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For their good randomness and long iteration periods, chaotic maps have been widely used in cryptography. Recently, we have revealed the correlation between Lyapunov exponent and sequence randomness of multidimensional chaotic maps based on modular operation. Since the modular operation can realize the boundedness of chaotic state points, it is important to further reveal the deterministic correlation between Lyapunov exponent and modulus. First, we constructed an n -dimensional nondegenerate hyperchaotic map model with the desired Lyapunov exponents. Then, we gave the existence and uniqueness proof of quadrature rectangle decomposition theorem and revealed the correlation between Lyapunov exponent and modulus. The novelty lies in that (1) in order to realize the irreversibility of the iterative processes of chaotic maps, we constructed a chaotic map based on modular exponentiation, and its inverse function is the discrete logarithm problem; and (2) we reveal for the first time the correlation between Lyapunov exponent and modulus, and give the lower bound of the modulus of the nondegenerate chaotic map. In addition, to verify the effectiveness of the scheme, we constructed four-dimensional and five-dimensional chaotic maps, respectively, and analyzed their dynamical behaviors, and the results revealed that there exist linear or nonlinear correlation between Lyapunov exponent and modulus. [ABSTRACT FROM AUTHOR]

The incorporation of sugar palm fiber (SPF) into polymer composites presents an environmentally conscious and promising alternative to synthetic reinforcement materials. These composites exhibit impressive mechanical stiffness, strength, elongation, and thermal stability. Extensive research has centered on characterizing the thermal, mechanical, and physical behaviors of SPF-reinforced polymer composites under varying conditions. Despite their exceptional qualities, these composites have mainly been utilized in traditional applications such as brooms, brushes, and ropes. This study conducts a comprehensive exploration of their properties, employing dynamic mechanical analysis (DMA) to assess the thermal stability of SPF-reinforced polymer composites in both thermoplastic and thermoset matrices. The investigation focuses on critical parameters including storage modulus (E′), loss modulus (E′′), complex modulus (E), and damping factor (tan δ), with particular attention to temperature-sensitive interfacial bonds between fibers and diverse polymer matrices. Factors such as matrix type, filler type, processing and post-processing conditions, frequency, temperature, fiber length, loading, volume fraction, orientation, and treatment significantly influence the DMA properties of natural fibers. This review synthesizes the latest literature of the past decade, offering an in-depth overview of SPF polymer composites, including hybrid composites, and exploring their diverse applications. Furthermore, the study evaluates the effects of integrating synthetic fibers and employing chemical treatments on the DMA properties, impact resistance, and post-impact performance of SPF-reinforced polymer composites. By advancing knowledge in this domain, this comprehensive review provides valuable insights into designing and optimizing these composites for a wide range of engineering applications. [ABSTRACT FROM AUTHOR]

Smart wearable sensors are increasingly integrated into everyday life, interfacing with the human body to enable real-time monitoring of biological signals. This study focuses on creating high-sensitivity capacitive-type sensors by impregnating polyester-based 3D spacer fabric with a Carbon Nanotube (CNT) dispersion. The unique properties of conductive particles lead to nonlinear variations in the dielectric constant when pressure is applied, consequently affecting the gauge factor. The results reveal that while the fabric without CNT particles had a gauge factor of 1.967, the inclusion of 0.04 wt% CNT increased it significantly to 5.210. As sensor sensitivity requirements vary according to the application, identifying the necessary CNT wt% is crucial. Artificial intelligence, particularly the Multilayer Perception (MLP) model, enables nonlinear regression analysis for this purpose. The MLP model created and validated in this research showed a high correlation coefficient of 0.99564 between the model predictions and actual target values, indicating its effectiveness and reliability. [ABSTRACT FROM AUTHOR]

Hydraulic asphalt concrete is known for its excellent seepage control performance and strong deformation resistance. This engineering material has widespread applications in the seepage control structures of hydraulic buildings. Recent projects have investigated the use of acidic aggregates to improve economic efficiency. However, they have also highlighted the weaker adhesion between acidic aggregates and asphalt, which necessitates stringent construction process control. This study investigates the impact of resting conditions on the tensile properties of acidic aggregate hydraulic asphalt concrete. The results of the tensile testing indicate that the storage time significantly affects the performance of asphalt concrete. The tensile strength of the specimens without anti-stripping agents decreased from 1.711 MPa to 0.914 MPa after resting periods of 0, 10, 20, and 30 days. The specimens treated with anti-stripping agents also showed a decrease in tensile strength over time, similar to the trend observed in the previous specimens. Digital specimen simulations indicated a decrease in cohesion between the asphalt and the aggregate from 5.375 MPa to 2.664 MPa after 30 days, representing a reduction of 50.44%. To counteract the effect of the storage time on the bonding between acidic aggregates and asphalt, this study recommends reducing the grading index and maximum size of aggregates, decreasing the coarse aggregate content, and selecting smooth aggregate shapes. [ABSTRACT FROM AUTHOR]

The periodontal ligament plays a significant role in orthodontic and masticatory processes. To explicitly investigate the effects of dynamic force amplitude and frequency on the dynamic tensile properties of the periodontal ligament, in vitro tensile experiments were conducted using a dynamic mechanical analysis at various dynamic force amplitudes across a wide frequency range. Storage modulus, loss modulus, and loss factor values were measured. A Maxwell constitutive model based on modulus was established to describe the dynamic mechanical properties of the periodontal ligament. The results showed that the storage modulus ranged from 29.53 MPa to 158.24 MPa, the loss modulus ranged from 3.26 MPa to 76.16 MPa, and the loss factor values all increased with higher frequencies and higher dynamic force amplitudes. Based on the parameters obtained from the fitting results, it is evident that the short‐term response has a more pronounced impact on the elastic response of the periodontal ligament than the long‐term response. Increasing the dynamic force amplitude and its frequency amplified the viscous effects of the periodontal ligament and enhanced energy dissipation. The proposed constitutive model further demonstrated that the periodontal ligament acts as a viscoelastic biomaterial. These findings have implications for future research on the periodontal ligament. [ABSTRACT FROM AUTHOR]

AbstractPoly (N-isopropyl acrylamide) (PNIPAm) and polyacrylamide (PAAm) are widely used in antifouling research because of their non-harmful nature and their high water-absorbing capacity. In addition, hydrogels such as these two, should be investigated for their mechanical properties because their mechanical properties influence the antifouling paint containing them remaining on the surface of the vessels. In this research PAAm, PNIPAm, and kappa carrageenan (κC) doped with graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) composite gels were examined for their mechanical properties for use in antifouling paints as a potential material. For increasing the mechanical properties of composites, GO and MWCNTs are often used as doping materials. In the research described here, a compressive test was used to determine the elasticity, and the modulus was calculated. The toughness was calculated from the slope of the stress-strain curve. The PAAm, PNIPAm, and κC doped with GO and MWCNT exhibited excellent swelling and deswelling behavior and good mechanical properties as composites. The results showed that the composites’ mechanical characteristics increased with an ideal loading concentration of GO and MWCNTs. This study was inspired by our belief of a shortage of research on antifouling materials that are sensitive to the environment. We wanted to create materials that were both effective against fouling and environmentally safe by integrating the beneficial characteristics of hydrogels with potential materials inside antifouling paint. This study, we suggest, is an important step toward the development of antifouling materials with high mechanical performance that are also environmentally friendly. [ABSTRACT FROM AUTHOR]

