Elastic Properties Research Articles

Investigation of optoelectronic, mechanical and thermodynamic properties of cubic perovskite FrBCl3 (B = Zn, Cd) in approach of density functional theory

Lead-free cubic metallic halide perovskite (MHP) compounds, FrBCl3 (where B = Zn, Cd), have been evaluated using first-principles density-functional theory (DFT). Both FrZnCl3 and FrCdCl3 satisfy the stability conditions determined by their tolerance and octahedral factors. These materials demonstrate the characteristics of indirect band gap semiconductors, and their high optical absorption coefficients create promising opportunities for the advancement of optoelectronic devices. The elastic properties of both perovskites indicate robust mechanical stability, while their ductility, flexibility, and stiffness suggest potential for thin film fabrication. Furthermore, the Debye temperature profile underscores the thermal stability of these compounds. This computational study reveals coherent relationships among their structural, electronic, optical, mechanical, and thermodynamic properties. Consequently, these materials may offer exciting applications in nuclear medicine, X-ray imaging, and a variety of optoelectronic devices.

Adhesive paperboard connections in architectural applications: modelling, characterization, and performance assessment

ABSTRACT Paper-based elements have been researched as cheap and pro-ecological building materials for several decades and bonding is the most widely used method of joining them. However, adhesives may increase the cost, weight, and environmental impact of the component. The suitability of different adhesive types for paper-based building component bonding has not yet been researched. This work evaluates the properties of six types of commercially available adhesives – polyvinyl acetate, dextrin, and synthetic rubber. The results of single-lap tensile tests served as the input for a Goland–Reissner model of adhesive stresses. The elastic properties of the adhesives were estimated based on tensile test results – Shear modulus ranging from 0.626 to 1.097 MPa and Young’s modulus from 0.703 to 2.940 MPa. The modelled shear strength ranged from 1.1922 to 1.6115 MPa and the peel strength from 0.3265 to 0.5894 MPa. Recommendations for adhesive use in paper-based building elements are formulated. Polyvinyl acetate adhesives may be recommended for general use; however, the use of starch/dextrin adhesives should not be neglected. The presented work successfully demonstrates a methodology to obtain properties of adhesives for the mechanical assessment of the bonds from simple tensile tests of single-lap joints.

Structural, Elastic, Electronic, Dynamic, and Thermal Properties of SrAl2O4 with an Orthorhombic Structure Under Pressure.

Its outstanding mechanical and thermodynamic characteristics make SrAl2O4 a highly desirable ceramic material for high-temperature applications. However, the effects of elevated pressure on the structural and other properties of SrAl2O4 are still poorly understood. This study encompassed structural, elastic, electronic, dynamic, and thermal characteristics. Band structure calculations indicate that the direct band gap of SrAl2O4 is 4.54 eV. In addition, the Cauchy pressures provide evidence of the brittle characteristics of SrAl2O4. The mechanical and dynamic stability of SrAl2O4 is evident from the accurate determination of its elastic constants and phonon dispersion relations. In addition, a comprehensive analysis was conducted of the relationship between specific heat and entropy concerning temperature variations.

Prediction of Thin Shoal Reservoirs Under Reef Controlled by Isochronous Stratigraphic Framework

Despite the great success in the global exploration and development of reef reservoirs, research on bioclastic shoals under reefs is still in its infancy. Bioclastic shoal reservoirs are very thin, with multiple vertical levels and fast lateral changes, which makes accurate prediction of the reservoir’s location much tougher. To further implement the reservoir distribution, under the guidance of sequence stratigraphy, the prediction of thin shoals under the control of an isochronous stratigraphic framework was established. Using the combination of spectrum shaping and F-X domain noise suppression techniques and utilizing the signal-to-noise ratio spectrum set as the reference, logging curve as supervision, and well seismic calibration and isochronal amplitude slicing as quality control, the seismic frequency band was extended, and the seismic data resolution and signal-to-noise ratio were improved. After frequency extension, the global optimal seismic automatic interpretation technique was used to construct an isochronal stratigraphic framework model. Through waveform facies-controlled inversion and waveform facies-controlled simulation techniques, the elastic properties of the shoal reservoir were obtained, from which the planar distribution of the reservoir was accurately predicted. The above methods were applied to the prediction of the bioclastic shoal reservoir in the lower submember of the Changxing formation in the Yuanba gas field (China). The plane distribution of bioclastic shoal in the first and second levels was identified, which provides a guideline for the prediction of thin shoal reservoirs.

