Search

Abstract2H diamond (lonsdaleite) is a promising material for contemporary science. However, there is still no well documented experimental or theoretical work for 2H diamond at high temperatures. Therefore, this work is the first theoretical contribution for the titled features of 2H diamond. The elastic constants decline with rising temperature and conform the Born stability. Both Pugh ratio and Poisson’s ratio results indicate the brittle character of 2H diamond. Both monotonic and non-monotonic hardness behavior with a notable elastic anisotropy were obtained and discussed. Presented results of this work for 2H diamond aligns well with available literature of other 2H materials. [ABSTRACT FROM AUTHOR]

Micrometer‐sized monodisperse silicone droplets are prepared through a sol–gel process involving 3‐methacryloxypropylmethyldimethoxysilane (MPDS) at room temperature for 1.5 h in the presence of NH3 as a catalyst. The size of the obtained droplets is controlled by changing the stabilizer concentration and solvent polarity. However, the obtained droplets have not maintained their particulate shape in the dry state due to the absence of a cross‐linking structure. Thus, radical polymerization is performed on the obtained silicone droplets at 70 °C for 2 h; consequently, spherical particles with high monodispersity are observed in the dry state, indicating the presence of a cross‐linked structure. Microcompression tests are conducted to evaluate the mechanical properties of the silicone particles. Initially, the recovery ratio (elasticity) is not high because the molecular weight of the silicone particles is low, ≈600, due to MPDS cyclization (MPDS trimer). Anionic ring‐opening polymerization is therefore performed to extend the molecular weight of the MPDS trimer. Benzyldodecyldimethylammonium bromide and tetrakis[tris(dimethylamino)phosphoranylidenamino]phosphonium chloride are used as catalysts for anionic ring‐opening polymerization. These catalysts increased the molecular weight to ≈2000 and 7600, respectively. Furthermore, the silicone particles obtained through anion ring‐opening polymerization and radical polymerization have high recovery ratios (elasticity). [ABSTRACT FROM AUTHOR]

Purpose: The vibration characteristics of an isotropic and homogeneous elastic hollow cylinder with double porosity, emphasizing the influence of the magnetic field in the context of nonlocal elasticity, are investigated. The constitutive relations and governing equations are described in the radial direction. Methods: A technique of time-harmonic vibration is implemented to derive a set of ordinary differential equations from the governing equations. The frequency equation for the vibration continuation is established under the conditions of traction-free boundary conditions. MATLAB software is employed with a numerical iteration method to explore free vibration analysis. Results: Analytical results have been authenticated with Computer-simulated numerical results and are presented through graphical representations illustrating the frequency shift for both the nonlocal and local elastic cylinders with double porous structures under the influence of a magnetic field. Conclusion: Numerically simulated data are tabulated to depict natural frequencies as a function of the mode numbers. The distinct behaviors associated with specific modes and the tendency towards linearity as the mode numbers increase highlight the intricate interaction between the magnetic field and the dynamic attributes of the system. [ABSTRACT FROM AUTHOR]

For the first time, a theoretical investigation has been conducted into the structural, electrical, elastic, and optical properties of innovative bismuth-layered structure ferroelectric (BLSF) materials XTi4Bi4O15 (where X = Sr, Ba, Be, and Mg). For all of the calculations, PBE-GGA and the ultra-soft pseudopotential plane wave techniques have been implemented with the DFT-based CASTEP simulation tool. Based on the exchange correlation approximation, the calculations reveal that XTi4Bi4O15 (X = Sr, Ba, Be, and Mg) materials demonstrate direct band-gap semiconductor behavior with an estimated density functional fundamental gap in the range from 1.966 eV to 2.532 eV. The optical properties of these materials exhibit strong absorption and low reflection in the visible range. Moreover, the estimations of the elastic properties of the materials have shown mechanical stability and ductile behavior (due to B/G > 1.75), where G and B denote the shear modulus and the bulk modulus. Based on the above-mentioned highlights, it can be confidently stated that these materials are promising potential candidates for photovoltaic applications and solar cells due to their suitable direct band gap and high absorption coefficient. [ABSTRACT FROM AUTHOR]

Background/aim: This study aims to compare the success rates of rigid registration (RR) and elastic registration (ER) systems in diagnosing all cancers and clinically significant prostate cancer (csPC) in software-based targeted prostate biopsies (TPBs) by performing matching analysis. Materials and methods: The data of 2061 patients from six centers where software-based TPB is performed were used. All cancer and csPC detection rates of the RR and ER systems were compared following Mahalanobis distance matching with the propensity score caliper method. Logistic regression analysis was applied to identify factors predicting clinically insignificant prostate cancer (ciPC) and csPC diagnoses. Additionally, the International Society of Urological Pathology Grade Group (ISUP GG) upgrade rates of RR and ER systems were compared between biopsy and radical prostatectomy pathologies. Results: The matched sample included 157 RR and 157 ER patients. No statistically significant difference was found between ER and RR in terms of csPC detection rate (28.0% vs. 22.3% respectively, p = 0.242). The detection rate of all cancers by ER compared to RR was found to be significantly higher (54.8% vs. 35.7% respectively p < 0.001,). No statistically significant difference was found between the ER and RR groups regarding pathological upgrade (39.7% vs. 24.2% respectively, p = 0.130). In the logistic regression analysis performed to determine the factors predicting ciPC, decreased prostate volume and ER system use were found to be independent predictive factors. Conclusion: While the detection rate of csPC was similar for the RR and ER systems, the detection rate of all cancers and ciPC was significantly higher with the ER systems. [ABSTRACT FROM AUTHOR]

