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The author has recently introduced the class of CNED sets in Euclidean space, generalizing the classical notion of NED sets, and shown that they are quasiconformally removable. A set E is CNED if the conformal modulus of a curve family is not affected when one restricts to the subfamily intersecting E at countably many points. We prove that several classes of sets that were known to be removable are also CNED , including sets of σ -finite Hausdorff (n - 1) -measure and boundaries of domains with n-integrable quasihyperbolic distance. Thus, this work puts in common framework many known results on the problem of quasiconformal removability and suggests that the CNED condition should also be necessary for removability. We give a new necessary and sufficient criterion for closed sets to be (C)NED. Applying this criterion, we show that countable unions of closed (C)NED sets are (C)NED. Therefore we enlarge significantly the known classes of quasiconformally removable sets. [ABSTRACT FROM AUTHOR]

Ferroelectric polymer-based separators, known for their flexibility, ease of synthesis, and modifiability through dopants, are currently under extensive study due its potential applications in electronic devices. PVDF nanocomposites, which combine the strengths of their constituents, currently lead in emerging technologies. This research employs Zinc oxide nanoparticles (ZnO NPs) as fillers in the PVDF matrix and investigates their structural, optical, thermal and electrical properties. ZnO NPs synthesized via the combustion method, are being incorporated with varying concentrations (2, 4, 6, 8, and 10 wt%), into PVDF nanocomposite (PNC) thin films through a solution casting process. The PNC thin films are characterized using XRD, FTIR, UV–Vis spectroscopy and thermogravimetric analysis (TGA). Dielectric properties are being explored across a frequency range from 20 to 2 MHz at room temperature, revealing enhanced dielectric constants at lower frequencies, decreasing with frequency due to Maxwell–Wagner interfacial polarization. With increasing frequency, AC conductivity and electric modulus exhibit enhancement. Complex impedance analysis via the Cole–Cole plot indicates a non-Debye type of dielectric relaxation with heightened conductivity. TGA demonstrates improved thermal stability in PNC thin films. These findings suggest the potential application of the prepared PNC thin films as separators in energy storage devices. [ABSTRACT FROM AUTHOR]

Filler content in dental composites is credited for affecting its physical and mechanical properties. This study evaluated the correlation between the filler percentage and strength, modulus, shrinkage stress, depth of cure, translucency and radiopacity of commercially available high- and low-viscosity dental composites. Filler weight percentage (wt%) was determined through the burned ash technique (800 °C for 15 min). Three-point bend flexural strength and modulus were measured according to ISO 4049 with 2 mm × 2 mm × 25 mm bars. Shrinkage stress was evaluated using a universal testing machine in which composite was polymerized through two transparent acrylic rods 2 mm apart. Shrinkage was measured from the maximum force following 500 s. The translucency parameter (TP) was measured as the difference in color (ΔE00) of 1 mm thick specimens against white and black tiles. The depth of cure was measured according to ISO 4049 in a cylindrical metal mold (4 mm diameter) with a 10 s cure. Radiopacity was measured by taking a digital X-ray (70 kVp for 0.32 s at 400 mm distance) of 1 mm thick specimens and comparing the radiopacity to an aluminum step wedge using image analysis software. The correlation between the filler wt% and properties was measured by Pearson's correlation coefficient using SPSS. There was a positive linear correlation between the filler wt% and modulus (r = 0.78, p < 0.01), flexural strength (r = 0.46, p < 0.01) and radiopacity (r = 0.36, p < 0.01) and negative correlation with translucency (r = −0.29, p < 0.01). Filler wt% best predicts the modulus and strength and, to a lesser extent, the radiopacity and translucency. All but two of the high- and low-viscosity composites from the same manufacturer had statistically equivalent strengths as each other; however, the high-viscosity materials almost always had a statistically higher modulus. For two of the flowable composites measured from the same manufacturer (3M and Dentsply), there was a lower shrinkage stress in the bulk-fill version of the material but not for the other two manufacturers (Ivoclar and Tokuyama). All flowable bulk-fill composites achieved a deeper depth of cure than the flowable composite from the same manufacturer other than Omnichroma Flow Bulk. [ABSTRACT FROM AUTHOR]

