Material Characteristics Research Articles

Exploring vacuum foam drying as an alternative to freeze-drying and spray drying for a human lipase

This article compares and explores vacuum foam-drying as an alternative drying technology to freeze-drying and spray drying for a recombinant human lipase as the model protein. Materials characteristics such as structure, surface composition and the solid-state properties of the dry materials were compared and investigated. Moreover, the technical functionality in terms of reconstitution characteristics and the lipase stability were also investigated. The stability of the lipase was evaluated through activity measurements. Sucrose and dextran D40 (40 kDa) were used as matrix former and the surfactant α-dodecyl maltoside was used as surface active additive. The study demonstrated that the drying technique greatly influenced the material structure and composition which in turn affected the reconstitution characteristics. The lipase was overrepresented at the material surface in declining order spray-dried > vacuum foam-dried > freeze-dried. The lipase activity was retained up to 10 % lipase content in solids, but at 20 % lipase a loss of activity was observed for all drying techniques. Phase separation in the solid material may be an explanation. Vacuum foam-drying shows promise as an alternative drying technique for the lipase, and potentially other proteins.

Microstructure evolution modeling of Ti6Al4V alloy during cutting using the Particle Finite Element Method and homogeneous field distributions

This paper aims to explore the evolution of microstructural parameters induced during the cutting of Ti6Al4V alloy (TC4). The microstructure characteristics of the workpiece material is directly tied to its mechanical response during machining. During TC4 cutting, microstructure evolution is observed as a result of severe plastic deformations. The characterization of this phenomenon has significant interest from both academia and industry. In this work we present a developed modeling technique which combines the Particle Finite Element Method (PFEM) with incremental homogeneous field distributions. First, the PFEM is extended to perform a thermo-mechanical analysis capable of capturing the material responses of TC4 during orthogonal cutting. To generate serrated chips, an appropriate strain softening-based constitutive plasticity model i.e., TANH (Hyperbolic TANgent) is utilized. The PFEM’s validity is checked through comparison with available experimental results in terms of chip shapes and cutting forces. Second, the evolution of microstructural parameters such as dislocation density, vacancy concentration, dynamic recrystallization (DRx) grain size, and hardness is incrementally developed and incorporated into the PFEM using internal state variables as homogeneous field distributions. The Johnson–Mehl–Avrami–Kolmogorov (JMAK) model and Hall-Petch equation are applied for predicting grain size and hardness, respectively. The parameters of the corresponding models are modified for TC4 to accurately capture their alterations. Lastly, the predicted results of the microstructure evolution in serrated chips and machined surfaces, including average grain size and hardness, are compared with experiments, demonstrating good agreement. This implies that the PFEM combined with microscale schemes can reliably simulate the machining process of the TC4.

DETERMINATION OF BRIDGE BEAMS SERVICEABILITY USING NON-DESTRUCTIVE TESTING METHODS AND FIELD TESTS

The case of determining the serviceability of bridge beams with manufacturing defects is considered. Based on the results of visual inspection and non-destructive testing, it was found that the defects have a minor impact on the performance of the beams, and the characteristics of the building materials are high. The results of the calculations showed that the beams had almost twice the safety margin compared to the design requirements. The results of field tests of beams showed reliable anchoring of the working reinforcement, proper deformability and crack resistance of the beams. Usage of the acoustic emission method during field tests allowed to establish that the beams had no internal defects that could develop under load and reduce performance. Based on the results of the research, it was concluded that the beams manufactured with defects are suitable for use after the defects have been repaired.