Determining the mechanical characteristics of the artery is very essential for the production of vascular implants. In the present work, the mechanical characteristics of arterial walls were investigated by considering plaque and stent in a 3D model. This article aims to investigate the effect of the arterial tissue with the same boundary conditions and restrictions for an artery blocked with the plaque and stent, in creating stress in the tissue. An intravascular stent implantation is a treatment method whose success largely depends on the mechanical characteristics of each vascular component, plaque and stent, and blood flow pressure. For opening up the blood flow in the blocked artery, stents could be used as medical devices. In this research, a stent was designed, and its impact on all three models of elastic, viscoelastic, and hyper-elastic arterial tissue with plaque was studied and compared. An ideal finite element model was made to find the effect of three types of the artery tissue (elastic, viscoelastic, hyper-elastic) with the systolic and diastolic blood flow pressure to observe the stress and the deformation of arteries, plaques, and stents. In addition, for the hyper-elastic model, two Mooney-Rivlin and Ogden models were also investigated. It was found that the type of artery had an effective impact on the result of the stress and the deformation created in the stented artery. Moreover, the results illustrated that considering different models for the artery tissue affected the plaque and stent behavior. Arteries exhibit interesting mechanical behaviors. In the present study, an attempt was made to investigate different mechanical behaviors of arteries with the plaque and stent obstruction. In the examined models, the stress for the artery and plaque was higher in the Ogden model and the lowest one was in the viscoelastic model, and the deformation was higher in the viscoelastic model and lower in the Ogden model. It should be noted that the average stress for the vessel in the Ogden model was about 50% higher than the viscoelastic model. Pathological changes in the walls of the vessels can lead to high-risk cardiovascular diseases such as heart attacks and strokes. Understanding arterial mechanical behaviors provides valuable insight into disease. Therefore, the investigation of different behavioral models helps to evaluate the behavior of the arterial wall by considering the composition and function of the tissue. [ABSTRACT FROM AUTHOR]

Since crystal structure dictates the resultant physical properties of materials, titled physical features of the P21 monoclinic SiGe semiconductors, which are still unclear, have been revealed by density functional theory (DFT). The electronic band gap value with 0.49 eV was found to be in the order of previously published cubic and hexagonal closed-packed SiGe semiconductors. Surprisingly, P21 monoclinic SiGe has a room temperature Seebeck coefficient of 1500 μ V/K which is higher than the reported data of both cubic and hexagonal SiGe alloys. Further, the mechanically stable P21 monoclinic phase of the SiGe displays a brittle mechanical character with clear elastic anisotropy has also been deduced. The P21 monoclinic phase of the SiGe can be also considered a good high-dielectric material and beneficial for practical applications of IR or UV goals due to its high refractive index. [ABSTRACT FROM AUTHOR]

Recently, there has been a suggestion that Cu2BaSnS4 could be a promising candidate for a photovoltaic absorber with a wide band gap. The study primarily examined the structural, along with the mechanical and thermodynamic characteristics of Cu2BaSnS4. In addition, a study was performed to examine the presentation and representation of three-dimensional (3D) characteristics related to linear compressibility, shear modulus, and Young's modulus. The investigation into thermodynamic characteristics was calculated and analyzed. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) has sparked intense interest in computational material predictions, especially in electronic band structure, optical dielectric functions, elastic moduli, and phonon calculations using non-local hybrid functionals. Using the first-principle-based calculations, a wide direct Γ-Γ bandgap Eg of 2.68 eV has been reported. Our partial density of states (PDOS) data also demonstrate that the substance exhibits metallic properties, based on the nonzero density of states at Fermi-level EF. Still, what is more, our computational data show the orbital hybridization between Ge 4s2 and S 3p4 electron states on the valence level, and a strong repulsive force occurs on both Ge and S p electron orbitals. The optical absorption coefficient calculated can reach up to 3 × 105 cm−1, indicating good material absorption. Our elastic information provided predicts substance ductility and ionic-covalency of the group IV-VI material. We have also added Vickers hardness and machinability index to our publication, for the sake of completeness. Finally, the slight system instability and weak coupling of the GeS2 material have been observed, according to our phonon dispersion and density of phonon states plot. [ABSTRACT FROM AUTHOR]

For the first time, density functional theory (DFT) calculations have been employed for the measurement of the structural, mechanical, optical, and electrical properties of a bismuth-layered structure ferroelectrics (BLSFs) family member possessing an orthorhombic structure with Cmc21 space group. Based on the exchange–correlation approximation, our calculations show that Pb2Bi4Ti5O18 possesses an indirect band gap, while the materials X2Bi4Ti5O18 (X = Ba, Ca, and Sr) demonstrate direct band gap, where the estimated density functional fundamental band gap values lie between 1.84 to 2.33 eV, which are ideal for photovoltaic applications. The optical performance of these materials has been investigated by tuning the band gaps. The materials demonstrated outstanding optical characteristics, such as high absorption coefficients and low reflection. They exhibited impressive absorption coefficient (α = 105 cm−1) throughout a broad energy range, especially in the visible spectrum (105 cm−1 region). The findings show that the compounds demonstrate lower reflectivity in the visible and UV regions, making them suitable for single-junction photovoltaic cells and optoelectronic applications. The Voigt–Reuss–Hill averaging technique has been employed to derive elastic parameters like bulk modulus (B), Young's modulus, shear modulus (G), the Pugh ratio (B/G) and the Frantesvich ratio (G/B) at 0.1 GPa. The mechanical stability of the compounds was analyzed using the Born stability criteria. Pugh's ratio and Frantesvich's ratio show that all the compounds are ductile, making them ideal for flexible optical applications. [ABSTRACT FROM AUTHOR]