Ab initio investigation of structural, elastic, dynamic, and electronic properties of YN binary rare earth nitride in ZB cubic phase

This research employs ab initio calculations, utilizing the FP-LAPW method as implemented in WIEN2k and the PP-PW method in QUANTUM ESPRESSO, within the framework of the GGA-PBE approximation, to investigate the physical properties of the rare earth nitride binary YN. Structural parameters of YN are determined, yielding predictive results consistent with recent calculations. Furthermore, a comprehensive investigation into mechanical behavior and elastic properties confirms the mechanical stability of YN in its cubic ZB structure. An analysis of the anisotropy coefficient reveals its elastic anisotropy. The dynamic stability of YN is investigated through PW-scf calculations using DFPT theory, enabling the calculation of phonon spectra, frequencies, and polarization vectors. These findings affirm the stability of YN material in the B3 structure, which can be experimentally synthesized. Electronic properties are probed, showing semiconductor behavior, utilizing GGA mBJ, and YS PBE0 methods to ascertain band gap values in the B3 structure. This suggests its potential for adoption in optoelectronic and photonic devices.

Comprehensive approach on La1-xPbxMnO3 (0.2 ≤ x ≤ 0.5) perovskites synthesized by solid state reaction technique

We have synthesized Pb concentrated La manganites La1-xPbxMnO3 (0.2 ≤ x ≤ 0.5) using solid state reaction route to investigate several physical properties such as structural, thermal, magnetic, electronic and elastic properties via both the experimental characterizations and the first principles calculations under the framework of density functional theory (DFT). The structures of the studied perovskites are examined by X-ray diffraction (XRD) pattern and also compared with the crystallographic data obtained by computations. The crystallization and formation of the studied phase of manganites are confirmed by analyzing the thermogravimetric (TG) curve. The temperature dependence of magnetization of all the samples exhibits a ferromagnetic metal phase with the Curie temperatures TC ranging from 334 to 338K. Although a metal-semiconductor transition is expected at around TC for the measurement of electrical resistivity with temperature but we observe semiconducting behavior because of the resistivity data started from room temperature. The calculated energy dispersion of all the manganites shows metallic conduction in conformity with the available experimental results. All the studied perovskites under investigation possess mechanical stability, malleability as well as anisotropy. The calculated Debye temperatures of all the Pb-doped La manganites show excellent correspondence with the other thermophysical parameters like melting point, phonon thermal conductivity and hardness as well.

Machine Learning Prediction of Permeability Distribution in the X Field Malay Basin Using Elastic Properties

Machine Learning Prediction of Permeability Distribution in the X Field Malay Basin Using Elastic Properties

Nanostructured silver vanadate gel: Evaluation of physicochemical, mechanical, and antibiofilm properties against a five-species oral model

The aim of this study was to develop a gel with nanostructured silver vanadate decorated with silver nanoparticles (β-AgVO3) and to evaluate its physicochemical, mechanical, and antibiofilm properties against a five-species oral model composed of Candida albicans, Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa. The formulations were prepared with 0 % w/v (G0), 0.02 % w/v (G1), 0.05 % w/v (G2), and 0.12 % w/v (G3) β-AgVO3. The physicochemical properties of pH (n = 5), viscosity (n = 5), spreadability (n = 10) and syringability (n = 10) were evaluated, as well as the mechanical properties of hardness, cohesiveness, compressibility, elasticity, and adhesiveness using the texture profile assay (TPA) (n = 5) and ex vivo mucoadhesion (n = 5). The antibiofilm effect was assessed by counting colony-forming units (CFU/mL) (n = 8), metabolic activity (XTT) (n = 8), and scanning electron microscopy (SEM) (n = 1), using 0.12 % chlorhexidine gel (CG) as a positive control and G0 as a negative control. All groups demonstrated a neutral pH. G2 and G3 exhibited reduced viscosity and syringeability, along with increased spreadability. The incorporation of β-AgVO3 did not impact the gel's elasticity or cohesiveness but led to a decrease in hardness, compressibility, and adhesiveness. Ex vivo mucoadhesion was not altered by the addition of the nanomaterial. G3 showed a higher microbial reduction compared to GC and G0. It was concluded that the formulations with β-AgVO3 showed compatible physicochemical and mechanical properties for application and maintenance in the oral cavity. G3 showed superior antimicrobial effect against all microorganisms compared to GC and G0.