Review of Electrical Steels with their Properties and Recent Trends for Improvement

Objectives: This review study provides a thorough analysis of the magnetic behavior and characteristics of electrical steels, including established and novel materials (3%wt Silicon). Methods: We investigate how composition, microstructure, and processing methods affect the magnetic performance of these steels as well as the basic principles guiding their behavior. Thermomechanical processing can be observed for its impact on the material’s microstructure and magnetic properties. This review discusses testing over samples for conventional processes for different % of cold worked or strain hardening and annealing at higher temperatures i.e., 1200°C. For uncertainties regarding the impact of impurities or inclusions on their magnetic properties, the study was carried out to know the effect of cerium addition on the material’s magnetic properties of the material. Findings: It was observed that rolling temperature has significant effect over magnetic properties of the material. A notable improvement in the magnetic permeability of the material and its critical performance metric for soft magnetic materials is indicated by the increase in “Gamma max”. Similarly, the effects of compressive stresses, doping effect, grain size, annealing, and other manufacturing processes were studied, and observed their impact on magnetic properties. This review discusses the literature on future scope with the latest trends. This helps clarify the trade-offs associated with maximizing electrical steels for certain uses. Novelty: This study presents a novel approach towards electrical steel and its magnetic properties by incorporating different alloying elements and optimizing rolling & annealing parameters. A key innovation is the application of machine learning and neural network to predict and optimize material behavior, core loss and provide methods to improve magnetic properties of electrical steels. Significance: Electrical steels are crucial in transformers and electric motors, enhancing efficiency by minimizing energy losses and improving magnetic performance. This can be achieved by changing manufacturing parameters and operating conditions with the help of latest trends. Keywords: Electrical steel, Magnetic properties, Machine learning, Composition, Microstructure, Core loss

Quantification of fungal biomass in mycelium composites made from diverse biogenic side streams

AbstractMycelium composite materials are comprised of renewable organic substrates interconnected by fungal mycelium, allowing full biodegradability after use. Due to their promising material properties, adaptability, and sustainable nature, these biomaterials are investigated intensively. However, one crucial aspect that has hardly been covered so far is the proportion of fungal biomass in the composites, which would be necessary to assess its contribution to the material characteristics. Since a complete physical separation of mycelium and substrate is not feasible, we approached this issue by isolating the fungal DNA and relating it to the mass of mycelium with the help of quantitative PCR. Overall, 20 different combinations of fungi and biogenic side streams were evaluated for their handling stability, and growth observations were related to the quantification results. Ganoderma sessile was able to form stable composites with almost all substrates, and a positive correlation between mycelial biomass and composite stability could be found. However, the amount of mycelium required for fabricating firm materials strongly depends on the combination of substrate and fungal species used. Less than five mass percent of fungal biomass can suffice to achieve this, as for example when combining Trametes versicolor with sugar beet pulp, whereas a mass fraction of twenty percent leads to crumbly materials when using Pleurotus pulmonarius on green waste. These results indicate that the mycelial biomass is an important factor for the composite’s stability but that the properties of the fungal hyphae, as well as those of the substrate, are also relevant. The presented quantification method not only allows to estimate fungal growth during composite production but can also improve our understanding of how the mycelium influences the material.

Study on Microstructure of Recycled Aggregate Concrete by Scanning Electron Microscopy: A Review

Recycled Aggregate Concrete (RAC) is a new type of concrete made by utilizing waste concrete as aggregate after treatment. With the enhancement of environmental awareness and resource conservation, but the microstructural part of recycled aggregate concrete is not as important as the macro performance enhancement aspect by scholars. And Scanning Electron Microscope (SEM) is a powerful tool for microanalysis, which can provide high-resolution images of samples as well as information on surface morphology and microstructure. In this paper, the micro-structure of RAC will be comprehensively analyzed according to the performance characteristics of RAC materials and the relevant analysis technology of SEM. Based on the microscopic technology of SEM, the research progress of the micro-structure of RAC was carried out, and the morphology and distribution characteristics of recycled aggregate particles, pore structure and porosity, the interface combination between recycled aggregate and cement matrix, and the relationship between micro-structure and RAC properties were summarized, which provided theoretical support for the future understanding of the micro-structure of RAC, increased the understanding of the micro-structure of RAC materials, and more systematically understood the application of microscopic analysis methods in RAC.