In this work, perovskite oxide SrCeO3 was synthesized using the solution combustion method (SCM). Synthesized samples have been characterized using X‐ray diffraction (XRD), Raman, ultra violet (UV)–visible spectroscopy, and scanning electron microscopy (SEM) techniques. The XRD and Rietveld refinement has confirmed the orthorhombic structure with space group Pnma. The average grain size of this ceramic sample is 1.2 µm. The dielectric constant, dissipation factor, modulus, impedance, and alternating current (AC) and direct current (DC) conductivities were analyzed in the temperature range RT to 600°C and frequency range 20 Hz–2 MHz. Further, it was observed that the role of grain boundaries in dielectric and electrical properties is significant, at low temperatures. The origin of the dielectric relaxation and conduction process is the same. The activation energy for DC conduction (Edc) was found to be.79 eV. Electrical conduction/relaxation is assigned to the diffusion of doubly ionized oxygen (Vo··). The value of DC conductivity (1.2 × 10−3 Ω−1 cm−1 at 600°C) and activation energy of.79 eV is very close to the values reported for doped CeO2‐based oxide ion conductors for SOFCs. This study has demonstrated that SrCeO3 can be an alternative candidate for the oxide ion conductor electrolyte application and the potential to be used as a thermally stable capacitor application for microwave dielectric applications. [ABSTRACT FROM AUTHOR]

Organic‐inorganic metal halide single crystals have attracted a lot of attention due to their flexible structural design and excellent optoelectronic applications. This study details the synthesis of copper‐based [(CH3)4N]2CuBr4 hybrid metal halide single crystals via a slow evaporation method. The crystal structure, crystal habit, chemical groups, intermolecular interactions, electrical properties of the sample were studied via single crystal x‐ray diffraction, scanning electron microscopy, Raman and Fourier transform infrared spectrometer, Hirshfeld surface analysis, impedance spectroscopy, and modulus spectroscopy, respectively. An orthorhombic crystal system with the non‐centrosymmetric space group Pna21 was identified at room temperature. The deformation in the tetrahedra was calculated by the bond angle and bond length deformation index. The Cole‐Cole plot displayed the existence of depressed semicircles, which indicated the predominant distribution of grains, further confirmed by the SEM image. The deformed semi‐circular arcs on the electric modulus curve undeniably prove that the bulk effect dominates the material's electrical properties. Significantly, the compound presents a phase transition at ~240 K and excellent thermal stability up to a temperature of 400 K. Therefore, our research sheds light on the temperature dependence of electrical responses in these hybrid crystals and gives inspiration for the development of single crystal‐based efficient energy devices. [ABSTRACT FROM AUTHOR]

Aluminum (Al), poly(etheretherketone) (PEEK) thermoplastics, and their individual composites have widely been used in many industries, including aerospace and biomedical fields. However, the joining process of those composites has not been explored much to date. In this context, the friction welding process (FWP) could be used as an alternative since it has the ability to join high-strength components with minimal distortion. Therefore, the present study aimed to develop PEEK/Al nanocomposites with varying Al concentrations of 10, 20, 30, and 40 vol% using powder metallurgical technique and further joined the similar composition composites by FWP. Then, the effect of reinforced particle concentrations on the physical, morphological, structural, thermal, and micromechanical behaviors of the joined nanocomposites has been characterized by microscopy, X-ray diffraction, differential scanning calorimetry, and nanoindentation tests. The concentrations of the reinforcement were found to have a significant effect on the crystallinity, melting temperature, glass transition temperature, and thereby micromechanical properties. The results were analyzed and correlated precisely for all the welded nanocomposites systematically. The interdiffusion mechanism was found to be involved in improving the mechanical properties of the present nanocomposites. The highest elastic modulus (13.91 GPa) or nanohardness (0.31 GPa) was obtained for the rotatory part of the PEEK/Al40 nanocomposites at 80 mN load. But, the applied load of 40 mN was the best loading condition due to the uniform change in modulus and nanohardness of all the nanocomposites. Therefore, the present alternative joining method of the PEEK/Al nanocomposites might be used for aerospace components. Highlights • Development of PEEK/aluminum with 10, 20, 30 and 40 vol% Al nanocomposites. • Friction welding of similar composite material, PEEK/Al-PEEK/Al nanocomposites. • Microstructural, thermal, and nanomechanical analyses. • Effect of metal particle reinforcement on the friction welded nanocomposites. • FW PEEK/Al40 nanocomposite is found to be the best. [ABSTRACT FROM AUTHOR]

Carbonate gravelly soils are widely distributed in sub-tropical marine areas. During construction and engineering operations, carbonate gravel undergoes considerable particle crushing, which has remarkable effects on their engineering properties. A series of large-diameter oedometer tests, large-diameter drained and undrained triaxial shear tests were conducted on carbonate gravel specimens taken from the South China Sea. The carbonate gravel specimens exhibit significant particle crushing at common engineering pressure levels, and the particle crushing highly depends on the initial density, loading history and stress path. Three fragmentation modes, fracture, attrition, and abrasion, are notable in carbonate gravel specimens, which induces significant variations of PSD curves and greatly effects the mechanical properties. Particle crushing in carbonate gravel specimens increases the compressibility resulting in the compression index increases with the increase of surcharge pressure; decreases the pressure-hardening resulting in the initial Young's and secant moduli slightly increase with the increase of initial confining pressure; and decreases the dilatancy resulting in the peak and critical state friction angles significantly deceases with the increase of initial confining pressure. Particle crushing also shows great effect on the CSL of the carbonate gravel specimens in both p ′ - q space and e - p ′ space. [ABSTRACT FROM AUTHOR]

The polymer with nanoparticles tethered at each end is a unique model for unraveling the effect of chain ends on the polymer dynamics. We investigated the rheological behavior of this kind of polymer by using nonequilibrium molecular dynamics simulation. The effect of polymer lengths and nanoparticle radii on the complex moduli and viscosity was examined. The dependence of complex moduli on the frequency becomes less pronounced as the polymer is short or the nanoparticle is large. The shear thinning behavior was revealed for these systems, and the scaling exponent of complex viscosity with respect to the frequency was found to change from −1/2 to −3/4 as the polymer shortens or the nanoparticle enlarges. The rheological behavior was further explained by analyzing the mean square distance of nanoparticles. The simulation results were compared with the existing experimental finding, showing an agreement. The work provides information for understanding the chain end effect on polymer rheology. [ABSTRACT FROM AUTHOR]

To promote resourceful utilization of argon oxygen decarburization (AOD) slag, this research developed a new three-ash stabilized recycled aggregate with AOD slag, cement, fly ash (FA), and recycled aggregate (RA) as raw materials. The AOD slag was adopted as an equal mass replacement for fly ash. The application of this aggregate in a road base layer was investigated in terms of its mechanical properties and mechanistic analysis. First, based on a cement: FA ratio of 1:4, 20 sets of mixed proportion schemes were designed for four kinds of cement dosage and AOD slag replacement rates (R/%). Through compaction tests and the 7-day unconfined compressive strength test, it was found that a 3% cement dosage met the engineering requirements. Then, the unconfined compressive strength test, indirect tensile strength test, compressive rebound modulus test, and expansion rate test were carried out at different age thresholds. The results showed that the mixture's strength, modulus, and expansion rate increased initially and then stabilized with age, while the strength and modulus initially increased and then decreased with increasing R. Secondly, based on X-ray diffraction (XRD) and scanning electron microscopy (SEM) used to analyze the mechanism, it was found that the strength, modulus, and expansion rate of the new material can be promoted by blending AOD slag, due to its ability to fully stimulate the hydration reaction and pozzolanic reaction of the binder. Finally, based on the strength and modulus results, R = 3% was identified as the optimal ratio, which provides a reference point for the effective application of AOD slag and RA in road base materials. [ABSTRACT FROM AUTHOR]