Eco-friendly property modulation of biobased gels of carboxymethyl cellulose-integrated poly(tertiary amine)s for the removal of azo-food dyes

Anionic polysaccharide-based gels enable the design of biobased materials with biochemical properties, non-toxic and natural origin. A new set of cationic gels was prepared from carboxymethylcellulose (CMC)-doped tertiary amino functional cationic monomers 2-(dimethylamino)ethyl methacrylate and N-(3-(dimethylamino)propyl) methacrylamide via the formation of semi-interpenetrated network (semi-IPN) at different polymerization temperatures, Tprep. A detailed understanding of the temperature-dependent synthesis and physicochemical response is required for the design of interpenetrating networks with CMC as an adsorbent that provides effective sources for the removal of azo-food dyes such as tartrazine and carmoisine from aqueous solutions. The variation of elasticity and swelling properties with respect to polymerization temperature was investigated. CMC-integration and polymerization temperature played a decisive role in the compressive elasticity. Incorporation of CMC into copolymer matrix led to a significant increase in elasticity of semi-IPNs, while mechanically weaker gels were obtained with increasing Tprep. Addition of CMC increased the swelling modulus of semi-IPNs formed at −18 °C by 2.6-fold. While the transparency changed depending on Tprep and microstructure, addition of CMC decreased the swelling rate of gels at all polymerization temperatures. The compressive modulus decreased with the swelling process in accordance with the Rubber elasticity theory. Semi-IPN gels showed stable swelling against pH-change in aqueous solutions and exhibited excellent pH-sensitivity significantly in low pH. A 4 to 12 fold decrease in maximum volume was observed by varying the pH between 2.1 and 9.8. The correlation between polymerization temperature and removal of azo-food dyes; tartrazine and carmoisine from contaminated wastewater with CMC-based gels was studied. Dynamic adsorption equilibrium was reached in 30 min, and tartrazine and carmoisine removal performances varied between 92.8 % and 98.4 %. respectively. The adsorption data for azo-dyes were evaluated by Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Redlich-Patterson, Sips, and Tooth isotherm models, but were best described by Langmuir and Redlich-Patterson models as they gave the highest correlation. Pseudo-first order, pseudo-second order, Elovich, Avrami kinetic and intra-particle diffusion models were investigated and dye adsorption was represented by pseudo-second-order model. After the adsorption process, semi-IPNs can easily be regenerated and effectively reused over five cycles. The study provided new insights towards the facile and sustainable synthesis of eco-friendly multifunctional CMC-based gels carrying tertiary amino groups for effective removal of azo-based food colorants.

KH571 construct interfacial molecular bridge in calcium silicate/TMPTA/HDDA scaffolds for improving mechanical properties, biodegradability and photopolymerization

Digital Light Processing (DLP) offers the potential for personalized bone implants. Within this method, the interfacial bonding capacity of inorganic/organic materials and the solid-phase content of the slurry emerge as primary factors influencing scaffolds mechanical properties. In this research, KH571 was applied to establish an interfacial “molecular bridge”, adopting in situ coupling technology to forge stable covalent bonds between calcium silicate (CSi) and KH571. Chemical grafting, surface photografting, and photopolymerization techniques were then utilized to construct a photo-crosslinked network by CSi-KH571-TMPTA/HDDA slurry, thereby transforming the weak physical connections at the interface into strong chemical bonds. Consequently, the curing capacity and mechanical properties of the scaffolds were enhanced. Further control grain size, crystal phase transition, and shrinkage of CSi-KH571 scaffolds, post-treatment sintering processes were employed, resulting in scaffolds with a high content of β-CSi. Moreover, the optimal process parameters were selected concerning grafting rate, chemical composition, microscopic morphology, crystalline transformation, dimensional accuracy, mechanical properties, biodegradability and biocompatibility of CSi-KH571. The elastic modulus and compressive properties of CSi25-55 scaffolds exhibited a notable improvement of 29.71 % and 59.30 %, respectively, compared to CSi-50 scaffolds. By regulating the phase composition of CSi, CSi25-55 scaffolds were designed to possess a controllable degradation. In vitro cell culture experiments validated its excellent biocompatibility and promoted the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs) as well as the deposition of bone matrix. Herein, a novel and sustainable approach has been promoted for enhancing the interfacial bonding capacity of inorganic/organic materials and the solid-phase content of printing slurry, which lays the foundation for the printing of high-resolution degradable bioceramic scaffolds.