Manganese‐Based Composite‐Structure Cathode Materials for Sustainable Batteries

AbstractManganese‐based cathode materials have garnered extensive interest because of their high capacity, superior energy density, and tunable crystal structures. Despite their cost‐effectiveness, challenges like Mn dissolution and gas evolution originating from the irreversible structural degradation pose risks to stability and prolonged electrochemical behaviors, ultimately constraining their practical applications and market prospects. While the material characteristics and redox mechanisms of Mn‐based cathodes are extensively investigated, a systematic iterative approach to material design that balances performance and application demands remains both necessary and urgent. Recent strategies for enhancing cathode performances emphasize the innovative introduction and customization of composite structures in Mn‐based cathode materials to address the challenges above. This review aims to provide a comprehensive understanding of composite‐structure construction methodologies and offers practical guidelines for effectively designing high‐stability Mn‐based composite‐structure cathode materials. This encompasses the classifications of composite scales, the discussions for the extent of composite‐structure construction inside and outside of the cathode grains, and an exploration of the development potential of these materials, especially for grid‐scale applications.

A Progressive Loss Decomposition Method for Low-Frequency Shielding of Soft Magnetic Materials

Energy loss in shielding soft magnetic materials at low frequencies (1–100 Hz) can cause fluctuations in the material’s magnetic field, and the resulting magnetic noise can interfere with the measurement accuracy and basic precision physics of biomagnetic signals. This places higher demands on the credibility and accuracy of loss separation predictions. The current statistical loss theory (STL) method tends to ignore the high impact of the excitation dependence of quasi-static loss in the low-frequency band on the prediction accuracy. STL simultaneously fits and predicts multiple unknown quantities, causing its results to occasionally fall into the value boundary, and the credibility is low in the low-frequency band and with less data. This paper proposes a progressive loss decomposition (PLD) method. Through multi-step progressive predictions, the hysteresis loss simulation coefficients are first determined. The experimental data of the test ring verifies the credibility of PLD’s prediction of the two hysteresis coefficients, improving the inapplicability of the STL method. In addition, we use the proposed method to obtain the prediction results of the low-frequency characteristics of the loss of a variety of typical soft magnetic materials, providing a reference for analyzing the loss characteristics of materials.

Numerical FE Three-phasic Simulation to Predict the Effect of Air Voids on the Dynamic Modulus of Bituminous Composites

In this study, the mechanical performance of bituminous composites was predicted using an upscaling methodology that integrated both finite element analysis and analytical modeling. The FE approach was employed to incorporate intricate geometries and material characteristics. The dynamic modulus of the matrix and the elastic properties of aggregates served as inputs for the numerical models at various scales. This approach considers the distinctive attributes of the granular framework at each level. Furthermore, the investigation involved the influence of air void proportions on the composite's modulus. The numerical models encompassed the random incorporation of air voids within the matrix at varying levels. Notably, it was observed that at low frequencies air voids reduced the dynamic modulus of asphalt more than at high frequencies due to its effect on viscoelastic nature of the bituminous composite. Moreover, heightened temperatures intensified the impact of air void on the dynamic modulus of the asphalt mixture.

Effects of Biological Adhesion on the Hydrodynamic Characteristics of Different Panel Net Materials: A BP Neural Network Approach

Effects of Biological Adhesion on the Hydrodynamic Characteristics of Different Panel Net Materials: A BP Neural Network Approach

A Thermal Impedance Model for IGBT Modules Considering the Nonlinear Thermal Characteristics of Chips and Ceramic Materials

The traditional method of calculating junction temperature does not consider the dependence of a material’s thermal conductivity on temperature, in which the thermal conductivity changes with temperature. However, with an increase in junction temperature, the temperature sensitivity (TS) will have a more significant impact on the actual temperature of chips. This study established an improved IGBT equivalent thermal impedance model that considers the nonlinear characteristics of the TS of chips and ceramic materials. The Fourier series analysis method was used to obtain the heat flux density curve, and then the heat diffusion angles of each layer were solved. Moreover, iterations were performed until the thermal conductivity and temperature of the chip and ceramic layers matched the nonlinear characteristics of the TS. When the power loss was less than 200 W, the maximum error of the junction temperature calculated by the proposed method considering TS was 3%, while the maximum error of the method without considering TS was 9.5%. Compared with the finite element simulation, the proposed method has a faster solving speed and high accuracy. The proposed method only requires the input material parameters, size parameters, and boundary conditions to solve the junction temperature, which has strong practicality and high accuracy.