It is known that if L is a Dedekind complete Riesz space and (Ω, Σ) is a measurable space, then the partially ordered linear space of all L-valued, finitely additive and order bounded vector measures m on Σ is also a Dedekind complete Riesz space (for the natural operations). In particular, the modulus |m|o of m exists in this space of measures and |m|o is given by a well known formula. Some 20 years ago L. Drewnowski and W. Wnuk asked the question (for L not Dedekind complete) if there is an m for which |m|o exists but, |m|o is not given by the usual formula? We show that such a measure m does indeed exist. [ABSTRACT FROM AUTHOR]

Highly efficient perovskite solar cells typically rely on spiro‐OMeTAD as a hole transporter, achieving a 25.7 % efficiency record. However, these cells are susceptible to harsh 85 °C conditions. Here, we present a peri‐xanthenoxanthene‐based semiconducting homopolymer (p‐TNI2) with matched energy levels and a high molecular weight, synthesized nearly quantitatively through facile oxidative polymerization. Compared to established materials, p‐TNI2 excels in hole mobility, morphology, modulus, and waterproofing. Implementing p‐TNI2 as the hole transport layer results in n‐i‐p perovskite solar cells with an initial average efficiency of 24.6 %, rivaling 24.4 % for the spiro‐OMeTAD control cells under identical conditions. Furthermore, the p‐TNI2‐based cells exhibit enhanced thermostability at 85 °C and operational robustness. [ABSTRACT FROM AUTHOR]

Highly efficient perovskite solar cells typically rely on spiro‐OMeTAD as a hole transporter, achieving a 25.7 % efficiency record. However, these cells are susceptible to harsh 85 °C conditions. Here, we present a peri‐xanthenoxanthene‐based semiconducting homopolymer (p‐TNI2) with matched energy levels and a high molecular weight, synthesized nearly quantitatively through facile oxidative polymerization. Compared to established materials, p‐TNI2 excels in hole mobility, morphology, modulus, and waterproofing. Implementing p‐TNI2 as the hole transport layer results in n‐i‐p perovskite solar cells with an initial average efficiency of 24.6 %, rivaling 24.4 % for the spiro‐OMeTAD control cells under identical conditions. Furthermore, the p‐TNI2‐based cells exhibit enhanced thermostability at 85 °C and operational robustness. [ABSTRACT FROM AUTHOR]

Polymer Nanocomposites (PNC) comprising polyvinylidene fluoride (PVDF)/Multi-walled Carbon Nanotubes (MWCNT) were studied. The structural composition and thermal stability were confirmed from XRD and DSC/TGA data, respectively. The extent of distribution of MWCNT in the PNC increases and the clustering of MWCNT also increases with an increase in the volume fraction of MWCNT ( f MWCNT ) , as confirmed by FESEM. The PNC shows an insulator-to-metal transition (IMT), with both non-universal percolation threshold (f c) of f MWCNT = 0. 0 0 6 and scaling exponents [ s = 0. 3 6 ± 0. 0 3 , s ′ = 1. 2 6 ± 0. 1 ] , respectively, attributed to adhesiveness/cold pressing and the higher aspect ratio/conductivity of MWCNT. Modulus spectroscopy confirms a non-Debye type universal relaxation behavior (β = 0. 5 4) only for the percolative sample due to Maxwell–Wagner–Sillars/interfacial polarization, while only dipolar relaxation was probed or the samples below f c . The f c with static effective dielectric constant ∼ 2 1 1 and low tan δ may be suitable for charge storage applications. [ABSTRACT FROM AUTHOR]

BaBi4Zr2Sn2O15, a modified ceramic sample belonging to the oxide family of layered ferroelectrics, is synthesized using the mixed oxide process after firing for calcination at 810 °C for 6 hrs. XRD study of the compound exhibits the growth of an orthorhombic single-phase structure at atmospheric temperature. The electrical properties of the sample are investigated in a broad temperature range (30–500 °C) and frequency range (100 Hz - 106 Hz). The dielectric properties recommend the transition from ferro to paraelectric state at 410 °C which is much more than room temperature. The impact of frequency and temperature on complex immittance parameters (impedance and modulus) are analyzed by an impedance analyzer in broad frequencies and temperature ranges. The electrical properties show; (i) the existence of semiconductor-like negative temperature coefficients of resistance behavior, (ii) evidence of electrical relaxation phenomena as a function of temperature, and (iii) the existence of single electrical relaxation ascribed to the existence of grain contribution to the electric properties. [ABSTRACT FROM AUTHOR]

Interfaces of glassy materials such as thin films, blends, and composites create strong unidirectional gradients to the local heterogeneous dynamics that can be used to elucidate the length scales and mechanisms associated with the dynamic heterogeneity of glasses. We focus on bilayer films of two different polymers with very different glass transition temperatures (Tg) where previous work has demonstrated a long-range (~200 nm) profile in local Tg(z) is established between immiscible glassy and rubbery polymer domains when the polymer-polymer interface is formed to equilibrium. Here, we demonstrate that an equally long-ranged gradient in local modulus ...(z) is established when the polymer-polymer interface (≈5 nm) is formed between domains of glassy polystyrene (PS) and rubbery poly(butadiene) (PB), consistent with previous reports of a broad Tg(z) profile in this system. A continuum physics model for the shear wave propagation caused by a quartz crystal microbalance across a PB/PS bilayer film is used to measure the viscoelastic properties of the bilayer during the evolution of the PB/PS interface showing the development of a broad gradient in local modulus ...(z) spanning ≈180 nm between the glassy and rubbery domains of PS and PB. We suggest these broad profiles in Tg(z) and ...(z) arise from a coupling of the spectrum of vibrational modes across the polymer-polymer interface as a result of acoustic impedance matching of sound waves with λ ~ 5 nm during interface broadening that can then trigger density fluctuations in the neighboring domain. [ABSTRACT FROM AUTHOR]

The microstructural evolution and Young's modulus evolution of EB-PVD TBCs upon thermal exposure and separately after CaO-MgO-Al 2 O 3 -SiO 2 (CMAS) attack have been compared and investigated. Moduli measured by four methods all show an increase due to sintering whereas their rates of increase are different. On finer scale (i.e. nano indentation), modulus increases from 87.3 GPa in as-deposited coatings to 198 GPa after sintering at 1400 °C for 100 h. While on global scale, the modulus increases from below 10 GPa to153 GPa after identical exposure. For the CMAS attacked TBCs at 1300 °C for 0.5 h, modulus values acquired by different methods are much closer. The effect of sintering and CMAS infiltration on coating's structural integrity is discussed in terms of elastic strain energy available for driving edge delamination. The energy release rate of CMAS attacked TBCs at 1300 °C for 0.5 h is ∼1200 J/m2, which is equivalent to that of TBCs exposed at 1400 °C for 250 h (no CMAS). [ABSTRACT FROM AUTHOR]

