Behavior Of Materials Research Articles

Optimization of Film Morphology and Photovoltaic Performance by Employing Asymmetric π-Bridges in Dithienobenzodithiophene-Based Polymer Donors.

Understanding the impact of molecular structure on the molecular packing arrangement and aggregation behaviors of organic semiconductor materials is crucial for investigating their properties in multiple organic photoelectrical applications. In this study, a high-performance polymer donor based on dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene (DTBDT) and 5,6-difluorobenzo[c][1,2,5]thiadiazole (FBT) unit, named PDTBDT-Cl-TFBT, was designed and synthesized by introducing an asymmetric 3-octylthiophene π-bridge between the donor and acceptor segment. The density functional theory (DFT) calculation reveals that the asymmetric π-bridge increases the average dipole moment of the repeating units as well as the configurational disorder in polymer PDTBDT-Cl-TFBT, resulting in the overall diminished self-aggregation and crystallinity, which leads to higher miscibility with the nonfullerene acceptor Y6 than that of the symmetric π-bridge-modified polymer PDTBDT-Cl-DTFBT. This feature leads to a suitable phase separation in the PDTBDT-Cl-TFBT:Y6 blend and contributes to better photovoltaic performance. As a result, organic solar cells (OSCs) based on PDTBDT-Cl-TFBT:Y6 achieve a notably higher power conversion efficiency (PCE) of 14.13%, surpassing the performance of that based on PDTBDT-Cl-DTFBT:Y6 (9.63%). Detailed analyses indicate that the performance enhancement is primarily attributed to the reduced trap density, mitigated energetic disorder, improved charge transport, and suppressed charge recombination. This research uncovers an effective strategy for optimizing the film morphology and photovoltaic performance of DTBDT-based polymer donors.

In Vitro Evaluation of the Fracture Strength among Three Different Denture Base Materials

Failure in the form of denture fracture is commonly encountered by both removable prosthodontics wearers and dentists, it is mainly attributed to material properties, technical features, stresses while in function or due to impact as a consequence of dropping the dentures. Traditionally, Heat-Polymerized Polymethylmethacrylate (PMMA) has been the gold standard for denture bases due to its ease of processing and acceptable mechanical properties. However, newer materials, injectable flexible nylon-based resin and CAD/CAM Polyether ether Ketone (PEEK) denture bases are being introduced with claims of superior strength and durability. The aim of this study was to investigate the fracture strength of three commonly used denture base materials in Libya, which may aid in selecting the best material for a given application and predicting potential material behavior under load when holding the durability of the material in mind. A total of 36 samples were tested. These samples were divided into three groups, with 12 samples each: Group I heat polymerized acrylic resin PMMA, group II Injectable flexible nylon-based resin and group III CAD/CAM (PEEK). The fracture strength test was carried out on a universal testing machine at a crosshead speed of 5 mm/min. The results were analyzed using ANOVA, and multiple comparisons were undertaken using Tukey’s HSD test. Statistical significance was set at P ≤ 0.001. The result of this study shows there were significant differences in the fracture strength among the three groups (P< 0.001). Moreover, CAD/CAM (PEEK) denture base material exhibited significantly the highest fracture strength (234.17N ± 13.5) whereas the least fracture strength value was measured with Injectable flexible nylon-based resin denture base material (75.25N±10.5). The study concluded that, within the limitations of this study, the results demonstrate that CAD/CAM (PEEK) outperforms Injectable flexible nylon-based resin and heat polymerized acrylic denture base materials in terms of the fracture strength, supporting its potential as an advanced material for denture construction. However, further clinical studies are recommended.

Achieving High Quality Factor Interband Nanoplasmonics in the Deep Ultraviolet Spectrum via Mode Hybridization.

Interband plasmons (IBPs) enable plasmonic behavior in nonmetallic materials, such as semiconductors. Originating from interband electronic transitions, IBPs are characterized by negative real permittivity that can extend into deep ultraviolet (DUV) spectrum, as demonstrated using silicon. However, the practical applications of IBPs are limited by their inherently broad resonances. In this study, we address this limitation by hybridizing the localized plasmon resonance of silicon nanostructures with the Fabry-Pérot resonance of a SiO2 dielectric layer atop a silicon substrate. This design achieves a simulated quality factor (Q-factor) of ∼43, with experimental measurements yielding a Q-factor of 37 at ∼4.6 eV within the DUV region. Furthermore, we demonstrate a 5.4-fold enhancement in DUV absorption for lignin-modified polyethylene glycol films when integrated with the hybridized DUV cavity, showcasing the potential for UV blocking applications. Our findings offer a versatile platform that can be adapted to other IBP systems and open new opportunities in UV-specific applications.