Highlights In order to predict the mechanical behavior of particle reinforced polymer composites, it is crucial to study changes in polymer phase distribution upon interaction with the load in the undeformed state. In this work, HDPE composites reinforced with pyrolytic carbon black (rCBNF) particles, including some rCB modified by mild air oxidation (rCBF), which enabled the aggregation of residual chemisorbed rubber at the surface, examined in a previous work. The development of lamellar morphology induces conformational behaviors resulting from interactions fillers/polymer chains. These interactions cannot be determined by DSC alone but involve short‐range FTIR and Raman and long‐range XRD models. The Raman crystalline content of HDPE was significantly reduced by the presence rCBFs and N330, which varied with lamellar morphology. This process involves the displacement of crystalline lamellae into sublayers by nucleation and crystal growth, resulting in the release of linker molecules, limiting entanglement and improving the elastic properties of the amorphous phase. A significant amount of amorphous phase was produced with N330 and oxidized rCBFs, in which the carbon surface was free of residual rubber. Mechanical tensile tests showed an improvement in the elastic modulus of composites containing these fillers. N330 and oxidized rCBFs have surface free of the residual rubber contained in rCBNF. Significant reduction in the Raman crystallinity of HDPE with rCBF and N330. Reduction varies with lamellar size through nucleation and crystal growth. Strong release of the tie molecule improves the elastic modulus of HDPE/rCBF. Improved mechanical tensile properties of HDPE/rCBF and HDPE/N330. [ABSTRACT FROM AUTHOR]

This work utilizes density functional theory (DFT) to analyze the structural, thermodynamic, mechanical, electro-optic, and electron transport characteristics of Rb2CuAsX6 (X = F, Cl, Br) perovskites. The impact of occupancy of different halide ions at the X-site on the thermodynamic, mechanical, optical, and thermoelectric response of studied compounds has also been evaluated. The investigation of the elastic parameters and formation energy has confirmed that the examined perovskites are cubic in structure, stable, and ductile. The thermodynamic characteristics that rely on temperature are estimated using the quasi-harmonic Debye approach. The thermal features such as entropy, heat capacity, and Debye temperature are calculated and analyzed to assess the stability at elevated temperatures and the suitability of compounds for industrial applications. The band structure computations identified Rb2CuAsF6, Rb2CuAsCl6, and Rb2CuAsBr6 are p-type semiconductors with indirect band gaps of 1.25, 1.10, and 0.83 eV, respectively, which decreases while substituting F with Cl and Br. The optical characteristics such as strong optical absorption (> 105 cm−1) and minimal dispersion in the visible and ultraviolet spectrum highlight their suitability for solar energy conversion and optoelectronics. Additionally, thermoelectric characteristics have been determined, showing a higher thermoelectric figure of merit (ZT) value of 0.80, 0.79, and 0.78, respectively, at room temperature. Our research anticipates these perovskite combinations exhibit superior photoelectric and thermoelectric efficiency, rendering them potential prospects for advanced photovoltaic and thermoelectric devices. [ABSTRACT FROM AUTHOR]

The article deals with the problem of a dynamic model of the truck crane considering the elasticity of the rope and the ground. The dynamic model of a truck crane in the vertical plane has been established. When considering the oscillation of a truck crane, it is a dynamic system with a large number of degrees of freedom. This model will allow us to evaluate the dynamic response of the machine, analyze the vibration of the heavy object being lifted and lowered, and subsequently study stability and control problems. In this paper, the dynamic models of the cranes in the working plane have been established, built by Lagrange's multiplier Equations, which are systems of differential-algebraic Equations with the generalized coordinates of the machine's motions and the elastic coordinates. The Lagrange Equation provides a simple method for solving dynamic problems. The advantage of this Equation is that the form and number of Equations do not depend on the number of objects in the investigated system, nor do they depend on the way the objects move. The number of Lagrange Equations depends only on the number of degrees of freedom of the system. [ABSTRACT FROM AUTHOR]

Researchers seek to measure the extent to which faculty increased their student-centered practices in response to COVID-19 by analyzing course syllabi across three semesters. Faculty were randomly selected from two campuses of a STEM-focused institution (n = 110), each of whom had taught the same course during Fall 2019, Fall 2020, and Fall 2022. Scorers used an abbreviated version of the Student-Centered Syllabus Rubric (Palmer et al., 2014) to identify shifts in student-centeredness over time. Results revealed that 85% of measured syllabi changed over time, with over one-third of measured syllabi reverting to pre-pandemic status. The researchers discuss their methods, results, limitations, and future research opportunities. [ABSTRACT FROM AUTHOR]

Mechanochromic materials provide optical changes in response to mechanical stress and are of interest in a wide range of potential applications such as strain sensing, structural health monitoring, and encryption. Advanced manufacturing such as 3D printing enables the fabrication of complex patterns and geometries. In this work, classes of stretchable mechanochromic materials that provide visual color changes when tension is applied, namely, dyes, polymer dispersed liquid crystals, liquid crystal elastomers, cellulose nanocrystals, photonic nanostructures, hydrogels, and hybrid systems (combinations of other classes) are reviewed. For each class, synthesis and processing, as well as the mechanism of color change are discussed. To enable materials selection across the classes, the mechanochromic sensitivity of the different classes of materials are compared. Photonic systems demonstrate high mechanochromic sensitivity (Δnm/% strain), large dynamic color range, and rapid reversibility. Further, the mechanochromic behavior can be predicted using a simple mechanical model. Photonic systems with a wide range of mechanical properties (elastic modulus) have been achieved. The addition of dyes to photonic systems has broadened the dynamic range, i.e., the strain over which there is an optical change. For applications in which irreversible color change is desired, dye-based systems or liquid crystal elastomer systems can be formulated. While many promising applications have been demonstrated, manufacturing uniform color on a large scale remains a challenge. Standardized characterization methods are needed to translate materials to practical applications. The sustainability of mechanochromic materials is also an important consideration. [ABSTRACT FROM AUTHOR]

