the presence of halogens on the edge of nanographenes not only tunes the structural and electronic properties but also impacts the material stability, reactivity, and Li+ storage capability. Further systematic spectroscopic studies indicate that the charge polarization caused by halogen atoms could regulate the Li+ transport, charge transfer energy, and charge storage behavior in nanographenes. Overall, this study provides a new molecular design for nanographene anodes aiming for next-generation lithium-ion batteries.

Promoting Cross-Link Reaction of Polymers by the Matrix-Filler Interface Effect: Role of Coupling Agents and Intermediate Linkers.

The matrix-filler interface effect plays an important role in determining the structural stability and mechanical properties of polymer composite materials, which remain ambiguous and need to be studied. The network-forming dynamics of poly(3,3-bis (azidomethyl) oxetane-tetrahydrofuran) (PBT) at the ammonium perchlorate (AP) surface was studied by using atomistic molecular dynamics simulation, considering the additives of curing agent toluene diisocyanate (TDI), cross-linker trimethylolpropane (TMP), and coupling agent triethanolamine (TEA). The presence of the AP surface promotes chain cross-link reaction, which is attributed to the increased production of intermediate linkers formed by TDI, TMP, and TEA. The intermediate linker has three reactive sites that can react with PBT main chains to form a cross-linked structure. Owing to the strong interaction with the AP surface, the coupling agent TEA plays a dominant role in forming the intermediate linker. At the early stage of network forming (reaction ratio r < 30%), the AP surface adsorbs TEA, which leads to a maximum contact density to PBT. As r increases to 60%, the density of intermediate linkers near the AP surface reaches a maximum value. Consequently, the chain cross-link reactions between the intermediate linker and PBT main chains are enhanced as r > 60%. This work explains the micromechanism of the promotion of chain cross-link reaction by the interface effect and provides important insights on designing polymer materials with high mechanical properties.

Effect of Thermal Activation on the Structure and Electrochemical Properties of Carbon Material Obtained from Walnut Shells.

A simple activation method has been used to obtain porous carbon material from walnut shells. The effect of the activation duration at 400 °C in an atmosphere with limited air access on the structural, morphological, and electrochemical properties of the porous carbon material obtained from walnut shells has been studied. Moreover, the structure and morphology of the original and activated carbon samples have been characterized by SAXS, low-temperature adsorption porosimetry, SEM, and Raman spectroscopy. Therefore, the results indicate that increasing the duration of activation at a constant temperature results in a reduction in the thickness values of interplanar spacing (d002) in a range of 0.38-0.36 nm and lateral dimensions of the graphite crystallite from 3.79 to 2.52 nm. It has been demonstrated that thermal activation allows for an approximate doubling of the specific SBET surface area of the original carbon material and contributes to the development of its mesoporous structure, with a relative mesopore content of approximately 75-78% and an average pore diameter of about 5 nm. The fractal dimension of the obtained carbon materials was calculated using the Frenkel-Halsey-Hill method; it shows that its values for thermally activated samples (2.52, 2.69) are significantly higher than for the original sample (2.17). Thus, the porous carbon materials obtained were used to fabricate electrodes for electrochemical capacitors. Electrochemical investigations of these cells in a 6 M KOH aqueous electrolyte were conducted by cyclic voltammetry, galvanostatic charge/discharge, and impedance spectroscopy. Consequently, it was established that the carbon material activated at 400 °C for 2 h exhibits a specific capacity of approximately 110-130 F/g at a discharge current density ranging from 4 to 100 mA/g.

Synthesis of Chitosan and Ferric-Ion (Fe3+)-Doped Brushite Mineral Cancellous Bone Scaffolds.