Numerical Modal Analysis of Foams with Different Types and Configurations

Thanks to the perfect combination of mechanical properties like high strength and rigidity with functional properties like thermo-acoustic insulation and vibration damping, foam structures are becoming increasingly attractive in engineering applications. Most of the research done so far has been focused on the mechanical properties of foams. On the other hand, understanding the vibration behavior of foams is vital since most failures in engineering applications are associated with violent vibrations. In this research, it is focused on the vibration analysis of foams with different types and configurations. In the context of vibration, modal analysis is a highly preferred method for fully understanding the structural behavior of materials. The Finite Element Method is commonly employed for numerical modal analysis to reveal the vibration characteristics of structures, including natural frequencies and corresponding mode shapes. With this objective, the natural frequencies and mode shapes of these foams were defined under both clamped-free and free-free boundary conditions. Subsequently, the effects of material application and boundary conditions were examined. The findings and results obtained can provide valuable insights to researchers and engineers for design applications.

Predictive models for the surface roughness and subsurface damage depth of semiconductor materials in precision grinding

Abstract Workpiece rotational grinding is widely used in the ultra-precision machining of hard and brittle semiconductor materials, including single-crystal silicon, silicon carbide, and gallium arsenide. Surface roughness and subsurface damage depth (SDD) are crucial indicators for evaluating the surface quality of these materials after grinding. Existing prediction models lack general applicability and do not accurately account for the complex material behavior under grinding conditions. This paper introduces novel models for predicting both surface roughness and SDD in hard and brittle semiconductor materials. The surface roughness model uniquely incorporates the material’s elastic recovery properties, revealing the significant impact of these properties on prediction accuracy. The SDD model is distinguished by its analysis of the interactions between abrasive grits and the workpiece, as well as the mechanisms governing stress-induced damage evolution. The surface roughness model and SDD model both establish a stable relationship with the grit depth of cut (GDC). Additionally, we have developed an analytical relationship between the GDC and grinding process parameters. This, in turn, enables the establishment of an analytical framework for predicting surface roughness and SDD based on grinding process parameters, which cannot be achieved by previous models. The models were validated through systematic experiments on three different semiconductor materials, demonstrating excellent agreement with experimental data, with prediction errors of 6.3% for surface roughness and 6.9% for SDD. Additionally, this study identifies variations in elastic recovery and material plasticity as critical factors influencing surface roughness and SDD across different materials. These findings significantly advance the accuracy of predictive models and broaden their applicability for grinding hard and brittle semiconductor materials.

Sequential Stimuli-Response System of Eu-MOF Isomers.

Multiple stimuli-responsive materials hold excellent potential for the next generation smart materials owing to their unique response to external stimuli, providing a powerful impetus for the development of intelligent optical devices. The stimuli-responsive behavior of common multiple stimuli-responsive materials are independent of each other, causing the lack of multiplicity and identification for information technology, which is easy to decode. Herein, QIPA-Eu-1 and QIPA-Eu-2 isomers were prepared from QIPA and EuCl3·6H2O in different solvent thermal conditions for building sequential stimuli-response (SSR) system. Solvent-driven structural transformations of the isomers into QIPA-Eu-3 occurred, along with color change and fluorescence emission variation ascribed to the generation of QIPA aggregates. Furthermore, QIPA-Eu-3 displayed excellent photochromic behaviors. Combining theoretical calculation with well-defined experiments to reveal the mechanism, it was found that light drove the change in the dihedral angles between the quinoline nucleus and adjacent benzene rings in QIPA aggregates. Finally, on the basis of sequential stimuli-induced stepwise responsive behavior of QIPA-Eu-1, the sequential logic gate and time-dependent fluorescence dynamic anti-counterfeiting pattern were successfully constructed. This study provided a new perspective for design and construction of SSR system, which showed promising potential in the fields of data transmission and information encryption.

Simulation-based high-speed elongational rheometer for Carreau-type materials

Abstract For the simulation-based design of fiber melt spinning processes, the accurate modeling of the processed polymer with regard to its material behavior is crucial. In this work, we develop a high-speed elongational rheometer for Carreau-type materials, making use of process simulations and fiber diameter measurements. The procedure is based on a unified formulation of the fiber spinning model for all material types (Newtonian and quasi-Newtonian), whose material laws are strictly monotone in the strain rate. The parametrically described material law for the elongational viscosity implies a nonlinear optimization problem for the parameter identification, for which we propose an efficient, robust gradient-based method. The work can be understood as a proof of concept, a generalization to other, more complex materials is possible.