Herein, the structural, mechanical, optoelectronic, and transport properties of double perovskites A2ScCuCl6 (A = K, Rb, and Cs) have been determined through simulations using density functional theory. The stability of K2ScCuCl6, Rb2ScCuCl6, and Cs2ScCuCl6 compounds is supported by the optimization of structural configuration and estimation of negative formation energy. The mechanical parameters are computed to quantify mechanical strength, stability, and anisotropy. The compounds that were investigated exhibit semiconductor properties, with an indirect bandgap of 1.55, 1.43, and 1.30 eV using TB-mBJ potential, respectively. The density of states also reveals the band gap and semiconductor properties of the materials. The optical characteristics of the materials have been analyzed in terms of the dielectric function, absorption, reflectance, and optical loss. The projected low excitons binding energy, high absorbance in visible and ultraviolet regions, minimal reflectivity, and energy loss suggest that these materials are highly recommended for utilization in solar energy technology. We examined the transport characteristics that vary with temperature. The combination of high electrical conductivity, moderate thermal conductivity, and higher ZT values of 0.81, 0.86, and 0.77 makes them promising candidates for thermoelectric applications. This analysis ensures that these materials can be utilized in energy conversion applications. [ABSTRACT FROM AUTHOR]

Toll roads are one of the infrastructure development targets in Indonesia to speed up traffic and vehicle travel times. This paper analyzes the flexible pavement structure of the Yogyakarta-Bawen Toll Road. It predicts damage and residual values using elastic and viscoelastic approaches based on MDPJ Bina Marga 2017 using the KENPAVE Program. The recommended design alternative is pavement with a layer of AC-WC 40 mm, AC-BC 60 mm, Base AC 180 mm, and LPA 300 mm. This alternative is predicted to be able to serve load repetitions in the elastic approach of 432,857,828 ESAL until fatigue cracking occurs, 215,176,089 ESAL until rutting occurs, and 136,575,580 ESAL until permanent deformation occurs. Analysis using the viscoelastic approach can provide load repetitions of 153,304,378 ESAL until fatigue cracking occurs, 47,014,109 ESAL until rutting occurs, and 71,859,938 ESAL until permanent deformation occurs. Based on the elastic approach, the pavement's service life is 33 years, with initial damage in the form of permanent deformation. In comparison, the viscoelastic approach has a service life of 22.7 years, with initial damage in the form of rutting.

Considering the anisotropy of the earth media is helpful in reducing the depth error between seismic and drilling and providing reliable imaging data for seismic interpretation and inversion. Transversely isotropic media with a vertical axis of symmetry are the most common type of anisotropic media and have been under constant study. The separation of the P‐ and S‐wavefields, which affects the accuracy of elastic wave imaging and the inversion in transversely isotropic media with a vertical axis of symmetry, is a hot research topic. Among the commonly used wavefield decoupling methods, the S‐wave is typically obtained by subtracting the P‐wave from the total wavefield. However, this kind of wavefield decoupling method often leads to severe P‐wave crosstalk in the separated S‐wavefield; thus, it needs further development. In this paper, the principle that the divergence of the S‐wave is zero is employed to solve the unresolved S‐wave elastic parameters of the S‐wave stiffness matrix by utilizing the modified zero‐order pseudo‐Helmholtz decomposition operator. The obtained S‐wave elastic parameters are employed to construct the qS‐wave stress and facilitate the derivation of the relationship between the qS‐wave particle velocity and the qS‐wave stress. Furthermore, a qS‐wave decoupling first‐order velocity–stress equation, which matches the qP‐wave decoupling first‐order velocity–stress equation, is derived. By jointly using the decoupling equations of qS‐ and qP‐wave, the separation of the P‐ and S‐wavefields in transversely isotropic media with a vertical axis of symmetry is realized. The efficiency of the proposed method is demonstrated via numerical tests conducted to assess the wavefield separation. Moreover, a complex model is employed to perform elastic reverse‐time migration, resulting in the acquisition of accurate imaging results for PP, PS, SP, and SS waves, without the presence of significant artefacts. The correctness of the qS‐wave decoupling equation in transversely isotropic media with a vertical axis of symmetry is confirmed by the comparative tests using decoupling methods in isotropic media. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculations were executed for the titled features of hitherto unreported Rb2XS3 (X = Si, Ge, Sn) chalcogen compounds. All compounds were found to be in semiconducting character where they demonstrate high-k dielectric properties, high optical conductivity, high refractivity and reasonable absorbance. In addition, obtained phonon dispersion curves of all compounds with positive phonon frequencies stipulate the dynamical stability. Also, computed elastic stiffness constants prove mechanical stability and bilateral agreement between Pugh ratio analyses with Poisson ratio results confirms the ductile mechanical feature of all addressed compounds. Overall, with satisfactory optical, elastic and mechanical aspects, Rb2XS3 (X = Si, Ge, Sn) chalcogenides can be promising materials for recent optoelectronics and microelectronics with diverse applications. [ABSTRACT FROM AUTHOR]