Biodegradable scaffolds are needed to repair bone defects. To promote the resorption of scaffolds, a large surface area is required to encourage neo-osteogenesis. Herein, we describe the synthesis and freeze-drying methodologies of ferric-ion (Fe3+) doped Dicalcium Phosphate Dihydrate mineral (DCPD), also known as brushite, which has been known to favour the in situ condition for osteogenesis. In this investigation, the role of chitosan during the synthesis of DCPD was explored to enhance the antimicrobial, scaffold pore distribution, and mechanical properties post freeze-drying. During the synthesis of DCPD, the calcium nitrate solution was hydrolysed with a predetermined stoichiometric concentration of ammonium phosphate. During the hydrolysis reaction, 10 (mol)% iron (Fe3+) nitrate (Fe(NO3)3) was incorporated, and the DCPD minerals were precipitated (Fe3+-DCPD). Chitosan stir-mixed with Fe3+-DCPD minerals was freeze-dried to create scaffolds. The structural, microstructural, and mechanical properties of freeze-dried materials were characterized.

Structural, optical, and photocatalytic properties of nano-scaled g-C3N4 materials

Structural, optical, and photocatalytic properties of nano-scaled g-C3N4 materials

Influence of Subsoil and Building Material Properties on Mine-Induced Soil–Structure Interaction Effect

Soil–structure interaction (SSI) refers to the dynamic interaction between a structure and the surrounding soil on which it rests. The behavior of the soil can significantly affect the response of the building structure. In the context of civil engineering and structural analysis, SSI becomes particularly important when considering the response of structures to dynamic loads such as earthquakes or so-called paraseismic loads, e.g., mining tremors. Several factors contribute to SSI. Soil and building structure material properties, foundation type, and loading conditions are the most important parameters. The article concerns SSI in the case of mining rock bursts in Poland. The influence of changes in site material conditions and building material properties on the SSI phenomenon was investigated. A few variants of different properties of typical construction materials (brick, reinforced concrete, and cellular concrete) in the case of selected representative building structure were considered. The subsoil material properties from the wide range were also taken into account. Numerical three-dimensional finite element method (FEM) analysis was applied. The adopted models of the soil-structure system were verified by data from in situ experimental vibration measurements. A significant influence of the subgrade material and the building structure material on the SSI was demonstrated.

Effects of Selective Laser Melting Process Parameters on Structural, Mechanical, Tribological and Corrosion Properties of CoCrFeMnNi High Entropy Alloy

AbstractThe structural, tribological, mechanical, corrosion, and other properties of materials produced by laser-based powder bed fusion additive manufacturing methods are significantly affected by production parameters and strategies. Therefore, understanding and controlling the effects of the parameters used in the manufacturing process on the material properties is extremely important for determining optimum production conditions and for saving time and materials. This study aimed to determine the optimal laser parameter values for CoCrFeMnNi high-entropy alloy powders using the selective laser melting (SLM) method. The layer thickness was kept constant during experimentation. 5 different laser powers and 10 varying laser scanning speeds were tested, with hatch spacing from 30 to 90%. After determining the optimal laser parameters for SLM, prismatic samples were fabricated in different build orientations (0°, 45°, and 90°), and subsequently, their structural, mechanical, tribological, and corrosion properties were compared. Melt pool morphology could not be obtained at 20—40 and 60W laser powers and at all laser scanning speeds used at these laser powers. At 100 W laser power, 600 mm/s laser scanning speed, and 70% hatch spacing parameters, an ultimate tensile stress of 550 MPa and elongation of 48% were obtained. Among the samples produced in different build orientations, the sample produced with a 0° build orientation exhibited the highest relative density (99.94%), the highest microhardness (201.2 HV0.1), the lowest friction coefficient (0.7025), and the lowest wear and corrosion rates (0.7875 mpy). Additionally, SLM parameters were evaluated to have a significant impact on the performance of all properties of the samples. Graphical Abstract

Development of New Polyimide/Spirulina Hybrid Materials: Preparation and Characterization