The solid-state reaction route created the lead-free dielectric material CaBiLaNbVO9 at a high temperature. The polycrystalline compound belongs to a monoclinic crystal structure having dimensions a = 10.6738 Å, b = 10.4488 Å, c = 7.1793 Å, and V = 798.04 Å3. The grain size is calculated to be 1.1029 µm. The doping of La3+ at the Bi-site and divalent cation Ca2+ substituted at site-A and Nb5+, V5+ in the site-B of ABO3 has considerably modified the structural, dielectric, and electrical conduction mechanism. The study of ac conductivity (frequency-temperature characteristics) shows CBH (correlated barrier hopping) and NSPT (non-overlapping small polaron tunneling) conduction mechanisms. Non-Debye type relaxation has been observed using impedance analysis. The modulus and impedance study have been used to confirm the short-range order of charge carriers. The average transmittance of the compound is about 82–84%, and absorption is in the range of 0.1–1.0% in the visible area applicable for transparent conductive oxide. The energy band gap is 2.73 eV. The analysis of the resistive and capacitive properties indicates the material is an electronic component for the creation of devices. [ABSTRACT FROM AUTHOR]

Third-degree burn injuries pose a significant health threat. Safer, easier-to-use, and more effective techniques are urgently needed for their treatment. We hypothesized that covalently bonded conjugates of fatty acids and tripeptides can form wound-compatible hydrogels that can accelerate healing. We first designed conjugated structures as fatty acid–aminoacid1–amonoacid2–aspartate amphiphiles (Cn acid–AA1–AA2–D), which were potentially capable of self-assembling into hydrogels according to the structure and properties of each moiety. We then generated 14 novel conjugates based on this design by using two Fmoc/tBu solid-phase peptide synthesis techniques; we verified their structures and purities through liquid chromatography with tandem mass spectrometry and nuclear magnetic resonance spectroscopy. Of them, 13 conjugates formed hydrogels at low concentrations (≥0.25% w/v), but C8 acid-ILD-NH2 showed the best hydrogelation and was investigated further. Scanning electron microscopy revealed that C8 acid-ILD-NH2 formed fibrous network structures and rapidly formed hydrogels that were stable in phosphate-buffered saline (pH 2–8, 37 °C), a typical pathophysiological condition. Injection and rheological studies revealed that the hydrogels manifested important wound treatment properties, including injectability, shear thinning, rapid re-gelation, and wound-compatible mechanics (e.g., moduli G″ and G′, ~0.5–15 kPa). The C8 acid-ILD-NH2(2) hydrogel markedly accelerated the healing of third-degree burn wounds on C57BL/6J mice. Taken together, our findings demonstrated the potential of the Cn fatty acid–AA1–AA2–D molecular template to form hydrogels capable of promoting the wound healing of third-degree burns. [ABSTRACT FROM AUTHOR]

Objectives: To compare the filler weight percentage (wt%), filler and resin composition, flexural strength, modulus, and hardness of several 3D‐printed resins to direct and indirect restorative materials. Materials and Methods: Four 3D‐printed resins (C&B MFH, Ceramic Crown, OnX, and OnX Tough), one milled resin composite (Lava Ultimate), one conventional composite (Filtek Supreme), and one ceramic (IPS e.max CAD) were evaluated. Filler wt% was determined by the burned ash technique, and filler particle morphology and composition were analyzed by scanning electron microscopy and energy‐dispersive spectroscopy, respectively. Organic resin composition was analyzed by Fourier transform infrared spectroscopy. Three‐point bend flexural strength and modulus of the materials were determined by ISO 4049 or ISO 6872. Vickers microhardness was measured. Data were compared with a one‐way analysis of variance (ANOVA) and Tukey post hoc analysis. Linear regression analysis was performed for filler wt% versus flexural strength, modulus, and hardness. Results: 3D‐printed resins were composed of various sized and shaped silica fillers and various types of methacrylate resins. Significant differences were found among filler wt% with some materials around 3% (C&B MFH), others between 33% and 38% (OnX Tough and OnX), others around 50% (Ceramic Crown), and some around 72% (Filtek Supreme and Lava Ultimate). All 3D‐printed resins had significantly lower flexural strength, modulus, and hardness than the conventional and milled resin composites and ceramic material (p < 0.001). Filler wt% demonstrated a linear relationship with modulus (p = 0.013, R2 = 0.821) and hardness (p = 0.018, R2 = 0.787) but not flexural strength (p = 0.056, R2 = 0.551). Conclusions: 3D‐printed resins contain from 3% to 50% filler content. Filler wt% alone does not affect flexural strength, but strength may be affected by resin composition as well. Although the 3D‐printed resins had lower flexural strength, modulus, and hardness than milled and conventional composite and ceramic, they demonstrated nonbrittle plastic behavior. Clinical Significance: The properties of 3D‐printed resins vary based on their composition, which affects their clinical applications. [ABSTRACT FROM AUTHOR]

As purchased, PVDF and MWCNT were used to synthesise PD by varying the volume fractions of MWCNT (fMWCNT) into the polymer matrix through the novel cold-pressing method. The structure, microstructure and the electrical properties of the samples were obtained through XRD, FESEM, and Impedance analyzer. The microstructures of the PD show the presence of two components, such as the spherulites of PVDF (retained due to the novel cold-pressing) and the distribution of MWCNT into the PVDF matrix. The extent of distribution of MWCNT in the PD increases and the clustering of MWCNT also increases with increase of fMWCNT. The PD undergo an insulator to metal transition (IMT), with a non-universal low percolation threshold (fc) value of fMWCNT = 0.006, attributed to the high aspect ratio of MWCNT and the adhesiveness/method of preparation of the PD. The scaling equations hold good in the critical region around IMT, and the non-universal critical exponents [s = 0.36 ± 0.03, s' = 1.26 ± 0.1] were obtained. Impedance, Nyquist and Modulus spectra for the PD have been implemented to understand the relaxation behaviour/microstructure of the samples. For fc, a broad relaxation, understood by a modified Kohlrausch, Williams and Watts (KWW) function, showing a non-Debye type relaxation associated with the universal stretched coefficient of β = 0.54 is obtained. The σeff with frequency obeys universal Jonscher's power law with exponent, k = 0.91 ± 0.01. [ABSTRACT FROM AUTHOR]

Optimization of energy storage performance in dielectric ceramics has been a focus in recent decades due to the benefits of high energy storage density, efficiency, and exceptional temperature stability. In this work, we report huge dielectric constant in La0.55Li0.35TiO3‐δ and sharp decrease in its value with the substitution of Sr and Cu at Ti position. These samples La0.55Li0.35TiO3‐δ (LLTO), La0.55Li0.35Ti0.9Cu0.1O3‐δ (LLTCO) and La0.55Li0.35Sr0.1Ti0.9O3‐δ (LLSTO) were prepared by solid state reaction method. The interfacial polarization of lithium ion aggregation close to the grain boundaries and the dipoles of Li ions in the sample are suggested to be the source of the enormous dielectric values. Parent composition (LLTO) shows highest dielectric constant value (6.29 × 105 at frequency 10 Hz, 7.30×104 at 1 kHz) recorded at room temperature while the lowest dielectric loss value (0.124) was observed for LLSTO at frequency 1 kHz. Structural characterization has been done using X‐ray diffraction (XRD) technique to investigate the crystal structure of the prepared compositions. The XRD patterns show the similar crystal structure for all the compositions with the parent composition LLTO. The optical band gap is calculated by Kulbeka Munk function and Tauc plot using UV–visible diffuse reflectance spectroscopy technique. The maximum band gap value (3.32 eV) is obtained for parent composition while doping of Cu and Sr at Ti site in La0.55Li0.35TiO3‐δ decreases the band gap value. Optical microscopy shows the micron size grains in these samples. Doping of Sr and Cu in perovskite structure of LLTO brings tunability in dielectric and optical properties. [ABSTRACT FROM AUTHOR]