DFT-Based Prediction of Promising Structural, Elastic and Thermoelectronic Properties in BaAgX3 (X= I, Br, and Cl) Halide Perovskites.

DFT-Based Prediction of Promising Structural, Elastic and Thermoelectronic Properties in BaAgX3 (X= I, Br, and Cl) Halide Perovskites.

Practical approach for sand-shale mixtures classification based on rocks multi-physical properties

Sandstones are the most common reservoir rocks, providing reservoirs for oil and gas and serving as reservoirs for groundwater. The Gulf of Mexico is known for its sand-shale mixtures and potential for its oil and hydrate gas resources in sandstone units. Understanding these variations is essential for assessing hydrocarbon potential and unconventional prospectivity. In this study, we utilized the Elastic, Electrical, and Radioactive (EER) properties of rocks for lithological categorization of well logging data, leading to the development of a novel rock physics template. The electrical and radioactive properties of the rocks facilitated a broad lithological classification, while their elastic characteristics helped distinguish between porous and low-porosity zones. Electrical and radioactive properties are utilized for well data classification because in sandstone formations, there is a decrease in log gamma and an increase in log resistivity. As a result, these opposing shifts in the two geophysical logs enhance the spread of data points on the lithological resistivity-gamma ray scatter plot, thereby simplifying the process of lithological categorization. Ultimately, the well logging data was sorted into three distinct categories: low shale sands (shale volume < 30 %), sand-shale mixtures (shale volume = 30 to 80 %), and shale-dominated areas. Subsequently, the Thomas Stieber model was employed to identify the types of clay minerals present in both sandstones and sand-shale mixtures. The model's findings revealed that dispersed type clay minerals are predominantly found in sandstones, with laminar and structured types being relatively rare. However, in sand-shale mixtures, both dispersed and laminar clays observed.

Theoretical Investigation of Transition Metal (Cr, Fe)-Doped AlN in a rocksalt structure: A DFT Study on Physical Properties

This study presents first-principles computations to explore the structural, electronic, optical, elastic, vibrational, and thermodynamic properties of Aluminum Nitride (AlN) doped with the transition metals Chromium (Cr) and Iron (Fe) in the rocksalt structure. Using spin-polarized density functional theory (DFT) within the CASTEP code, we applied GGA-PBE, GGA+U, and HSE06 approximations for exchange-correlation functions. Our results reveal that Cr doping transforms AlN into a dilute magnetic semiconductor (DMS), while Fe doping induces a transition to a metallic state. Both Al0.₇₅Cr₀.₂₅N and Al₀.₇₅Fe₀.₂₅N exhibit strong covalent bonding, contributing to enhanced hardness. The substantial increase in static dielectric constant and refractive index suggests strong optical responses. Furthermore, our analysis confirms the mechanical and dynamic stability of these compounds. Al₀.₇₅Cr₀.₂₅N is a promising candidate for electronic and spintronic applications, whereas Al₀.₇₅Fe₀.₂₅N, with its high conductivity, is well-suited for magnetic storage devices and electrical contacts. Our findings for AlN are consistent with prior theoretical and experimental data, while the results for Al₀.₇₅Cr₀.₂₅N and Al₀.₇₅Fe₀.₂₅N offer novel insights for future research.