This study presents the synthesis and characterization of polyimide (PI-2) films incorporated with spirulina powder for potential biomedical applications. The synthesis of PI-2 was achieved through a two-step polycondensation reaction using N-methyl-2-pyrrolidone (NMP) as the solvent. The incorporation of spirulina was systematically varied to investigate its effects on the structural and surface properties of the hybrid materials. Scanning electron microscopy revealed a tightly bound interface between spirulina and the PI-2 matrix, indicating effective dispersion and strong interfacial adhesion. Profilometry and Raman spectroscopy confirmed the homogeneous integration of spirulina within the polymer matrix, with resulting variations in surface roughness and chemistry. Contact angle measurements demonstrated altered wettability characteristics, with increased hydrophilicity observed with spirulina incorporation. Furthermore, blood component interaction studies indicated the variations in adhesion behavior observed for red blood cells, platelets, and plasma proteins. Water uptake studies revealed enhanced absorption capacity in PI-2 films loaded with spirulina, highlighting their potential suitability for applications requiring controlled hydration. Overall, this comprehensive characterization elucidates the potential of PI-2/spirulina hybrid materials for diverse biomedical applications, offering tunable properties that can be tailored to specific requirements.

The effect of doping different amounts of boron on the corrosion resistance and biocompatibility of TiO2 nanotubes synthesized on SLM Ti6Al4V samples

This comprehensive study investigates the corrosion and biocompatibility performances of boron-doped TiO2 nanotubes (TNT) synthesized on Ti6Al4V alloy produced by the selective laser melting (SLM) process. Structural analysis reveals a consistent reduction in nanotube diameter across varying boron doping levels (0.05 - 2 M boric acid doping), with B4-TNT exhibiting the smallest diameter at 190 nm. Boron incorporation induces phase transformation and decreases in diameter of nanotubes, influencing the material's structural properties. Corrosion resistance assessments indicate a significant enhancement, with B4-TNT demonstrating the highest polarization resistance (Rt = 2849.03 kΩ.cm2). The observed improvements are attributed to the combination of reduced nanotube diameter, altered phase structure, and increased polarization resistance, collectively contributing to enhanced corrosion resistance. Biocompatibility experiments conducted with human fibroblast cells (HDFa) reveal that B-doped TNTs foster increased cell viability compared to undoped TNT and uncoated alloy surfaces. These findings underscore the potential of boron doping as a strategic approach to improve corrosion resistance and enhance the biocompatibility of Ti6Al4V implants. This study provides valuable insights for advancing materials in biomedical applications with improved structural, corrosion-resistant, and biocompatible properties.

Layer-by-Layer Construction of Antibacterial and Anticoagulant Blood Contacting Materials.

Vascular transplantation is a common treatment for Cardiovascular disease (CVD). However, the mismatch of mechanical, structural, or microenvironmental properties of materials limits the clinical application. Therefore, the functional construction of artificial vessels or other blood contact materials remains an urgent challenge. In this paper, the composite nanofibers of polycaprolactone (PCL) with dopamine and polyethylenimine (PEI) coating are first prepared, which are further self-assembled by anticoagulant hirudin (rH) and antimicrobial peptide (AMP) of HHC36 through layer-by-layer (LBL) method. The results of FTIR and XPS analysis show that hirudin and AMP are successfully loaded on PEI-PDA/PCL nanofibers and the hydrophilicity is improved. They also show good mechanical properties that the ultimate tensile strength and elongation at break are better than natural blood vessels. The antibacterial results show that the antibacterial effect is still 93% against E. coli on the fifth day because of the stable and continuous release of HHC36 and rH. The performance of anticoagulant activity also exhibited the same results, which APTT is even 9.7s longer in the experimental group than the control group on the fifth day. The novel materials would be effectively solve the formation of thrombosis around artificial blood vessel grafts and the treatment of inflammation.

Rate-dependent energy dissipation of graded viscoelastic structures fabricated by grayscale vat photopolymerization

A major benefit of additive manufacturing technologies is precise control over structural topologies and material properties, which allows to tailor, for instance, energy absorption and dissipation. While vat photopolymerization is generally restricted to a single material, grayscale masked stereolithography (gMSLA) allows to customize material behavior by grading the light intensity within a structure. This study investigates the impact and opportunities of grayscale grading strategies on the rate-dependent mechanical behavior of structures fabricated by gMSLA. Considering the viscoelastic nature of polymers, rate-dependent energy dissipation is explored, introducing a parametric linear viscoelastic constitutive model for varying grayscales. The investigation includes the comprehensive characterization of mechanical properties, numerical finite element simulation, validation through experimental procedures, and exploration of dissipation energy under different strain rates. In this way, a rational function successfully determines the critical strain rate at which the maximum dissipation occurs. Overall, the research offers a comprehensive investigation of the mechanical dissipation behavior of graded 3D printed structures, laying the foundation for further studies and advancements aimed at optimizing these structures for enhanced energy absorption capabilities.