The axial buckling load of single carbon fiber or composite strands is typically predicted using Euler's formula, developed for isotropic materials. This study introduces anisotropy in a mechanical carbon/epoxy Z‐pin model under axial pressure. It examines the influence of compressive modulus, shear modulus, off‐axis angle, and aspect ratio on its buckling behavior. Results show that the axial instability performance of the Z‐pin decreases with lower compression, shear modulus, and aspect ratio while keeping the tensile modulus fixed. Anisotropy decreases buckling load by up to 14% compared with Euler's formula, which only considers tensile modulus. Additionally, the impact of the deflection Angle between the pressure and pin‐axis can be ignored when it is less than 3°. Highlights: Euler formula overestimates composite Z‐pin buckling force under axial pressure.Anisotropy decreases buckling load by up to 14% for carbon/epoxy.Shear modulus is more influential on Z‐pin with a small aspect ratio.For off‐axial compression angles <3°, influence can be ignored. [ABSTRACT FROM AUTHOR]

Global sensitivity analysis of complex moduli of carbon fiber reinforced polymer (CFRP) is performed by using variance‐based sensitivity analysis. Twelve material properties of matrix and fiber are selected as input arguments, including fiber volume fraction, three matrix properties, and eight carbon fiber properties. Ten thousand samples are generated with Sobol sequence. Based on the correspondence principle, six complex moduli of unidirectional CFRP, and two complex moduli of quasi‐isotropic laminate, orthogonal laminate, and symmetric laminate with different fiber angles are predicted using the generalized method of cells and classical laminate theory. The sensitivity indexes of all input arguments are calculated. The results show that the loss factors of CFRP are mainly affected by the matrix loss factor and fiber axial loss factor, and slightly affected by the fiber transverse loss factor. Highlights: Sensitivity analysis reveals key factors influencing CFRP complex moduli.Impact of fiber and matrix properties on CFRP damping revealed.Insights for high‐damping and high‐stiffness CFRP development.Enhanced understanding of energy absorption mechanisms.Uncovering the dominant role of matrix and fiber axial properties in damping. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the effect of curing mode on polymerization kinetics, biaxial flexural strength (FS) and modulus (MO), and dentin bond strength (BS) of self-adhesive and conventional resin-based cements. Two materials were evaluated: one self-adhesive G-Cem LinkAce (GC) and one conventional resin cement RelyX Ultimate (RU). Polymerization kinetics was followed by infrared spectroscopy (n = 5). Disc specimens of light-activated or self-cured materials were tested for FS and MO (n = 10). Extracted human molars were divided into 4 groups (n = 10) according to resin cement, curing mode, and evaluation time (24 hs and 1 year). Composite discs were used to simulate indirect restoration which bonded to occlusal dentin with the resin cements, and light-activated or allowed to self-cure, and restored teeth were tested for microtensile BS. Data were submitted to statistical analysis at 5% significance level. A rapid rise in conversion was observed when materials were light-activated. When self-cured, RU demonstrated a slower polymerization rate and lower conversion than GC. Dual curing yielded higher FS, MO, and BS than self-curing mode to RU cement, while no significant differences were observed for GC. Light-activation influences polymerization kinetics of resin-based cement, but it did not influence the mechanical properties and adhesion of the self-adhesive cement tested (GC). [ABSTRACT FROM AUTHOR]

As wind turbine power requirements have evolved from the order of kilowatts (kWs) to the order of several megawatts (MWs), wind turbine components have been subjected to more demanding and critical operating conditions. The wind turbine must cope with higher wind loads due to larger blade sizes, which are also time-varying, and, ultimately, higher power levels. One of the challenges in the manufacture of high-power wind turbines lies in the gearbox and consists of achieving ever-greater power density without compromising efficiency, i.e., greater load capacity with lower weight (and production cost) and reduced power losses. Epicyclic geartrains are used to build the gearbox due to various advantages in relation to conventional gear systems, such as higher feasible gear ratios, higher efficiency, compactnesss, and lower weight. In this paper, several epicyclic geartrains with different structures will be analysed to reveal the influence that certain design parameters have on the size and weight of the gearbox components in the selected model and, therefore, of the gearbox itself. For this purpose, the theoretical model of the gearbox will be planned and the influence of the calculation parameters on the gearbox design will be analyzed following ISO 6336. Special emphasis is placed on the influence of the material used; the modulus and tooth width on the size and weight of the gearbox will be observed. Critical stresses are also calculated. The goal is to prepare the theoretical basis for an optimization process subject to geometric, kinematic, and dynamic constraints that will result in a gearbox as compact, energy-dense, and light as possible without compromising the service life of the components. [ABSTRACT FROM AUTHOR]

The extraordinary physical characteristics and enormous potential for technological applications of multiferroic materials have sparked recent interest in these materials. In this work, the composition of aliovalent ions Ba2+/Ti4+ doped YMnO3 i.e., Y0.95Ba0.05Mn0.95Ti0.05O3 ceramic sample was prepared through the solid-state method. The structural, dielectric, and ferroelectric properties of the prepared sample were studied in detail. X-ray diffraction patterns unveil the hexagonal crystal structure of the ceramic owning P63cm space group symmetry, which is also authenticated by accomplishing Rietveld's refinement of the sample. Nevertheless, the ceramic demonstrated the emergence of the orthorhombic peak. The formation of phase composition of the prepared sample was proved through FT-IR spectroscopic measurement. The Raman spectroscopy analysis of the sample reveals the presence of subtle vibrational modes. The investigation of the dielectric and electrical properties of the prepared sample at frequencies between 1 kHz and 1 MHz and temperatures spanning from 303 to 623 K has yielded significant outcomes. These outcomes include dielectric dispersion, conduction mechanism, and relaxation process of the samples, which are highlighted in this study. The ferroelectric behaviour of the prepared sample has been studied using PE hysteresis loop measurement. [ABSTRACT FROM AUTHOR]

The falling weight deflectometer (FWD) test is a common non-destructive testing method for evaluating the structural capacity of pavements. At present, data processing of the FWD test mainly focuses on the deflection data, while paying less attention to the deflection-time history. Because a FWD is equipped with impulse loads and geophones, which allow for the generation and capture of surface wave signal propagation, it is hypothesized that Rayleigh wave dispersion theory can be applied to calculate the modulus profile along the pavement depth by analysing the dispersive properties of the deflection signal measured during FWD tests. To test this hypothesis, we develop a new methodology for the FWD test and data analysis, referred to as the FWD dispersion curve method. We first introduce the concept of the new method, followed by an illustration of the procedure and the experimental set-up. Case studies on three concrete pavement segments are then presented to evaluate the effectiveness of the FWD dispersion curve method. Modifications to the existing FWD device are further recommended for the impact loading sources and signal collection process so that the modulus of a much shallower layer, such as the concrete slab and upper asphalt layers, can be obtained. This article is part of the theme issue 'Artificial intelligence in failure analysis of transportation infrastructure and materials'. [ABSTRACT FROM AUTHOR]