The Structural, Elastic, and thermodynamic properties of Sr2P7Br Double Zintl salt with heptaphosphanortricyclane configuration

We investigated the effects of externally applied pressure on the Sr2P7Br compound’s properties, specifically its crystalline structure, elasticity, and thermodynamics. This investigation was carried out using the pseudopotential plane wave method within the framework of density functional theory. We used the well-known PBEsol variant of the exchange–correlation general gradient approximation specifically designed for solid-state analysis. This is the first endeavor to investigate the effects of pressure on the Sr2P7Br material using a theoretical approach. The computed equilibrium structural parameters closely match the relevant experimental counterpart values. The determined elastic constants, obtained under both ambient pressure and hydrostatic pressures up to 18 GPa, satisfy the mechanical stability requirements. Based on the computed Pugh’s ratio, Cauchy pressure, and Poisson’s ratio, it can be concluded that the Sr2P7Br compound exhibits ductile behavior. The polycrystalline elastic moduli, including the isotropic bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio, at ambient pressure and under pressure effects, were derived from the single-crystal elastic constants. Additionally, associated parameters, such as average sound velocity, Debye temperature, minimum thermal conductivity, and Vickers hardness, were examined under pressure influences. The quasi-harmonic Debye approximation was used to investigate the relationship between temperature and some macroscopic physical parameters, such as lattice parameter, bulk modulus, Debye temperature, volume thermal expansion coefficient, and isobaric and isochoric heat capacities, at fixed pressures of 0, 4, 8, 12, and 16 GPa. The results derived from the elastic constants exhibit substantial concordance with those computed using the Debye quasi-harmonic model, thereby validating the reliability of our findings.

The influence of bandgap tunability on the physical features of Rb2LiSbX6 (X=Cl, Br) double perovskites in the context of green technologies

Rubidium-based perovskites have the potential to significantly transform renewable energies by making devices more affordable and environmentally friendly. The DFT is employed to conduct an inclusive analysis of the elastic, structural, electronic structure, transport and optoelectronic properties of Rb2LiSbCl6 and Rb2LiSbBr6. The analysis of tolerance factor, optimization curves and octahedral tilting serves to validate the structural stability. The brittle character of Rb2LiSbCl6 and ductile nature of Rb2LiSbBr6 are substantiated by their mechanical properties. The (W-L) symmetry points for Rb2LiSbCl6 and Rb2LiSbBr6 demonstrate the indirect bandgap of 3.72 eV and 2.9 eV, respectively. A decline in the bandgap is observed upon substitution of the Cl with Br atom. The Kramer-Kronig relations are employed for the assessment of the optical properties, revealing substantial absorption within the UV spectrum for both structures, hence enabling their application in optoelectronics. A wide range of thermoelectric properties are computed utilizing the Boltzmann semi-classical theory. Perovskites possess considerable promise for the implementation of renewable energy applications due to their notable ZT values (i.e., 0.73 for Rb2LiSbCl6 and 0.74 for Rb2LiSbBr6), as well as their enhanced Seebeck coefficients. These characteristics enhance their appropriateness for usage in green technologies.

Insights on structural, elastic, electronic and optical properties under pressure of Cs-Based Fluoroperovskite CsMF3 (M=Ge, Sn, and Pb) compounds.

Insights on structural, elastic, electronic and optical properties under pressure of Cs-Based Fluoroperovskite CsMF3 (M=Ge, Sn, and Pb) compounds.

A Comparative analysis of the physical properties of predicted MAX phases V2SnN and V2SnB with the synthesized V2SnC: Insights from DFT calculations

The Mn+1AXn phases, known for their unique combination of metallic and ceramic properties, have attracted significant attention due to their potential applications in extreme environments. In this study, we use density functional theory to investigate the structural, electronic, elastic, mechanical, and thermodynamic properties of V2SnX (X = B and N) compounds. Our results confirm that both compounds are elastically, thermodynamically, and dynamically stable, with a ductile nature. The metallic behavior is further supported by electronic band structures and density of states analysis, with V-d states playing a key role in electrical conductivity. Using the quasi-harmonic Debye model, we also examine the effects of temperature and pressure, finding that the bulk modulus and Debye temperature decrease with rising pressure below 50 GPa. Based on these findings, V2SnX compounds are ideal candidates for high-performance applications in harsh conditions, where materials need to maintain stability, conductivity, and resistance to thermal and mechanical stress.