Using muscle-tendon load limits to assess unphysiological musculoskeletal model deformation and Hill-type muscle parameter choice.

Musculoskeletal simulations are a useful tool for improving our understanding of the human body. However, the physiological validity of predicted kinematics and forces is highly dependent upon the correct calibration of muscle parameters and the structural integrity of a model's internal skeletal structure. In this study, we show how ill-tuned muscle parameters and unphysiological deformations of a model's skeletal structure can be detected by using muscle elements as sensors with which modelling and parameterization inconsistencies can be identified through muscle and tendon strain injury assessment. To illustrate our approach, two modelling issues were recreated. First, a model repositioning simulation using the THUMS AM50 occupant model version 5.03 was performed to show how internal model deformations can occur during a change of model posture. Second, the muscle material parameters of the OpenSim gait2354 model were varied to illustrate how unphysiological muscle forces can arise if material parameters are inadequately calibrated. The simulations were assessed for muscle and tendon strain injuries using previously published injury criteria and a newly developed method to determine tendon strain injury threshold values. Muscle strain injuries in the left and right musculus pronator teres were detected during the model repositioning. This straining was caused by an unphysiologically large gap (12.92 mm) that had formed in the elbow joint. Similarly, muscle and tendon strain injuries were detected in the modified right-hand musculus gastrocnemius medialis of the gait2354 model where an unphysiological reduction of the tendon slack length introduced large pre-strain of the muscle-tendon unit. The results of this work show that the proposed method can quantify the internal distortion behaviour of musculoskeletal human body models and the plausibility of Hill-type muscle parameter choice via strain injury assessment. Furthermore, we highlight possible actions to avoid the presented issues and inconsistencies in literature data concerning the material characteristics of human tendons.

Mechanism analysis on carbon-ash separation of coal gasification fine slag by high internal phase emulsion collector

ABSTRACT Coal gasification slag is a solid waste produced in modern coal chemical industry, its mixed characteristics of residual carbon and ash materials restrict its resource utilization. This study focused on improving the flotation effect of coal gasification slag and reducing the consumption of flotation reagents, a water in oil type high internal phase emulsion collector was prepared, and the microstructure, rheology, stability, particle size and other characteristics of the emulsion collector were analyzed. By comparing with the flotation effect of conventional kerosene collector, when the amount of organic liquid is basically equal, the ash content of the tailings increased by 4.02%, the yield of concentrate increased by 9.79% and the recovery of combustible matter increased by 11.11%. When the combustible matter recovery is similar, the emulsion collector can save 13.40% of kerosene. The flotation kinetics test shows that the emulsion collector can significantly improve the flotation speed. By analyzing the flocculating ability of emulsion collectors, emulsion collectors can significantly improve the flocculating ability of particles, thereby improving the flotation effect. The research results have certain guiding significance for improving the flotation efficiency of coal gasification slag.

Atypical Attack of the Dissimilar Metal Welds of a Water–Water Energetic Reactor Nuclear Power Plant Secondary Circuit: Possible Mechanisms of Failure

ABSTRACTDissimilar metal welds are utilized in the energy industry to connect two materials with different material characteristics. In the case of nuclear power plants, the connected materials tend to be low‐alloyed steel and high‐alloyed material. Despite different material and corrosion properties, under the proper environmental conditions, the used construction materials and weld metals are protected either by a passive layer or by a high‐temperature oxide. Although dissimilar metal welds are used in both primary and secondary circuits, the most frequently documented damage is in the secondary circuit, where, in addition to material heterogeneities, local environmental heterogeneities may form. For dissimilar metal welds in WWER nuclear power plants, a water–water energetic reactor, a subtype of pressure water reactor, we note two main types of attack near the dissimilar fusion boundary: on the carbon steel side or on the high‐alloyed weld metal side (X10CrNiMoN16‐25‐6). The possible causes of the latter “atypical” corrosion attack are debated and can be generalized as a consequence of change of the grain boundary condition.