Anisotropy in naturally occurring or synthetic microcellular structures is an important feature for the development of materials with high specific stiffness and strength, in addition to creating materials with unique physical properties. Polymeric foams constitute a broad class of materials that are widely used for their advantages of low density, high specific mechanical properties and high insulative properties. Traditional synthetic routes are slow, energy demanding processes that employ the use of high temperature ovens, freezers, or high‐pressure equipment. Herein we present a convenient and energy efficient method to produce anisotropic high performance polymeric foams via rapid radically induced cationic frontal polymerization coupled with chemical blowing agents. The degree of pore orientation and degree of anisotropy are a result of the propagating front working in concert with the foam volume expansion. This paper presents results into FP foam formation to illustrate how changes in boundary conditions and front initiation position affect both the microcellular structure and their resulting physical and mechanical properties. Additionally, results are presented to show how changes in resin formulation, such as the addition of nanoparticles affect both properties as well as the microcellular structure and anisotropy. [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]

We look at a momentum map associated with the Heisenberg group. We show that the cocycle associated with its momentum mapping is the value of a modulus of an associated coadjoint orbit. [ABSTRACT FROM AUTHOR]

This work investigates the AC conductivity, impedance spectroscopy, and modulus formulation of varied compositions of glass samples within the modified borovanadate glassy system, synthesized using the melt-quenching technique. Up to 10 mol% of BaO, the AC conductivity shows a rising trend as BaO content rises; however, for x = 15&20 mol%, there is a drop. The Almond West model fits the experimental data of ac conductivity and parameters such as crossover frequency, frequency exponent (s), and direct current conductivity are retrieved. All samples feature a CBH conduction mechanism at varying frequencies, except for VBa1, which has a small polaron quantum mechanical mechanism. There is good agreement in the activation energy derived from conductivity (0.565–0.742 eV), electric modulus (0.526–0.616 eV), and impedance research (0.530–0.743 eV). Dielectric studies reveal non-Debye-type behavior. According to impedance formalism, electric conduction occurs through Ba2+ ions and electron/polarons. This characteristic renders the glasses well-suited for energy storage devices. [ABSTRACT FROM AUTHOR]

Silicophosphate, prepared from Tunisian siliceous sand, has been investigated as a potential oxide ion conductor. XRD and Rietveld refinement analyses confirm the formation of pure single-phase Si5P6O25 that crystallizes in the trigonal system with R-3 space group. The electrical conductivities and dielectric properties of this material have been studied using complex impedance spectroscopy from 10 to 106 Hz at a temperature range from 600 to 680 °C. The results show that the ionic conductivity σdc increases from 5.43 × 10− 5 S.cm− 1 at 600 °C to 0.23 × 10− 3 S.cm− 1 at 680 °C with an activation energy of 1.33 eV. The frequency dependence of AC conductivity could be explained by Jonscher's power law. The dielectric constant's decrease with frequency indicates a region of dispersion resulting from a polarization process' relaxation. The simulation of the oxygen conduction using the Bond Valence Site Energy (BVSE) model shows the presence of four interstitial sites used with equilibrium sites to form a zigzag isosurface of oxygen migration. The calculated activation energy is about 1.43 eV. [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]

BaBiLaNbVO9 is a lead-free compound and has been synthesized by solid-state technique. The formation of the compound was confirmed by X-ray diffraction and is found to be crystallized in the monoclinic (space group P 21) crystal system (a = 13.7464± 0.0015 Å, b = 4.0156± 0.0012 Å, c = 12.4946 ± 0.0018 Å, β = 93.48 ± 0.01o). The crystallite size was found to be 52.91 nm. SEM and EDX studies analyzed the morphology, composition, and elemental distribution in the specimen. The average grain size is about 1.0651 μm. Several properties, such as frequency and temperature response resistivity, conductivity, and dielectric behaviours of the compound, have been analyzed. The overlapping large polaron tunnelling (OLPT) and correlated barrier hopping (CBH) models are appropriate for electrical conduction in the compound. The energy band gap (Eg) of the material was 2.40 eV, suitable for optoelectronic devices. Ferroelectric behaviour may be deduced from symmetric and well-shaped P-E hysteresis loops. The impedance study satisfies the negative temperature coefficient of resistance (NTCR) behaviour, which is suitable for thermistor devices and its correlated application. [ABSTRACT FROM AUTHOR]