The effect of frequency and temperature on the permittivity and transport properties of calcium manganese was investigated. The sample was synthesized using a simple, an economic and a reproducible complex polymerizable route. Thereafter, it was characterized by the X-ray diffraction and complex impedance spectroscopy techniques. The obtained results showed that CaMnO3–δ exhibits a semiconducting behaviour between room temperature and 400°C. Beyond that temperature, the perovskite behaves as a metal. As for the activation energy, it showed a change around 400°C, which is attributed to the first-order transition from semiconducting to the metallic behaviour. Moreover, the dielectric constant and the loss exhibited a decreasing trend with increasing frequency, which is a characteristic of polar dielectrics. Between 25 and 400°C, the maximum barrier height increased from 0.1 to 0.32 eV. The low dissipation factor at high frequencies seems to be an interesting feature highlighting the promising use of CaMnO3–δ in high-frequency microwave device applications. [ABSTRACT FROM AUTHOR]

Generally, the dynamic modulus and bending stiffness modulus are used to evaluate the mechanical properties of asphalt mixture, and they are also used as basic parameters for asphalt mixture design. Therefore, a study was conducted on changes in the dynamic modulus and bending stiffness modulus of hot-recycled asphalt mixture with high levels of reclaimed asphalt pavement (RAP) under the influence of different factors: dosage of regenerant, curing temperature, and curing time. The performance of reclaimed asphalt pavement (RAP) was first evaluated. Then, the hot-recycled asphalt mixture was adjusted and designed in order to conduct modulus experiments, composed of the dynamic modulus test and three-point bending test. Finally, the influencing factors were not only qualitatively but also quantitatively analyzed to clarify the change laws of the mechanical parameters of hot-recycled asphalt mixture. The results showed that the modulus of the recycled asphalt mixture first decreased, then increased, and then decreased with increasing dosage of regenerant. As the curing time or temperature increased, the modulus first decreased and then increased. In terms of the dynamic modulus of the hot-recycled asphalt mixture, the curing time had the greatest impact, followed by dosage of the regenerant and curing temperature. For bending stiffness modulus, the influence of dosage of the regenerant was the greatest, followed by curing time and curing temperature. For the bending stiffness modulus of hot-recycled asphalt mixture, the curing conditions had a greater influence compared with the dynamic modulus. [ABSTRACT FROM AUTHOR]

A novel fitting method of obtaining the anisotropic complex moduli of fibers based on the complex moduli of matrix and composites is presented. The complex longitudinal, transverse and in‐plane shear moduli of the unidirectional T700 carbon fiber reinforced epoxy resin composite and the complex modulus of its matrix are measured using dynamic mechanical analysis. The predicted properties of the composite are calculated using the generalized method of cells (GMC). The complex axial, transverse and axial shear moduli of the carbon fibers are obtained by minimizing the sum of the squares of the modules of the difference between the test properties and predicted properties. Finally, the results of the experiment, finite element analysis, and GMC are compared. The results show that the complex axial and transverse moduli of the carbon fibers can be accurately evaluated, while the complex axial shear modulus cannot be accurately determined. [ABSTRACT FROM AUTHOR]

Density-modulus relationships are necessary to develop finite element models of bones that may be used to evaluate local tissue response to different physical activities. It is unknown if juvenile equine trabecular bone may be described by the same density-modulus as adult equine bone, and how the density-modulus relationship varies with anatomical location and loading direction. To answer these questions, trabecular bone cores from the third metacarpal (MC3) and proximal phalanx (P1) bones of juvenile horses (age <1 yr) were machined in the longitudinal (n = 134) and transverse (n = 90) directions and mechanically tested in compression. Elastic modulus was related to apparent computed tomography density of each sample using power law regressions. We found that density-modulus relationships for juvenile equine trabecular bone were significantly different for each anatomical location (MC3 versus P1) and orientation (longitudinal versus transverse). Use of the incorrect density-modulus relationship resulted in increased root mean squared percent error of the modulus prediction by 8-17%. When our juvenile density-modulus relationship was compared to one of an equivalent location in adult horses, the adult relationship resulted in an approximately 80% increase in error of the modulus prediction. Moving forward, more accurate models of young bone can be developed and used to evaluate potential exercise regimens designed to encourage bone adaptation. [ABSTRACT FROM AUTHOR]

The current work is focused on numerical and experimental studies of woven fabric composites modified by hybridisation with biological (cellulosic) filler materials. The mechanical performance of the composites is characterized under tensile, bending and impact loads and the effect of hybridisation is observed with respect to pure and nonhybrid composites. Numerical models are developed using computational tools to predict mechanical performance under tensile loading. The computational prediction results are compared and validated with relevant experimental results. This research is aimed at understanding the mechanical performance of basalt–epoxy composites partially reinforced with micro-/nano-sized bio-fillers from cellulose and intended for various application areas. Different weave structures, e.g., plain, twill, matt, etc., were investigated with respect to the mechanical properties of the hybrid composites. The effects of hybridizing with cellulose particles and different weave patterns of the basalt fabric are studied. In general, the use of high-strength fibres such as basalt along with cellulosic fillers representing up to 3% of the total weight improves the mechanical performance of the hybrid structures. The thermomechanical performance of the hybrid composites improved significantly by using basalt fabric as well as by addition of 3% weight of cellulosic fillers. Results reveal the advantages of hybridisation and the inclusion of natural cellulosic fillers in the hybrid composite structures. The material developed is suitable for high-end applications in components for construction that demand advanced mechanical and thermomechanical performance. Furthermore, the inclusion of biodegradable fillers fulfills the objectives of sustainable and ecological construction materials. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles of NiFe2O4 were successfully prepared by utilizing the sol–gel techniques. The prepared samples were investigated through various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), dielectric spectroscopy, DC magnetization and electrochemical measurements. XRD data analysed using Rietveld refinement procedure inferred that NiFe2O4 nanoparticles displayed a single-phase nature with face-centred cubic crystallinity with space group Fd-3m. Average crystallite size estimated using the XRD patterns was observed to be ~10 nm. The ring pattern observed in the selected area electron diffraction pattern (SAED) also confirmed the single-phase formation in NiFe2O4 nanoparticles. TEM micrographs confirmed the uniformly distributed nanoparticles with spherical shape and an average particle size of 9.7 nm. Raman spectroscopy showed characteristic bands corresponding to NiFe2O4 with a shift of the A1g mode, which may be due to possible development of oxygen vacancies. Dielectric constant, measured at different temperatures, increased with temperature and decreased with increase in frequency at all temperatures. The Havrilliak–Negami model used to study the dielectric spectroscopy indicated that a NiFe2O4 nanoparticles display non-Debye type relaxation. Jonscher's power law was utilized for the calculation of the exponent and DC conductivity. The exponent values clearly demonstrated the non-ohmic behaviour of NiFe2O4 nanoparticles. The dielectric constant of the nanoparticles was found to be >300, showing a normal dispersive behaviour. AC conductivity showed an increase with the rise in temperature with the highest value of 3.4 × 10−9 S/cm at 323 K. The M-H curves revealed the ferromagnetic behaviour of a NiFe2O4 nanoparticle. The ZFC and FC studies suggested a blocking temperature of ~64 K. The saturation of magnetization determined using the law of approach to saturation was ~61.4 emu/g at 10 K, corresponding to the magnetic anisotropy ~2.9 × 104 erg/cm3. Electrochemical studies showed that a specific capacitance of ~600 F g−1 was observed from the cyclic voltammetry and galvanostatic charge–discharge, which suggested its utilization as a potential electrode for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Coatings with tunable refractive index and high mechanical resilience are useful in optical systems. In this work, thin films of HfO2 doped with Al2O3 were deposited on silicon at 300 °C by using plasma-enhanced atomic layer deposition (PE-ALD). The mainly amorphous 60–80 nm thick films consisted Al in the range of 2 to 26 at.%. The refractive indexes varied from 1.69 to 2.08 at the wavelength of 632 nm, and they consistently depended on the composition. The differences were higher in the UV spectral region. At the same time, the hardness of the films was from 12–15 GPa; the modulus was in the range of 160–180 GPa; and the mechanical properties did not have a good correlation with the deposited compositions. The deposition conditions, element contents, and refractive indexes at respective wavelengths were correlated. The results indicated that it is possible to tune optical properties and retain mechanical properties of atomic layer-deposited thin films of HfO2 with Al2O3 as doping oxide. Such films could be used as mechanically resilient and optically tunable coatings in, for instance, micro- or nano-electromechanical systems or transparent displays. [ABSTRACT FROM AUTHOR]