Nanoindentation and deformation behaviors of α$\alpha$‐Al2O3${\rm Al}_2 {\rm O}_3$: A molecular dynamic study

AbstractStudying the nanoindentation behavior of materials at the atomic level is crucial for advancing technologies involving energetic atom bombardment, ion implantation, and nanomechanical testing. Using molecular dynamics simulations with two typical rigid ion interatomic potentials (fixed charges), we showed that the mechanical responses and dislocation nucleation of alumina (‐) are highly temperature‐ and orientation‐dependent. The complex behavior in dislocation dynamics has been rationalized by computing the distribution of stacking fault energy. It is further found that SHIK potential provides better accuracy in describing dislocation dynamics at a much lower computational cost.

Signal Correction for the Split-Hopkinson Bar Testing of Soft Materials

The Split-Hopkinson pressure bar (SHPB) test is a commonly accepted experiment to investigate the material behavior under high strain rates. Due to the low impedance of soft materials, here, the test has to be performed with plastic bars instead of metal bars. Such plastic bars have a certain viscosity and require a correction of the measured signals to account for the attenuation and dispersion of the transmitted waves. This paper presents a signal correction method based on a spectral decomposition of the strain-wave signals using Fast Fourier Transform and additional applied strain gauges in the experimental setup. The concept can be used to adapt the pulses and to concurrently validate the measurement method, which supports the evaluation of the experiment. Our investigation is carried out with a Split-Hopkinson pressure bar setup of PMMA bars and silicon-like specimens produced by the 3D printing process of digital light processing.

The Optimization of Rotary Bending Die Process: Criteria for the Metal Sheet Angles and Springback Effects

Rotary die bending enables the precise fabrication of sheet metal components across various bending angles, offering high dimensional accuracy, structural stability, and reduced springback. This study employs explicit and implicit numerical simulations using the Abaqus software to analyze the rotary die bending process and springback behavior of SUS304 stainless steel sheets. Five key criteria are investigated: desired angle post-springback (asi), springback factor (ksi), forming stress (Von Mises) at the required bending angle (Sr), residual stress (Von Mises) after springback (Sb), and equivalent plastic strain (PEEQ). These criteria enable accurate predictions of material behavior during rotary die bending, including elastic-plastic deformation and stress distribution. The insights gained support a more flexible design process, enhance the precision of sheet metal bending, and ensure that the final product meets the specified requirements. This research serves as a valuable reference for professionals working with sheet metal components made from various metals and bimetal sheets. Additionally, it informs strategies to mitigate or eliminate residual stress in bent parts, improving reliability and manufacturability.

Environmental release behavior, cell toxicity and intracellular distribution of novel biodegradable plastic materials.

In response to the increasingly severe issue of plastic waste, biodegradable plastics have garnered extensive attention as a potential alternative to traditional plastics. Among these materials, biodegradable plastics hold a dominant position. The objective of this study was to assess the environmental risks of five commercially available biodegradable plastics: polyglycolic acid (PGA), polylactic acid (PLA), poly(butylene succinate) (PBS), poly(butylene carbonate) (PBC), and poly(butylene adipate-co-terephthalate) (PBAT). The evaluation included their physical properties, microplastic release behavior, and cytotoxicity. In addition, the effect of age process on the environmental behavior of biodegradable plastic materials was further investigated. The results revealed that PGA and PBS exhibited lower risks in terms of microplastic release, whereas PLA demonstrated higher environmental mobility. Further cytotoxicity experiments indicated that PLA and PBS exerted significant toxic effects on human cell lines, including human normal liver cells (LO2), human monocytic leukemia cells (THP-1), human umbilical vein endothelial cells (HUVECs), and human colon carcinoma cells (Caco-2). Additionally, this study utilized Nile Red labeling to observe the co-culture system of PGA with THP-1cells, uncovering that THP-1cells gradually engulfed and internalized PGA microplastics over time. This finding provides new insights into the potential mechanism by which microplastics promote cell proliferation. Moreover, we also found that the aging process partially reduced the cytotoxicity of PGA, but had little effect on environmental mobility. Considering the comprehensive research findings, PGA is considered an ideal material for large-scale applications due to its low cytotoxicity and environmental risks. In contrast, the environmental safety of other types of plastics requires more comprehensive risk assessment to determine their suitability. This study provides significant scientific evidence for the environmental impact assessment of biodegradable plastics and plays a crucial role in promoting the development of sustainable plastic alternatives.

Alveolar ridge preservation with autogenous tooth graft: A histomorphometric analysis of 36 consecutive procedures.