Regular relations of the composition, structure and properties of crystals of hydrogen-containing compounds

Research subject. Crystals of hydrogen-containing compounds belonging to the superprotonic family. Aim. To obtain knowledge about regular relations between composition, atomic structure, real structure and physical properties of materials, with the purpose of elucidating processes occurring in condensed state and forming the basis for modification of known or obtaining new compounds. Materials and methods. Experimental data were obtained using a set of complementary physical methods, including structural analysis using X-rays, synchrotron radiation and neutrons, optical microscopy, and atomic force microscopy. Results. Experimental data on the atomic structure, real structure, and physical properties of superprotonic crystals, including systems of hydrogen bonds and their changes, were obtained. Conclusions. The physical properties of superprotonic crystals are significantly affected by hydrogen bonding systems and their changes, primarily by the formation of dynamically disordered hydrogen bonds with energetically equivalent positions of hydrogen atoms. When carrying out diagnostics of crystalline samples, account should be taken of their real structure, including the structure of surface layers and the presence of crystallization water. These factors may affect the measured physical parameters, the boundaries of existence of phases, the formation of a multiphase state under variations in temperature.

Porous asphalt mixture performance in cold regions: Case study of Chicago

Porous Asphalt Mixtures (PAMs) improve resilience of flexible pavements in the context of climate change. PAM application in coastal cities like Chicago is of interest; however severe winters compromise the durability of PAMs given their susceptibility to freeze-thaw. This work aimed to evaluate the to-date experience with PAMs in Chicago, exploring benefits and limitations to be considered for future projects in the Southern Lake Michigan region. Full-depth PAM cores were obtained from seven sections, constructed in different years. Tests were conducted to assess the evolution of surface texture, internal structure, and multi-scale material properties. Regarding surface texture, consistent change over time was observed, such as loss of the “channel” structure, and increase in mean profile parameters because of raveling. Also, binder content varies with time within different layer depths. An aging gradient in terms of stiffness from top to bottom within the layer does not necessarily occur. However, binder ductility shows drastic and consistent reduction throughout the layer as aging increases. Analysis of internal structure using a CT scan revealed that there is also a lack of homogeneity in the air void and particle size distributions. Finally, this study suggests that full-depth PAM viscoelastic behavior is sensitive to saturation level, and this is a relevant subject to be considered, since partial saturation may be a condition often observed in the field.

A robust finite strain isogeometric solid-beam element

In this work, an efficient and robust isogeometric three-dimensional solid-beam finite element is developed for large deformations and finite rotations with merely displacements as degrees of freedom. The finite strain theory and hyperelastic constitutive models are considered and B-Spline and NURBS are employed for the finite element discretization. Similar to finite elements based on Lagrange polynomials, also NURBS-based formulations are affected by the non-physical phenomena of locking, which constrains the field variables and negatively impacts the solution accuracy and deteriorates convergence behavior. To avoid this problem within the context of a solid-beam formulation, the Assumed Natural Strain (ANS) method is applied to alleviate membrane and transversal shear locking and the Enhanced Assumed Strain (EAS) method against Poisson thickness locking. Furthermore, the Mixed Integration Point (MIP) method is used to make the formulation more efficient and robust. The proposed novel isogeometric solid-beam element is tested on several single-patch and multi-patch benchmark problems, and it is validated against classical solid finite elements and first-order Lagrange solid-beam element. The results show that the proposed formulation can alleviate the locking effects and significantly improve the performance of the isogeometric solid-beam element. With the developed element, efficient and accurate predictions of mechanical properties of lattice-based structured materials can be achieved. The proposed solid-beam element inherits both the merits of solid elements e.g. flexible boundary conditions and of the beam elements i.e. higher computational efficiency.