The anti/de-icing methods are mainly divided into two types: active method and passive method. The passive method generally adopts three ideas: reducing water contact, inhibiting water icing and reducing ice adhesion. Silica aerogels, which have adjustable surface wettability, thermal conductivity and porosity, would be designed to satisfy the requirement for passive anti/de-icing methods. In this work, the organic–inorganic hybrid aerogels based on organosilicon were facilely prepared in a sol–gel procedure, which showed hydrophobic and elastic properties. It could be seen that the thermal insulation effect originating from aerogel-like porous network endowed the efficient anti-icing property. Moreover, the lowest ice adhesion strengths of the above silica aerogels and the related oil-based lubricant-filled aerogels were 7.1kPa and 5kPa, respectively, which belonged to the icephobic surface. Besides, the ice adhesion strength only increased to 15.6kPa after 30 icing–deicing cycles, showing that hydrophobic and elastic silica aerogels had efficient deicing durability. [ABSTRACT FROM AUTHOR]

In this paper, we will investigate the structural, electronic, mechanical, magnetic and optical properties of Heusler Mn2NiAl (MNA) compound using the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA) of the full potential linearized augmented plane-wave method for exchange and use correlations, modified Becke–Johnson and GGA+U Hubbard parameter. The calculated band structure (BS) and density of states (DOS) of MNA showed a metallic (GGA), nearly half-metallic (mBJ) and half metallic (GGA+U) behavior. Moreover, the magnetic computed magnetic moments by GGA+U are higher compared to GGA and mBJ results. Bulk modulus, shear modulus, Voigt and Reuss polycrystalline elastic modulus, Debye temperature, sound velocities, the melting temperatures, B / G ratio, Young's modulus and Poisson's ratio were obtained. The elastic anisotropy of MNA alloy was analyzed using 2D and 3D figures of directional dependence of Poisson's ratio, shear modulus, linear compressibility and Young's modulus. Studies have shown that the Heusler material MNA has magnetic and anisotropic properties and is mechanically stable. [ABSTRACT FROM AUTHOR]

Nowadays, the most successful applications of full‐waveform inversion (FWI) involve marine seismic data under acoustic approximations. Elastic FWI of land seismic data is still challenging in theory and practice. Here, we propose a full dispersion spectrum inversion method and apply it to seismic data acquired in West Antarctica. Inspired by the conventional surface wave dispersion curve inversion method, we propose to invert the surface wave dispersion spectrum instead of the complicated waveforms. We compare the frequency‐velocity, frequency‐slowness, and frequency‐wavenumber spectra in terms of their ability to resolve dispersion modes and the feasibility of their adjoint updates and conclude that the frequency‐slowness spectrum is the best for our inversion objectives. We test four objective functions, subtraction, zero‐lag crosscorrelation, optimal transport, and the local‐crosscorrelation to quantify the spectrum mismatch and provide the corresponding adjoint source. We then theoretically analyze the convexity of the proposed objective functions and examine their convergence behavior using numerical examples. We also compare the proposed method with the classic FWI method and the traditional surface wave dispersion curve inversion method and discuss the strengths and weaknesses of each method. This technique is employed to evaluate the shallow velocity structures beneath a seismic array stationed in West Antarctica. Our proposed inversion scheme is also useful for more general applications such as imaging the shallow subsurface of the critical zones, like geothermal reservoirs, and CO2 storage sites. Plain Language Summary: Seismic full‐waveform inversion (FWI) is a cutting‐edge inversion method used for uncovering the Earth's subsurface structure. With the growing interest in clean energy and CO2 sequestration, exploring the subsurface in land is becoming crucial. However, there are only a few success stories of seismic FWI applied to land data mainly because of the complexity of the near‐surface and the increased nonlinearity of the problem. Here, we propose a full dispersion spectrum inversion method that seeks optimal velocity models in the subsurface by matching the seismic dispersion spectra. Dispersion spectra are the skeleton of seismic surface waves, which are simpler to quantify yet retain the key dispersion information of surface waves. It is generally easier for humans, as well as algorithms, to match simplified representations of the observed and simulated data, such as the dispersion spectrum, instead of the seismic waveforms themselves. The proposed method expands conventional 1D dispersion curve inversion to multiple dimensions and is accomplished under the framework of FWI. The proposed inversion method applies to seismic imaging applications in exploration and global seismology. Key Points: We propose a full dispersion spectrum inversion method for imaging the near‐surface and apply it to seismic array data collected in West AntarcticaThe surface wave frequency‐slowness spectrum is preferred over the frequency‐velocity and the frequency‐wavenumber spectra to measure the misfit in the proposed inversionThe optimal transport objective function is immune to cycle skipping but has a lower model resolution [ABSTRACT FROM AUTHOR]

Imaging of the first metres of the subsurface with seismic methods constitutes a key challenge for several applications. In this context, the analysis of Rayleigh waves can reveal information about the S-wave velocity structure in the first metres of the subsurface. The waves recorded can be inverted using several techniques, of which the most widely used is the multichannel analysis of surface waves, where dispersion curves are picked on the velocity-frequency spectrum. A full-waveform inversion of surface waves has been implemented, offering the possibility to exploit the complete information content of the recorded seismograms. This method has only recently been tested with elastic approximation on synthetic data, as the application in near-surface scenarios is very challenging due to the high nonlinearity of the problem and the considerable computational costs. This paper presents a gradient-based Markov chain Monte Carlo elastic full-waveform inversion method, where posterior sampling is accelerated by compressing data and model spaces through the discrete cosine transform and, also, by defining a proposal that is a local, Gaussian approximation of the target posterior probability density. The applicability of the approach is demonstrated by performing two synthetic inversion tests on two different near-surface models: a two-layered model with lateral velocity variations, and a four-layered model with velocity inversions. [ABSTRACT FROM AUTHOR]