Mechanical and surface characterisation of additively manufactured polyetheretherketone for the tribo test

Purpose The additive manufacturing process, such as fused filament fabrication based on material extrusion, fabricates the samples layer-by-layer. The various parameters in the process significantly affect the dimensions, structure and mechanical properties of the fabricated parts. The purpose of this paper is to investigate the surface and mechanical properties that can affect the contact characteristics with other materials during tribological tests. Design/methodology/approach The investigation of 3D-printed Polyetheretherketone (PEEK) includes the measurement of dimensions, microhardness, surface roughness, surface energy and tensile strength to define material characteristics. The crystallinity is measured using an X-ray diffractometer to understand the hardness behaviour. Findings The printing parameters affect its surface roughness, hardness and crystallinity. This change in parameters such as layer thickness and infill density impacts mechanical properties such as hardness and surface roughness, which will influence the contact mechanism with the counter body during any tribological test. The change in a single parameter during the sample fabrication and the change in the surface and mechanical properties are observed. Research limitations/implications The material cost plays an important role in conducting numerous destructive tests, which is a major limitation to conducting parameter optimisation by varying more parameters. The study is limited to the as-fabricated samples rather than finished samples and without any heat treatment. Achieving optimal parameters is integral to the success of additive manufacturing, ensuring the production of components with consistent performance. Practical implications The study aims at the application of 3D-printed PEEK for bush or journal bearings that can be directly used in practice. The mechanical properties discussed in this paper can fill the gap between theory and practice. Social implications The research provides all fundamental properties, including the printing parameters and their effect on the dimensions and surface structure, which are required to understand the material and its use. The results are consistent as at least four samples were tested for tribological behaviour. The conclusion is updated as per suggestions. Originality/value The study outlines the relationship between the change in layer thickness and infill density with changes in surface energy, surface roughness, hardness and tensile strength. The deformation and adhesion during the friction test depend on these properties.

A numerical study of Mullins softening effects on mode I crack propagation in viscoelastic solids

This paper presents a finite element analysis of steady-state crack propagation in viscoelastic soft solids exhibiting Mullins softening. A cohesive-zone model is employed to simulate the localized processes at the tip of a Mode I crack in materials governed by viscoelastic behavior and damage-induced Mullins effects. The study numerically evaluates the intrinsic dissipation characteristics of typical rubber-like materials, focusing on the influence of key factors such as Mullins damage, relaxation modulus, and relaxation time. The impact of these factors on material toughening is examined, with particular emphasis on their role in crack propagation. The results reveal that crack propagation velocity is highly sensitive to the interplay between energy dissipation mechanisms. Specifically, Mullins damage parameters are shown to increase fracture toughness by raising the local energy release rate threshold at the crack tip. Additionally, the relaxation modulus enhances viscous dissipation, further elevating this threshold and subsequently reducing crack propagation velocity. Interestingly, an inverse relationship between relaxation time and crack propagation velocity is observed. The study provides a detailed analysis of the dissipation mechanisms at the crack tip, offering valuable insights for improving material toughness.

Temperature Distribution in a Two-Scale Porous Structure of a Catalyst Made of Spherical Particles

The research deals with the determination of the temperature distribution in a two-stage porous catalytic medium when the heat flow passes through. The peculiarity of the proposed model of heat and mass transfer in a porous catalyst is to consider the change in the volume of the spherical particle that makes up the catalyst.A program for calculating the temperature distribution in a two-scale porous structure of a catalyst made of spherical particles that change in volume with time has been developed. It should be noted that the temperature gradient is rather high, and the temperature in the central region of the particle becomes high enough for the process of catalytic reaction initiation only after 3.25 s. The developed program together with analytical and empirical studies allow to find the range of temperature and time of heat treatment at which the given thermophysical characteristics of porous material will be observed.The work will be useful for engineers and scientists studying the problems of thermochemical reactors and heat transfer in catalytic fills.