Conductive chitosan/polyaniline hydrogel: A gas sensor for room-temperature electrochemical hydrogen sensing

Hydrogen (H2) has been deemed a source of energy for both stationary and mobile applications to contribute to lowering carbon emissions due to its abundance (which can be extracted from various compounds), environmental friendliness, and high energy density. However, H2 gas is highly flammable and has a fast burning rate. Consequently, the need to ensure human safety and environmental preservation necessitates the development of hydrogen sensors that exhibit heightened sensitivity, a reduced detection threshold, and quick response times. Herein, we present the synthesis of a ternary hydrogel composite, chitosan-crosslinked poly(acrylic acid)-based polyaniline hydrogel (Cs-cl-pAA/PANI), which was developed to function as a cathode material in hydrogen sensing applications. The structural and optical properties of ternary cathode materials were evaluated using various analytical techniques, and hydrogen sensing was studied using electrochemical techniques. The electrochemical sensing characteristics of the hydrogel matrix were improved by including polyaniline (PANI) as a result of the overlapping of localised π-electrons in the p-orbitals. The sensitivity of the Cs-cl-pAA/PANI hydrogel was determined to be 48.7845 μA M, with a reaction time of 0.6s, recovery time of 2s, and detection limit of 3.682 μM. The sensor also exhibited outstanding restoration and repeatability.

A study on: Design and fabrication of E-glass fiber reinforced IPN composite chain plates for low duty chain drives

Chains are used in mechanical drives to carry away a large amount of load from one drive to another drive. Therefore the material of the chain should be able to withstand tensile loads and have high stiffness. Usually the chains are made up of iron. But the disadvantage is that iron consumes more weight and it is more expensive. In order overcome the difficulties, the chain plates are fabricated with the help of Interpenetrating Polymer Networks (IPNs) resins (with vinyl ester and polyurethane) and reinforced E-glass fiber composite material. The main aim of the project is to study and analyze the physical properties and structural properties of the plate material varying proportions of IPN resin such as 100% vinyl ester (VEU) with 0% polyurethane (PU), 90% VEU and 10% PU, 80% VEU and 20% PU, 70% VEU and 30% PU, 60% VEU and 40% PU. Finally a fatigue tests is conducted for different plates for different resin proportion and comparison is made between the characteristics of fabricated chain plate with that of iron material. Because of their dependability and durability, glass fibre reinforced composite link plates are used in material handling equipment, agricultural machinery, manufacturing conveyors, and automobile manufacture.

Effect of carbon quantum dots doping on structural, optical, and antibacterial properties of barium tungstate nanocomposite material

Local bacterial infection remains an increasingly severe threat to human health worldwide, and infection control is still a challenging task. Carbon Quantum Dots (CQSs) and barium tungstate show antibacterial properties. CQDs doped Barium Tungstate (BaWO4) are synthesized by using a hydrothermal route and their optical and antimicrobial activities against the Gram-positive bacteria staphylococcus aureus and optical properties were investigated. The UV–Vis reveals a shift in the bandgap from 3.62 eV to 2.93 eV due to doping of CQDs in BaWO4. The structure of the CQDs/BaWO4 were studied by XRD, which shows CQDs doped BaWO4 samples possess tetragona4 werelite structure with the preferred orientation of (112) identified by XRD at 26° having crystallite size ∼ 31 nm. Nanocomposite BaWO4/CQDs exhibit a spherical-like shape and are composed of Ba, O, W and C according to the design of the experiment. Zeta sizer of CQDs by DLS shows the size of CQDs is 7.65 nm. The FT-IR shows the presence of functional groups in doped material like CC, CO, and COOH bonds which indicate that the C-dots are functionalized with epoxy, carbonyl, hydroxyl, and carboxylic acid groups. Their elemental composition and surface morphology were studied by EDS which shows the percentage variation of CQDs in BaWO4, SEM results show the change in shape of the sample by adding CQDs to BaWO4. The TEM image proves the presence of doped material in the BaWO4. The PL spectra reveals the emission spectra shift towards a higher wavelength and absorption increases. The qualitative analysis shows the antimicrobial activity and enlargement of the inhibition zone and quantitative analysis confirms it.