In this work, the WIEN2k computer code was used to investigate the structural, elastic, electronic, magnetic, optical, thermoelectric, and dynamic properties of the CoCrTe half-Heusler (HH) compound. The Full-Potential Linearized Augmented Plane Wave method and Density Functional Theory were both used in this work. To further understand the electronic band gap, we used the modified Becke Johnson exchange–correlation functional method. We investigated the CoCrTe HH compound's electronic characteristics using density of states plots and band structure plots. By calculating magnetic moments and observing the behavior of spin-polarized electronic states, we also investigated the magnetic properties. Additionally, the CoCrTe HH compound's elastic properties were identified. These characteristics, including stiffness, resilience, and overall stability, offer crucial information about how the material reacts to mechanical deformation. Properties studied emphasized that the compound is metallic, and it appears as a good thermoelectric material. Finally, the compound's dynamic properties show that it is dynamically stable as well as mechanically. [ABSTRACT FROM AUTHOR]

It remains challenging for elastic full waveform inversion (EFWI) to characterize the elastic properties of a target reservoir deep beneath complex overburden media. This can be attributed to two factors. (1) The complex wavefield distortions arising from the overburden obscure the target reflection properties, resulting in a target zone with limited energy illumination. (2) High-resolution EFWI for the whole inversion domain is computationally expensive. To overcome these challenges, instead of directly inverting for the subsurface model using surface seismic data, we develop a target-oriented elastic waveform inversion scheme. We first retrieve the elastic reflection response to the target zone of interest by projecting seismic data from the surface to the datum level. Then, we can apply high-resolution EFWI on the target zone by using the retrieved elastic reflection data. To better handle the complex overburden, which may include anisotropy and salt bodies, we make full use of the prior estimate of the overburden in the redatuming process to obtain a reliable reflection response to the target zone. In the numerical examples, we use the SEG Advanced Modeling (SEAM) model with an anisotropic overburden and a salt body model to demonstrate the feasibility and effectiveness of the proposed method and analyze the influence of anisotropy and high-contrast salt in the overburden on the redatuming and inversion results, respectively. [ABSTRACT FROM AUTHOR]

This research employs the FP-LAPW approach within density functional theory to investigate the structural, optical, electronic, and elastic features of GaXCl3 (X = Be, Ca) chloroperovskites. The computational analysis, incorporating Birch Murnaghan curve optimization for structural stability and IRelast for elastic constants, affirms the anisotropic, ductile, and mechanically stable nature of both GaBeCl3 and GaCaCl3. Electronic characteristics are examined using the Tb-mBJ potential, revealing GaBeCl3 as semiconducting with a 3.03 eV direct band gap (M-Γ) and GaCaCl3 as insulating with a 4.90 eV direct band gap (X–X). Total and partial densities of states (TDOS and PDOS) provide insights into the contributions of elemental states to the band structure. Optical features explored up to 13 eV emphasize significant peaks in the spectra based on observed electronic structures. These findings contribute to a more thorough comprehension of the physical characteristics of chloroperovskites based on Gallium, paving the way for their utilization in optoelectronic devices and as insulating materials. [ABSTRACT FROM AUTHOR]

Background: Many variables affect the pressure caused by splinting or casting. The purpose of this study was to compare pressure underlying a splint wrapped with either an elastic bandage or a bias cut stockinette. Methods: Thirty-two plaster volar resting splints were applied to a simulated extremity with a saline bag secured to it. A pressure transducer was connected to the saline bag to monitor changes in pressure once splints were applied, and 15 mL increments of saline were added to the bag to simulate swelling. Each dressing type was tested with normal application and tight application. Results: Normal application splints wrapped with either bias cut stockinette or an elastic bandage demonstrated similar initial splint pressures (P =.81). With simulated swelling, splints wrapped with bias cut stockinette demonstrated a 15 mmHg (95% confidence interval [CI], 1.5-28.5) higher average pressure than those wrapped with an elastic bandage (P =.035). Tight application splints with an elastic bandage wrap demonstrated a 46 mmHg (95% CI, 16-77) higher initial splint pressure than those wrapped with bias cut stockinette (P =.009). Conclusions: Splints wrapped using either an elastic bandage or bias cut stockinette appear to have a similar safety profile, although in cases of excessive swelling, an elastic bandage may provide additional compliance. Tight splint application appears to be more hazardous with the use of an elastic bandage compared with a bias cut stockinette. Further study of the use of elastic bandages and bias cut stockinettes in the clinical setting may be warranted. [ABSTRACT FROM AUTHOR]

Five glass samples with the following chemical formation: 21.5 SiO2-58.5B2O3-(20-x) ZnO- xLa2O3, where x = 0–10 mol% were fabricated utilizing melt quenching. With an increase in La2O3, the glasses' density increased from 3.174 to 4.754 g/cm3. Experimental data were used to evaluate the mechanical characteristics, and the Makishima and Mackenzie model's semi-empirical methods were used to analyze the elastic properties. As the amount of La2O3 increases, there's a noticeable rise in the velocity of ultrasonic waves. This heightened velocity is likely linked to the strengthening or increased rigidity of the glass network. Elastic moduli values of the glasses under investigation increase with an increase La2O3 content. Employing Phy-X/PSD code, the radiation attenuation behaviour of zinc borosilicate glasses with varying La2O3 concentrations were examined. With increased energy, the enhancement LAC decreases from 2.576 to 0.0375. The ZBSL10 glasses demonstrated strong mechanical and physical characteristics as well as radiation shielding capabilities. The features of the ZBSL glasses are particularly attractive for a variety of mechanical and shielding applications. [ABSTRACT FROM AUTHOR]

We investigate the pressure effect on Li4OX2 (X = Cl, Br, and I) for the first time using DFT simulation. Li4OCl2 shows mechanical stability up to 8 GPa, whereas Li4OBr2 has stability up to 30 GPa pressure according to the Born stability criteria. In contrast, Li4Ol2 becomes unstable above 3.0 GPa pressure. Hence, anomalies were observed for Li4OX2 (X = Cl, Br, and I) solid electrolyte for elastic parameters, Cij under pressure study. The elastic moduli are isotropic in the xy plane, conversely, along the xz and yz plane anisotropic behavior is observed. There is a band gap that exists at zero temperature and pressure. The contribution at the fermi level mainly comes from the O 2p states. The highest reflectivity (∼98 %) was observed for Li4OCl2 at ∼ 17 eV in the IR-visible-UV region showing that this material under study may be considered as a potential coating material to avoid solar heating. The smaller value of the volume thermal expansion coefficient for Li4OCl2 indicates stronger atomic bonding exists, which was also observed from the elastic parameter analysis.