In this study, the impact of Nd doping on the structural, microstructural, dielectric, ferroelectric, and transport properties of Pb (1 - x) Nd x (Fe 0.5 Nb 0.5) 1 - x / 4 O 3 (PNFN) solid solutions ( x = 0 , 0.02 , 0.04 , 0.08 , and 0.1 ) is reported. For all the solid solutions, room temperature Rietveld refined X-ray diffraction (XRD) analysis reveals the monoclinic crystal structure with Cm space group. From Field emission scanning electron microscope (FESEM) studies, the polyhedral-shaped grains are found to be homogeneously distributed. Variation of dielectric properties with temperature displays the decrease of phase transition temperature (TC) with increasing Nd content. The temperature-dependent AC conductivity follows the Arrhenius behavior and the activation energies are calculated for high temperature regions. The frequency dependent AC conductivity behavior obeys the Johnscher's power law. Impedance spectroscopy results show the impact of conductivity from the bulk (grain) and displays non-Debye type of behaviour. Electric modulus demonstrates thermally activated relaxation phenomenon in the materials. Polarization vs. electric field (P-E) loops analysis confirms the ferroelectric nature of the materials. With increase in Nd concentrations, the value of remanent polarization (2Pr) increases, on the other hand, the coercive field (2Ec) value decreases. Both of these properties are suitable for enhancement of the physical properties of the multiferroic materials. [ABSTRACT FROM AUTHOR]

It is extremely important to investigate the mechanical properties and failure characteristics of granite at the mesoscale to understand the mesoscopic evolution mechanism of the time-dependent fracture of deep-buried hard rocks. This study explores the mesoscopic mechanical properties (i.e., hardness, Young's modulus, and fracture toughness) of the primary granite minerals and their interfaces using nanoindentation. Micro X-ray computed tomography was used to analyze the fracture characteristics of the failed Brazilian disc of granite. Moreover, two homogenization upscaling methods were used to calculate granite's Young's modulus and compared with that from uniaxial compression test results. The results demonstrate the following: (1) The mechanical properties of granite minerals are related to the peak load of nanoindentation. Young's modulus and hardness of quartz, K-feldspar, and plagioclase decrease with an increase in the peak load and tend to be stable when the peak load reaches 5000 μN, whereas Young's modulus and hardness of biotite at multiple peak loads are in variability and irregularity. (2) Young's modulus and hardness of quartz–plagioclase and quartz–biotite interfaces are between quartz and plagioclase and quartz and biotite, respectively. Furthermore, a linear formula is proposed to estimate fracture toughness based on Young's modulus of granite minerals. (3) The generalized means method that predicts granite's Young's modulus is more accurate compared to the Mori–Tanaka method. (4) Under Brazilian splitting conditions, ~ 84% of tensile cracks along intragranular cracks primarily occur in feldspar minerals, while ~ 16% along grain boundaries occur at feldspar–biotite interfaces. Highlights: Mesomechanical properties of granite minerals and mineral interfaces. A linear relationship between the fracture toughness and Young's modulus. Homogenization methods used for upscaling the mesoscopic Young's modulus of granite. [ABSTRACT FROM AUTHOR]

Information on mechanical properties of human enamel and dentin and effect of load on their deformation and damage tolerance is very important in the development of successful dental materials. In this study, the hardness, indentation modulus and deformation characteristics of tooth have been investigated across the lingual–buccal enamel and dentin cross‐section by instrumented indentation up to 1500‐nm indentation depth. We realized and examined the distribution of hardness and modulus at different areas of enamel and dentin with the aim to understand deformation behaviour at these different locations. Scanning electron microscopy was used for the microstructure characterization of the enamel and dentin and their deformation behaviour. Raman spectroscopy analyses were carried out for determination of the enamel and dentin composition as well. The average values of hardness and modulus for enamel in the occlusal area are 5.35 ± 0.19 and 98.1 ± 1.5 GPa, in the inner area 3.68 ± 0.5 and 81.8 ± 5 GPa and in the area close to the dentin–enamel junction 2.83 ± 0.27 and 71.4 ± 4.1 GPa, respectively. The average values of hardness and modulus of dentin in the area close to the dentin–enamel junction are 0.71 ± 0.05 and 21.27 ± 0.76 GPa and in the inner area 0.65 ± 0.06 and 19.79 ± 0.93 GPa, respectively. The effect of the indentation location on deformation and mechanical properties was clarified. [ABSTRACT FROM AUTHOR]

Structural coloring of dental resin-based composites (RBC) is used to create universal chromatic materials designed to meet any aesthetic need, replacing the mixing and matching of multiple shades. The microstructural adjustments to create this desideratum involve nanoscale organic–inorganic core–shell structures with a particular arrangement. The generally higher polymer content associated with these structures compared to universal chromatic RBCs colored by pigments, which in their microstructure come close to regularly shaded RBCs, can influence the way the material ages. Accelerated and slow aging up to 1.2 years of immersion in artificial saliva at 37 °C were therefore compared in relation to their effects on the materials described above and in relation to the immersion conditions prescribed by standards. Quasi-static and viscoelastic parameters were assessed to quantify these effects by a depth-sensing indentation test equipped with a DMA module. The microstructure of the materials was characterized by scanning electron microscopy. The results convincingly show a differentiated influence of the aging protocol on the measured properties, which was more sensitively reflected in the viscoelastic behavior. Accelerated aging, previously associated with the clinical behavior of RBCs, shows a 2- to 10-fold greater effect compared to slow aging in artificial saliva of up to 1.2 years, highly dependent on the microstructure of the material. [ABSTRACT FROM AUTHOR]

This study developed polypropylene (PP) nanocomposites containing surface-functionalized boron nitride (BN) decorated with BaTiO3 (BT). The developed nanocomposites showed well-dispersed nanoparticles in the PP matrix. The nanocomposites showed optimal hardness, elastic modulus, and stiffness of about 166.6 MPa, 2.7 GPa, and 0.12 mN/nm for PP/15BN-5BT nanocomposite compared to 79.4 MPa, 1.7 GPa, and 0.089 mN/nm measured for the pure PP, which are increments of about 110%, 59%, and 35% respectively. Heat deflection temperature and dynamic mechanical properties were also enhanced. Therefore, this study discussed the effects of BN decorated with BT on the nanomechanical and thermomechanical properties of PP nanocomposites. [ABSTRACT FROM AUTHOR]