The aim of this study was to analyze the histomorphometric findings of autogenous tooth grafting (ATG) for alveolar ridge preservation (ARP), using graft material from extracted teeth. Variations by sex, age and location of extracted teeth, as well as any associated complications, were also assessed. This prospective, single-cohort study was conducted using ATG placed in extraction sockets. After 5 months healing, bone biopsies were collected during implant placement and analyzed histomorphometrically to assess new vital bone, residual biomaterial, and connective tissue. The results underwent statistical analysis; non-parametric tests (Mann Whitney test for independent samples and the Kruskal-Wallis test) were applied. 27 patients (16 females, 11 males) underwent 36 ARP procedures. Histomorphometric analysis revealed a mean percentage of new vital bone of 29.14 % ( ± 10.86), residual tooth graft of 10.84 % ( ± 6.82), and intertrabecular connective tissue of 59.87 % ( ± 10.56). No significant differences were found in relation to age, sex or location. ATG appears to be a promising material for ARP, without significant complications. Further comparative studies are needed to better understand this material's behavior.

Efficient and accurate determination of crack propagation rate without unloading-induced crack closure

Efficient and accurate determination of crack propagation rate without unloading-induced crack closure

Analytical and Numerical Comparison of the Two-Dimensional One-and Two-Phase Energy Storage Phenomenon in Phase Change Materials

Abstract This work investigated the thermal behavior of phase change material during the melting process in a two-dimensional (2D) plate intended for thermal energy storage. The analytical and numerical analyses were conducted for both one phase and two-phase systems. The numerical analysis was conducted using the Mathematica program, while the COMSOL Multiphysics program, which employs the finite element approach, was employed. To validate the numerical analysis answers, the Stefan-Neumann equations were solved analytically using the EES (Engineering Equation Solver) program. The present study investigated the temporal variation of heat transfer flow during the melting process of paraffin material under a constant wall temperature. A 98.9% agreement is seen between the regression analysis findings of the one-phase numerical and analytical solutions for the melting distance of paraffin from the wall in different time periods (0.8–16 h). This study examined the numerical and analytical solutions for one- and two-phase systems and found that the thermal energy storage values converged to 99.2% for two phase systems and 99.6% for one phase systems.

Thermal data from Málaga's historical centre: Surface and air temperature measurements captured via mobile station and thermal imaging.

This dataset contains air and surface temperature measurements taken twice daily at 11:00 and 23:00 GMT+2 from 24th June to 5th July 2024 (a total of 10 days) in the historical centre of Malaga, Spain. It includes detailed thermal readings from various street materials and the facades of historical buildings, offering insights into the thermal properties and responses of these elements at different times of day. This dataset provides valuable information on localized temperature variations within the historical centre, influenced by different materials and architectural styles. It can be used to model microclimate variations, evaluate the thermal behavior of both historical and contemporary materials, and inform urban planning and heritage conservation efforts.

A Numerical Model for Predicting the Smoldering Behavior of Bio-based Insulation Materials: Model Theory and Validation

A Numerical Model for Predicting the Smoldering Behavior of Bio-based Insulation Materials: Model Theory and Validation

Diffusion behavior of phase change materials at the interface of aged asphalt binder based on molecular dynamics simulation and experimental analysis

Diffusion behavior of phase change materials at the interface of aged asphalt binder based on molecular dynamics simulation and experimental analysis

A review on structural configuration and constitutive material behavior of rail tracks in finite element modeling

A review on structural configuration and constitutive material behavior of rail tracks in finite element modeling

Process optimization for coaxial extrusion-based bioprinting: A comprehensive analysis of material behavior, structural precision, and cell viability

Process optimization for coaxial extrusion-based bioprinting: A comprehensive analysis of material behavior, structural precision, and cell viability

Study on the Corrosion Behavior of Graphite Materials in Molten CuSn Alloy

Graphite, a critical material for furnace walls, is pivotal to the reliability of the carbon-free hydrogen production industry through methane pyrolysis catalyzed by molten metals. This study systematically investigates the corrosion behavior of molten CuSn alloy on three typical commercial graphite materials—low-density graphite (LDG), high-density graphite (HDG), and pyrolytic graphite (PyG)—with a focus on their corrosion resistance and the underlying mechanisms responsible for graphite corrosion over a period of up to 1000 h at 1100 °C. The experimental results show that LDG suffered the most severe corrosion, with a mass loss of up to 60.09% and a hardness decrease from 0.73 GPa to 0.17 GPa, whereas PyG demonstrated the best corrosion resistance, with only a 5.64% mass loss and a hardness drop from 0.52 GPa to 0.35 GPa. SEM and XRD analyses revealed that the porous structures of LDG and HDG suffered significant macroscopic corrosion, caused by the stress from molten metal infiltration and aggregation in the pores, leading to structural collapse. Interestingly, all three types of graphite, including the non-porous PyG, exhibited disordered microstructural degradation as detected by Raman spectroscopy. Molecular dynamics (MD) simulations confirmed that the thermal motion of Cu and Sn atoms primarily drives the microstructural corrosion of graphite, suggesting that the corrosion process involves both micro- and macro-level damage. These findings provide crucial insight into the compatibility of different graphite materials with molten CuSn alloy and valuable guidance for material selection in methane pyrolysis devices.