This work examined the SiO2–Pb3O4–ZnO–Y2O3 glasses mechanical, structural, and radiation shielding features. X-ray diffraction is a powerful technique for investigating the structural properties of these glasses. Experimental results were used to evaluate the mechanical characteristics, and the Makishima and Mackenzie model's semi-empirical approaches were used to investigate the elastic properties. Longitudinal velocity VL increase from 4935 m/s to 5325 m/s, while transverse velocity VT increase from 2520 m/s to 2905 m/s. Hardness improved from 4.41 to 8.31 GPa. The behaviour of the elastic moduli at both theoretical and experimental levels is the same. The mass attenuation coefficients (MAC), mean free paths (MFP), tenth & half-value layers (TVL), (HVL), and energy building factors (EBF) were estimated. Overall, higher MAC values were produced by a decrease in ZnO concentration and an increase in Y2O3 content. As the concentration of Y2O3 increases, the MFP, TVL, and HVL values decrease. Better radiation shielding is provided by lower MFP, TVL, and HVL values. The MFP, TVL, and HVL values are lower in the G 5 sample with the Y2O3 contribution (5%, mole). Higher concentrations of Y2O3 in glasses with a SiO2-Pb3O4-ZnO-composition were shown to have improved radiation shielding properties. [ABSTRACT FROM AUTHOR]

Double perovskites have harvested considerable attention in the realm of solar cells and renewable energy applications. Therefore, in this current study, we explored the structural, electronic, and optical properties of Rb2InGaCl6 and Rb2InGaF6 using DFT-based simulations with WIEN2K codes. It is unequivocally established that both compounds demonstrate structural and mechanical stability. Structural stability is further evaluated using Goldsmith's tolerance factor (τG). The τG values of 4.29 and 3.77 are considered acceptable for ensuring the stability of cubic structures for Rb2InGaCl6 and Rb2InGaF6 respectively. It is determined that both compounds are stable elastically and possess ductile characteristics, allowing them to undergo plastic deformation without fracturing. Our investigation reveals indirect band gaps of 1.7 eV (semiconductor) for Rb2InGaCl6 and 4.8 eV (insulator) for Rb2InGaF6. These diverse band structures open up exciting possibilities for optoelectronic applications. Regarding optical properties, the spectral curves of various parameters are examined in the range of 0 eV to 15 eV incident photon energy. The findings reveal the exceptional optical performance of Rb2InGaCl6 and Rb2InGaF6, particularly by their notably high absorption coefficients α(ω). Specifically, Rb2InGaCl6 demonstrates a remarkable absorption of 6.635 at 2.05 eV, while Rb2InGaF6 exhibits a significant absorption of 3.91 at 4.78 eV. The optical conductivity σ(ω) attains peak values, reaching 4.60 for Rb2InGaCl6 and 2.85 for Rb2InGaF6. Furthermore, the optical reflectivity R(ω) peaks at 13.60 eV for Rb2InGaCl6 and 6.30 eV for Rb2InGaF6. Lastly, the energy loss functions L(ω) attain their highest values of 0.57 and 7.58 for Rb2InGaCl6 and Rb2InGaF6, respectively. These results collectively emphasize the impressive optical characteristics of these compounds across a range of energy levels. These findings suggest promising potential energy applications for these materials, particularly in influencing electromagnetic radiation within the ultraviolet (UV) spectrum ranges. [ABSTRACT FROM AUTHOR]

A unique three-dimensional model of generalized thermoelasticity, incorporating a single relaxation time and relying on stress gradient nonlocal elasticity, is presented in this study. The fundamental coupled equations governing the model are applied to a semi-infinite spatial medium with a rigidly fixed bounding surface, which is exposed to a time-dependent thermal shock. The general solution for the field variables is obtained in a closed form through the utilization of normal mode analysis and the eigenvalue approach technique. Numerical results, specific to a substance resembling copper, are provided for the field variables. Parametric studies are conducted to assess the impact of elastic nonlocality on various physical quantities. The graphical representation reveals a noteworthy influence of the nonlocal parameter on the field variables. The study further discusses and compares predictions from the new model with the Lord and Shulman theory of generalized thermoelasticity. Ultimately, the article concludes with a summary of key remarks. [ABSTRACT FROM AUTHOR]

In order to achieve diversification of material functions, extend the service life of materials, and develop the excellent properties of materials themselves, this paper takes elastic polyurethane (EPU) as the matrix and thermoplastic polyurethane (TPU) as the transition phase, a series of shape memory EPU-TPU composites with self-healing function were prepared based on the different proportions of EPU and TPU. The structure, thermal properties, mechanical properties, and shape memory properties of the raw materials and composites were tested and characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and a universal testing machine. The self-healing performance and self-healing mechanism of composites were analyzed. The results show that the shape memory effect of EPU-TPU (3:7) is the best, with a fixed rate of 100% and a recovery rate of 98.9%. It takes more than 258 s to recover from the temporary curled shape to the initial strip shape, with fast thermal response. In addition, EPU-TPU (3:7) and EPU-TPU (2:8) also show good self-healing ability, with the strain after healing reaching about 600%. [ABSTRACT FROM AUTHOR]