Dynamic cone penetrometer (DCP) has been commonly used for the evaluation and quality control/assurance of soils before, during, and after construction in civil engineering projects. This test equipment has been increasingly used for geotechnical engineering applications but not yet been used to evaluate lightweight cellular concrete (LCC) as a backfill material. This technical note reports laboratory and field DCP tests to evaluate the properties of LCC. To establish the relationship between DCP data and other material properties, unconfined compressive strength and California bearing ratio (CBR) tests were conducted on this material. The test results showed that the measured unconfined compressive strength and CBR of LCC increased as its density increased. The DCP indices (DCPI) for the LCC specimens at different densities were almost constant with the penetration depth. This technical note proposes the correlations between the DCPI and the unconfined compressive strength and CBR, which may be used for future applications. [ABSTRACT FROM AUTHOR]

Ca and Cs doped barium titanate lead-free ceramic with the formula Ba 0.75 Ca 0.2 Cs 0.05 TiO 3 has been prepared by the solid-state reaction method. X-ray diffraction (XRD) confirms the crystallization of the sample in a tetragonal structure with a P 4 mm space group. The phase purity and grain morphology were evaluated using X-ray diffraction and scanning electron microscopy (SEM). The material exhibits a primary phase of Ba0.75Ca0.2Cs0.05TiO3 with a minor secondary phase of BaO 2 , and the average grain size is determined to be 1.66 μm. Using non-destructive complex impedance spectroscopy (CIS), we extensively studied the electrical behavior, including complex impedance (Z*), complex modulus (M*), electrical conductivity, and relaxation mechanisms, of Ba 0.75 Ca 0.2 Cs 0.05 TiO 3 over a wide temperature (85 K–290 K) and frequency range. The ac conductivity analysis reveals that the dominant conduction mechanism is the non-overlapping small polaron tunneling (NSPT) model. The impedance analysis indicates a single semi-circle in the real and imaginary parts, suggesting a single relaxation mechanism. Additionally, the activation energy was calculated to be approximately 0.0489 eV. These findings contribute to the understanding of the structural and electrical properties of Ba 0.75 Ca 0.2 Cs 0.05 TiO 3 , highlighting its potential applications in electronic devices such as capacitors, thermistors, and ferroelectric random access memories (FRAMs). [ABSTRACT FROM AUTHOR]

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]

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]

The rheological characteristics of manganese zinc (Mn-Zn) ferrite magnetic nanofluid synthesized using co-precipitation technique were examined in the absence and presence of magnetic fields. The research formulates required conditions needed for the formation of a gelly-like structure. The impact of magnetic field and temperature on the rheological properties of Mn-Zn ferrite ferrofluid is investigated. When a magnetic field was applied, higher magnetoviscoelasticity and magnetoviscosity were formed. Other rheological parameters such as damping factor which is crucial for regulating and restricting vibrations in a system was also analyzed. A stiff, gel-like structure is produced when a magnetic field is applied, and the gel-like quality grows as the magnetic field increases; when the magnetic field is removed, the gel-like and rigidity of the structure is lost. At low temperatures, the liquid phase is dominated by solid-like particles, whereas at high temperatures, the liquid-like structure is dominant. This study reveals the conditions required for the creation of high viscous effect and the viscoelastic behavior induced by the field offers important insights for optimizing the Mn-Zn ferrite ferrofluid for a range of applications. Other criterial for gel-like structure formation such as low torque and deflection angle of the ferrofluid were also established. [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]

The MCrAlY bonding layer alloy was prepared by vacuum melting, and the alloy composition was NiCoCrAlY and NiCoCrAlYHfTa. The high-temperature cyclic oxidation experiment was carried out in air at 1050∘C until it failed. The results show that Hf and Ta have a significant influence on the oxidation resistance of the alloy. The doped specimens have longer oxidation lifetimes compared to the undoped samples. The study also found that the Hf would diffuse out and combine with O to form HfO2 in the thermally grown oxide (TGO) layer, which would improve the adhesion and reduce the wrinkles of the oxide layer. Ta in the doped specimens hinders the diffusion of Al and reduces the oxidation rate, while improving the thermal mismatch. Therefore, the specimens doped with both Hf and Ta have the highest oxidation lifetimes, though the oxidation lifetime was 10 times longer than that of the undoped specimens. It is indicated that the doping of Hf and Ta is an important method to improve the oxidation lifetime of thermal barrier coatings (TBCs). [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]

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]

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]

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]

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]

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]

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]

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]

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 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]

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]

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]

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 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]

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]

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]

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]

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]

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]

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]