Advances in Physics and Chemistry of Transition Metal Dichalcogenide Janus Monolayers: Properties, Applications, and Future Prospects

AbstractJanus transition metal dichalcogenides (JTMDs) have garnered significant interest from the scientific community owing to their remarkable physical and chemical features. The existence of intrinsic dipoles makes them different from conventional transition metal dichalcogenides. These properties are useful in various potential applications, including energy storage, energy generation, and other electronic devices. The JTMDs are considered a hot topic in two dimensional (2D) materials research, making it necessary to understand their fundamental properties and potential use in various applications. This review covers the fundamental difference between Janus and conventional transition metal dichalcogenide‐based 2D materials. This discussion encompasses the characteristics of monolayer, bilayer, and multilayer materials, focusing on their structural stability, electronics properties, optical properties, piezoelectricity, and Rashba effects. The impact of external stimuli such as strain and electric field toward engineering the ground state properties of monolayer JTMDs is discussed. Additionally, various potential applications of Janus monolayers, including gas sensors, catalysis, electrochemical energy storage, thermoelectric, solar cells, and field effect transistors, are highlighted, emphasizing enhancing their performance. Finally, the prospects of Janus 2D materials for next‐generation electronic devices are highlighted.

Dynamic regulation of the photothermal conversion performances of nano-enhanced phase change material composited with ceramic foam subjected to external fields

This study aims to comparatively analyze the melting characteristics of magnetic Fe3O4 nano-enhanced phase change materials (NEPCM) assisted by optimum filling strategies of Al2O3 foam ceramics, ultrasonic field and magnetic field under solar radiation. A visualization experimental platform consisting of an ultrasonic field, a magnetic field, and infrared thermography is constructed and used to evaluate in detail the evolution of the melting front, the temperature distribution, and the heat transfer mechanism under different experimental conditions in a square cavity. The results show that the 1 wt% NEPCM using an ultrasonic field has the highest solar energy conversion efficiency of 39.99 % among the 18 experimental groups. This suggests that the cavitation effect and acoustic flow effect induced by ultrasound with a power of 40 W periodic ultrasonic mechanical vibration improve the uniformity of the distribution of magnetic nanoparticles, resulting in improved heat transfer properties. In the experimental group where a magnetic field is applied, the downward movement of the melting interface is accelerated due to the force of the magnetic field on the Fe3O4 nanoparticle. Under the effect of localized porous filling, the solar conversion efficiency of 1 wt% NEPCM is 31.57 % and the total energy storage is as high as 14.39 kJ. With the increase of concentration, the solar conversion efficiency and total energy storage decrease gradually. However, under the simultaneous effect of magnetic field and localized porous filling, the solar conversion efficiency and energy storage show an opposite trend. From a comprehensive point of view, the application of periodic ultrasound with a power of 40 W can effectively improve the photothermal conversion capacity of the PCM.

Looped In Lupus-An Unusual Manifestation

The efficiency of Dye-Sensitized Solar Cells (DSSCs) heavily relies on the structural and morphological characteristics of the photoanode materials [1]. This study investigates the effects of Nitrogen on TiO2 and the subsequent anchoring with two different Azo dyes RP and VC, to evaluate their impact on DSSC performance [2]. A comprehensive analysis was conducted using Scanning Electron Microscopy (SEM) to study the surface morphology of pure TiO2, Nitrogen TiO2 (N-TiO2), and N-TiO2 composites with RP and VC Azo dyes [3]. Energy-Dispersive X-Ray Spectroscopy (EDS) provided insight into the elemental composition and confirmed the successful incorporation of nitrogen into the TiO2 structure. The SEM images reveal significant morphological differences between the pure and N-TiO2 samples, as well as changes induced by the azo dye anchoring [4]. The Nitrogen incorporation was found to increase surface roughness and enhance dye adsorption [5]. A comparative analysis of the N-TiO2 composite with RP and VC azo dyes highlights variations in dye distribution and surface coverage, which may influence light absorption and charge transfer efficiency. The findings provide valuable insights into the design of optimized photoanode materials, aiming to improve the photovoltaic performance of DSSCs [6].