In this research, it was explored how the strength of sand core would be affected by the silicate binder with varying modulus and different cation types (Na and K) and micro-silica powder. To be specific, the microscopic morphology of the bonding bridge was examined by scanning electron microscope (SEM), while the changes in internal structure were revealed through Fourier transform infrared spectrum (FT-IR) analysis. It was discovered that with the modulus reduced from 2.3 to 1.3, there was a progressive increase from 20% to 50% in the amount of micro-silica powder as required for the sand cores to reach the maximum bonded strengths. Under the same conditions, the strength of sand cores bonded by potassium silicate was improved compared to sodium silicate. According to FT-IR analysis, the decline in modulus improved not only the concentration of OH– but also the density of active groups inside silicate solution, which is conducive to the formation of Si–O–Si bonds through reaction with micro-silica powder. Meanwhile, the results of the EDS and FT-IR analysis suggest a higher concentration of Si–O–Si bonds in the mixture of potassium silicate and micro-silica powder. Consequently, the sand core bonded by potassium silicate outperformed that with sodium silicate in both tensile strength and storage performance. [ABSTRACT FROM AUTHOR]

Polyacrylamide nanospheres are a kind of polymer material that can improve the development effect of oilfield water flooding and realize reservoir stimulation. However, due to its good water absorption, the strength cannot well meet the needs of practical production, and is forced to be limited to application on oil displacement. Therefore, in this paper, SiO2/PAM composite nanospheres were synthesized by the inverse microemulsion method to meet the needs of profile control and water shutoff in oilfields. The structure, oil displacement effect and rheological properties of polyacrylamide nanospheres and SiO2/PAM composite nanospheres were comparatively studied. The results show that both nanospheres are viscoelastic nanospheres. Since the elastic response is greater than the viscous response in SiO2/PAM composite nanospheres, and the polymer nanospheres do the opposite, there are significant differences in various rheological properties, such as variation of apparent viscosity with shear rate, creep recovery characteristics, viscoelasticity etc. This work provides a basis for the practical application of SiO2/PAM composite nanospheres in oilfields. [ABSTRACT FROM AUTHOR]

Cobalt sulphides, including CoS, CoS2, Co3S4 and Co9S8, have been studied as potential anode materials for Li- and Na-ion batteries. However, the mechanical properties of the cobalt sulphides have not been intensively investigated. In this work, density functional theory (DFT) calculation was employed to study the mechanical properties of the cobalt sulphides mentioned above. Besides, the mechanical properties of final products of lithiation/sodiation of Co9S8 have been calculated, including the bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio. This work provides an insight into understanding the electrochemical performance of Co9S8 material as anode material for Li- and Na-storage during the cycling process. [ABSTRACT FROM AUTHOR]

Polymeric hydrogels have drawn considerable attention as a biomedical material for their unique mechanical and chemical properties, which are very similar to natural tissues. Among the conventional hydrogel materials, self-healing hydrogels (SHH) are showing their promise in biomedical applications in tissue engineering, wound healing, and drug delivery. Additionally, their responses can be controlled via external stimuli (e.g., pH, temperature, pressure, or radiation). Identifying a suitable combination of viscous and elastic materials, lipophilicity and biocompatibility are crucial challenges in the development of SHH. Furthermore, the trade-off relation between the healing performance and the mechanical toughness also limits their real-time applications. Additionally, short-term and long-term effects of many SHH in the in vivo model are yet to be reported. This review will discuss the mechanism of various SHH, their recent advancements, and their challenges in tissue engineering, wound healing, and drug delivery. [ABSTRACT FROM AUTHOR]

In this work, Gd2O3 bulks were sintered at temperatures ranging from 1400 °C to 1600 °C for times from 6 h to 24 h, and their microstructure and properties were studied for a wider application of materials in thermal barrier coatings. The densification of the Gd2O3 bulk reached 96.16% when it was sintered at 1600 °C for 24 h. The elastic modulus, hardness, fracture toughness and thermal conductivity of the bulks all increased with the rise in sintering temperature and extension of sintering time, while the coefficient of thermal expansion decreased. When the Gd2O3 bulk was sintered at 1600 °C for 24 h, it had the greatest elastic modulus, hardness, fracture toughness and thermal conductivity of 201.15 GPa, 9.13 GPa, 15.03 MPa·m0.5 and 2.75 W/(m·k) (at 1100 °C), respectively, as well as the smallest thermal expansion coefficients of 6.69 × 10−6/°C (at 1100 °C). [ABSTRACT FROM AUTHOR]

The melt-quenching technique was used to synthesize tellurite glasses of the chemical composition 80TeO2-(20-x) ZnO-xV2O5. X-ray diffraction (XRD) patterns indicate the amorphous nature of the prepared glasses. Raman and FTIR measurements demonstrate a progressive substitution of the Te-O-Te linkages by the Te-O-V bridges and the formation of VO4 and VO5 units by a change of the vanadium coordination due to the higher number of oxygens incorporated by further addition of V2O5. The AC conductivity was investigated in the frequency range of 40 Hz to 107 Hz between 473 K to 573 K. A good coherence of the AC conductivity was found using a model correlating the barrier hopping (CPH) and the dominant conduction process changes from ionic to polaronic with the addition of V2O5. The dielectric constant exhibits high values in the range of lower and medium frequencies. Both variations of the electric modulus and the dielectric loss parameters with frequency and temperature showed a relaxation character mainly assigned to the vanadate phases. The electric modulus displays a non-Debye dielectric dispersion and a relaxation process. The present results open the door to future zinc-tellurite glasses-doped vanadium exploitation as a potential electrolyte-based material for solid-state batteries. [ABSTRACT FROM AUTHOR]

Most commercially-available mechanical testing devices are bulky, expensive, and unable to evaluate changes in sample microstructure under load. This leaves a crucial gap in understanding between material structure and bulk mechanical properties. Our objective was to fabricate a mechanical testing device small enough to fit in most upright or inverted microscopy stages and able to position samples to allow for simultaneous mechanical and microstructural characterization. Parts were 3D printed using the hobbyist-friendly Fused Filament Fabrication technique, then assembled with commercial fasteners and translation components to create a mechanical testing device that utilized the deflection of plastic posts to determine sample reaction forces under applied strain. Video of sample deformation was analyzed using a custom processing script to calculate stress and strain behavior in an automated and high-throughput manner. This device was able to perform mechanical characterization with an accuracy comparable to commercial mechanical testing devices for a wide range of nonlinear and viscoelastic samples under dry and hydrated conditions. Additionally, the device showed compatibility with different upright and inverted microscopes and was able to demonstrate accurate mechanical testing results when used with these instruments. We successfully developed a device capable of accurately testing a majority of soft materials in the field of Biomedical Engineering with the ability to perform additional microstructural characterization using microscopy at a price point of $600. [ABSTRACT FROM AUTHOR]

Ramie fiber as the longest natural cellulose fiber in the world has been widely used in textile production. However, the rigidity of ramie fiber greatly restricts its application in high value-added garments. The softening treatment of ramie fibers is therefore essential. In this study, four different concentrations of ionic liquid (IL) solutions, [Emim]OAc(1-ethyl-3-methylimidazolium acetate), were used to treat degummed ramie fibers. The fiber fineness, mechanical properties, moisture absorption, and liberation ability were tested, and the fibers were also examined with Scanning Electron Micorscope (SEM), Gel Permeation (GPC), and X-ray diffraction (XRD). The results showed that the fiber modulus after 90% IL treatment was decreased to 31% of its original value while the breaking tenacity was decreased to 50% of its original value, these mechanical properties of treated ramie fiber were similar to cotton fiber and much softer than regular ramie fibers. Moreover, with the IL treatment, the ramie fiber presented higher water absorption and breaking elongation. It is believed that with the proper IL treatment, the ramie fiber will show better potential for textile production. [ABSTRACT FROM AUTHOR]