First-principles investigation of the structural stability, elastic, and electronic properties of Mg-Al-X (X=Sn, Pb) ternary compounds

In this work, we employed the first-principles calculations to explore the structural stability, elastic modulus, and electronic behavior of the Mg-Al-X (X=Sn, Pb) ternary compounds. The calculated formation enthalpy indicates that the Mg16Al12Sn-C exhibits the best stability with a value of -0.057 eV/atom. Moreover, the Mg16Al12Pb-C possesses the highest modulus values with values of 58.37, 52.32, and 120.86 GPa for bulk, shear, and Young's modulus, respectively. The Mg16Al12Sn-C exhibits weak anisotropy of the lowest AU value of 0.04. Additionally, the Mg16Al12Pb-C possesses the largest melting temperature of 1142.85 K. The high modulus of the Mg16Al12Pb-C can be attributed to the contributions from the Al-Al and Mg-Al bonds. Moreover, the weighted average bond length results show that the Mg16Al12Pb-C (Mg16Al12Sn-C) in the Mg-Al-Pb (Mg-Al-Sn) system possesses the shortest bond length value of 3.067 Å (3.058 Å), resulting in a higher modulus.

A novel Taguchi-based approach for optimizing neural network architectures: application to elastic short fiber composites

This study presents an innovative application of the Taguchi design of experiment method to optimize the structure of an Artificial Neural Network (ANN) model for the prediction of elastic properties of short fiber reinforced composites. The main goal is to minimize the computational effort required for hyperparameter optimization while enhancing the prediction accuracy. By utilizing a robust experimental design framework, the structure of an ANN model is optimized. This approach involves identifying a combination of hyperparameters that provides optimal predictive accuracy with the fewest algorithmic runs, thereby significantly reducing the required computational effort. The results suggested that the Taguchi-based developed ANN model with three hidden layers, 20 neurons in each hidden layer, elu activation function, Adam optimizer, and a learning rate of 0.001 can predict the anisotropic elastic properties of short fiber reinforced composites with a prediction accuracy of 97.71%. Then, external validation of the proposed ANN model was done using experimental data, and differences of less than 10% were obtained, indicating an appropriate predictive performance of the proposed ANN algorithm. Our findings demonstrate that the Taguchi method not only streamlines the hyperparameter tuning process but also substantially improves the algorithm's performance. These results highlight the potential of the Taguchi method as a powerful tool for optimizing machine learning algorithms, especially in scenarios where computational resources are limited. The implications of this study are far-reaching, offering insights for future research in the optimization of different algorithms for improved accuracies and computational efficiencies.

Yield surface of multi-directional gradient lattices with octet architectures

In this paper, a theoretical method is developed to delineate the effective elastic properties and yield surface of the gradient cellular structure. Additionally, a technique is presented for the construction of multi-directional gradient lattices, and two novel tri-directional gradient lattices (TD-GLs) by assembling octet unit cells with side lengths following specified gradient topological parameters serve as an illustrative example. Their effective elastic properties and yield surfaces are systematically investigated with the aid of theoretical, experimental, and finite element methods. It is found that the effective elastic modulus of the proposed TD-GLs exceeds by 48.80% as compared to that of conventional uniform octet lattices. Moreover, the normalized yield surfaces are proposed to emphasize the predominant role of structural topological features by eliminating the influence of the relative density on the yield behavior of TD-GLs, and this method that also can be extrapolated to other tension-dominated lattices. Subsequently, a theoretical model is developed to establish closed-form yield functions for characterizing the yield behavior of TD-GLs. The predicted yield surfaces from the proposed theoretical model demonstrate good agreement with the simulated results. Finally, the proposed TD-GLs demonstrate outstanding yield performance in various directions deviating from their orthogonal principal axes or planes, compared to lattices with uni- or dual-directional gradient topological configurations. In summary, the proposed multi-directional gradient lattices in this study exhibit the exceptional stiffness and outstanding yield performance in various directions, offering valuable insights for the structural design and engineering applications of lattice structures.