Deep neural network (DNN) has achieved great success in various fields. Due to its high computing and storage costs, it is difficult to directly deploy them to resource constrained mobile devices. To solve this problem, the importance evaluation of the global filter in the network is studied, and a channel pruning compression method with filter elasticity is proposed to reduce the size of the neural network. Firstly, the method sets the local dynamic threshold between layers to improve the shortage of over pruning in L1 regularization (L1 lasso) sparse training. Then, its output is multiplied by the channel scaling factor to replace the ordinary convolution layer module. The importance of the global filter is defined by the elastic size of the filter. Its values are estimated and ranked by Taylor formula. At the same time, a new iterative pruning framework of the filter is designed to balance the contradiction between the pruning performance and the pruning speed. Finally, the improved L1 regularization training and the importance of the global filter are used to prune the composite channels. VGG-16 is tested on CIFAR-10 using the proposed method, which reduces 80.2% of floating-point operations (FLOPs) and 97.0% of parameter quantities, without significant loss of accuracy, indicating the effectiveness of the method, which can compress neural networks in a large scale, and can be deployed to resource constrained terminal devices. [ABSTRACT FROM AUTHOR]

Copyright of Wool Textile Journal is the property of National Wool Textile Science & Technology Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon reservoirs. Seismic migration aims at obtaining structural images of subsurface geologic discontinuities. More specifically, seismic migration estimates the reflectivity function (stacked average reflectivity or pre-stack angle-dependent reflectivity) from seismic reflection data. On the other hand, seismic inversion quantitatively estimates the intrinsic rock properties of subsurface formulations. Such seismic inversion methods are applicable to detect hydrocarbon reservoirs that may exhibit lateral variations in the inverted parameters. Although there exist many differences, pre-stack seismic migration is similar with the first iteration of the general linearized seismic inversion. Usually, seismic migration and inversion techniques assume an acoustic or isotropic elastic medium. Unconventional reservoirs such as shale and tight sand formation have notable anisotropic property. We present a linearized waveform inversion (LWI) scheme for weakly anisotropic elastic media with vertical transversely isotropic (VTI) symmetry. It is based on two-way anisotropic elastic wave equation and simultaneously inverts for the localized perturbations (ΔVp0 =Vp0;ΔVs0 =Vs0;Δe;Δδ) from the longwavelength reference model. Our proposed VTI-elastic LWI is an iterative method that requires a forward and an adjoint operator acting on vectors in each iteration. We derive the forward Born approximation operator by perturbation theory and adjoint operator via adjoint-state method. The inversion has improved the quality of the images and reduces the multi-parameter crosstalk comparing with the adjoint-based images. We have observed that the multi-parameter crosstalk problem is more prominent in the inversion images for Thomsen anisotropy parameters. Especially, the Thomsen parameter d is the most difficult to resolve. We also analyze the multi-parameter crosstalk using scattering radiation patterns. The linearized waveform inversion for VTI-elastic media presented in this article provides quantitative information of the rock properties that has the potential to help identify hydrocarbon reservoirs. [ABSTRACT FROM AUTHOR]

In this study, we propose a frequency‐domain autocorrelation as an imaging condition for time‐reversal imaging. The previous imaging conditions in time‐reversal imaging require time‐domain calculations such as inverse Fourier transform. The computational burden of these calculations is critical; therefore, time‐reversal imaging is not the proper method for real‐time event localization. We exclude these time‐domain calculations for efficiency. Instead, the maximum amplitude position of the frequency‐domain autocorrelation of the time‐reversal wavefield is determined as a source location. We conducted numerical tests to validate our imaging condition. The synthetic data test shows that our proposed algorithm provides a more credible source localization result than the conventional grid‐search method does in a noisy environment even using only one frequency component with many receivers. We also applied our algorithm to two real datasets acquired from the small monitoring network in Pohang. The real‐data test shows a comparable result with the result of the grid‐search method. [ABSTRACT FROM AUTHOR]

Unconsolidated sandstones are attractive targets for underground storage of carbon due to their high porosity and permeability. Monitoring of injection and movement of CO2 in such formations using elastic waves requires an understanding of the acoustic properties of the sandstone. Current approaches often use the so‐called soft‐sand model in which a Hertz–Mindlin model of the acoustic properties at high porosity is mixed with the acoustic properties of the mineral phase to predict the acoustic properties over the entire porosity range. Using well‐log data from two unconsolidated sand formations of interest for CO2 storage, we discuss the limitations of this model and provide an alternative approach in which the mechanical properties of grain contacts are obtained by inversion, and the properties of infill material lying within the pore space are estimated. The formations considered are the Paluxy Formation in Kemper County, Mississippi, and the Frio Formation near Houston, Texas. The ratio of the normal to shear compliance of the grain contacts is found to be significantly less than unity for both formations. This implies that the grain contacts are more compliant in shear than in compression. However, the grain contact compliance is higher and the ratio of the normal to shear compliance is lower for the Frio example than for the Paluxy case, and this may lead to sliding at grain contacts with low shear compliance and transport of grains during fluid flow, particularly if CO2 acts to weaken any cement that may be present at the grain contacts. Such transport was suggested by Al Hosni et al. in explaining why the magnitude of the time‐lapse effect due to the injection of CO2 at the Frio CO2 injection site is greater than predicted using conventional rock physics models. A simple model of the mechanical properties of infill material lying within the pore space suggests that the bulk and shear moduli of infill material in the Paluxy case are significantly higher than the Frio case, consistent with the lower grain contact compliance in the Paluxy case. [ABSTRACT FROM AUTHOR]