Material Process Research Articles

Activation energies of oxidation in air for SPS-sintered zirconium and its alloys

The research concerns the oxidation process of SPS-sintered zirconium-based materials. The sintered materials are characterized by residual porosity, which can affect the intensification of the oxidation process, compared to melted materials. On the basis of TGA tests carried out at temperatures of 500, 600, 700, and 800 °C, activation energies in air of sintered Zr, Zr–2.5Cu, Zr–2.5Nb, and Zr–2.5Mn, respectively, were calculated. Based on the studies of the microstructure and phase composition of oxidized materials, degradation mechanisms were analyzed for materials after annealing at 700 °C. In sintered Zr, Zr–2.5Cu, and Zr–2.5Nb oxidized at 700 °C, Si3N4 was detected. Si3N4 is formed at the zirconium oxide–zirconium boundary, in oxygen-deficient conditions. Zr–2.5Cu demonstrated the lowest tendency to oxidize despite the low values of activation energy for the oxidation process in air of 61 kJ/mol. This material showed the highest resistance to oxidation in air.

Water-mediated ion transport in an anion exchange membrane

Water is a critical component in polyelectrolyte anion exchange membranes (AEMs). It plays a central role in ion transport in electrochemical systems. Gaining a better understanding of molecular transport and conductivity in AEMs has been challenged by the lack of a general methodology capable of capturing and connecting water dynamics, water structure, and ionic transport over time and length scales ranging from those associated with individual bond vibrations and molecular reorientations to those pertaining to macroscopic AEM performance. In this work, we use two-dimensional infrared spectroscopy and semiclassical simulations to examine how water molecules are arranged into successive solvation shells, and we explain how that structure influences the dynamics of bromide ion transport processes in polynorbornene-based materials. We find that the transition to the faster transport mechanism occurs when the reorientation of water molecules in the second solvation shell is fast, allowing a robust hydrogen bond network to form. Our findings provide molecular-level insights into AEMs with inherent transport of halide ions, and help pave the way towards a comprehensive understanding of hydroxide ion transport in AEMs.

Machine Learning Interatomic Potential for Modeling the Mechanical and Thermal Properties of Naphthyl-Based Nanotubes.

Two-dimensional (2D) nanomaterials are at the forefront of potential technological advancements. Carbon-based materials have been extensively studied since synthesizing graphene, which revealed properties of great interest for novel applications across diverse scientific and technological domains. New carbon allotropes continue to be explored theoretically, with several successful synthesis processes for carbon-based materials recently achieved. In this context, this study investigates the mechanical and thermal properties of DHQ-based monolayers and nanotubes, a carbon allotrope characterized by 4-, 6-, and 10-membered carbon rings, with a potential synthesis route using naphthalene as a molecular precursor. A machine-learned interatomic potential (MLIP) was developed to explore this nanomaterial's mechanical and thermal behavior at larger scales than those accessible through the first-principles calculations. The MLIP was trained on data derived from the DFT/PBE (density functional theory/Perdew-Burke-Ernzerhof) level using ab initio molecular dynamics (AIMD). Classical molecular dynamics (CMD) simulations, employing the trained MLIP, revealed that Young's modulus of DHQ-based nanotubes ranges from 127 to 243 N/m, depending on chirality and diameter, with fracture occurring at strains between 13.6 and 17.4% of the initial length. Regarding thermal response, a critical temperature of 2200 K was identified, marking the onset of a transition to an amorphous phase at higher temperatures.

Study on the Shallow Decay Segment of Gamma-Ray Burst X-Ray Afterglow

Abstract The X-ray afterglow of a certain fraction of gamma-ray bursts (GRBs) comprises a phase of shallow decay. However, the origin of the shallow decay segment is still a mystery. In this paper, we select 103 GRBs that exhibit a shallow decay segment, based on Swift/XRT data prior to 2023 June. We apply the fallback accretion energy external dissipation model to the shallow decay segment in our sample, and find the model can interpret the shallow decay segment within a reasonable range of parameter space. The fallback rate of the progenitor envelope materials onto the accretion disk can reach a peak of 10−7–0.1 M ⊙ s−1 within a time frame of 10–105 s, which is consistent with the typical density profile and spin profile of the progenitor of a GRB. During the fallback process of progenitor envelope materials, progenitor stars of most GRBs have the highest fallback rate at a radius ~1010 cm, which is consistent with the typical radius of a Wolf–Rayet star. The production of shallow decay segments of most GRBs in our sample requires injecting Blandford–Znajek (BZ) energy equal to 10–100 times the kinetic energy of the initial GRB blast wave into the blast wave. However, the shallow decay segment of a few GRBs requires the injected energy to be comparable to the kinetic energy of the blast wave, which means that even if less energy is injected into a GRB blast wave, it is still possible to produce a shallow decay segment. In addition, the peak time of the fallback rate of the progenitor envelope materials is close to the time when BZ energy is injected into the blast wave, which means that the fallback accretion is more active in the initial phase. In summary, our research results provide further support to an external origin for the shallow decay segment in GRBs.

Ion-Ion Structural Correlation and Dynamics of Water in Aqueous NaCl Solutions with a Wide Range of Concentrations.

The behavior of water in concentrated ionic solutions, including supersaturated conditions, is crucial for numerous material and energy conversion processes and fundamental research. All electrolytes whether they "structure-make" or "structure-break" the water structure lead to slower water motion. This study investigates the structure and dynamics of aqueous NaCl solutions across a wide range of concentrations. On the structural side, the primary focus is on ion-ion correlations. In terms of dynamics, we demonstrate that the slowing down of water dynamics continues even beyond the saturated state. We identify three distinct types of dynamics at large concentrations: ballistic, trapped, and diffusive. The van Hove correlation function exhibits no signs of relaxation within a time interval where particle motion is effectively halted. The system displays dynamical heterogeneities, confirmed by evaluating non-Gaussian parameters for the self-part of the van Hove function and identifying the mobile particles. These particles form clusters, with the largest sizes occurring when the non-Gaussian parameters are at their maximum. Additionally, we discuss the relaxation times associated with these systems using the incoherent intermediate scattering function and establish a connection with the mode-coupling theory.

Should the neuropsychoanalytic approach to the mind–body problem be re-framed in terms of transcendental idealism?

ABSTRACT The alignment of neuroscientific research with psychoanalytic theory and practice has led researchers in the emerging field of neuropsychoanalysis to scrutinize their metaphysical assumptions with respect to the relationship between mind and matter. The position which has achieved prevalence is dual-aspect monism. However, this trend is naïve to the fact that no consensus has been reached on the mind–body problem in the philosophy of mind literature. Moreover, like all metaphysical positions, dual-aspect monism contains conceptual flaws and is inconsistently defined, but these issues have not been sufficiently addressed in the neuropsychoanalytic literature. The present study reviews materialism, dual-aspect monism and transcendental idealism as candidate positions on which to ground neuropsychoanalytic thought. Whilst materialism holds that mind is ultimately reducible to material processes and dual-aspect monism holds that mind and matter are two irreducible perspectives on one underlying ontological domain, Kantian transcendental idealism views both mental and physical processes as subjective representations of a numinous reality which cannot be experienced directly. Instances are highlighted where neuropsychoanalytic dual-aspect monism slips into tacit forms of materialism and transcendental idealism. Transcendental idealism is conceived of as an epistemologically modest position which holds that inquiry into the mind–body relationship can only begin through exploring the boundaries of representation. It is submitted that the neuropsychoanalytic approach to the mind–body problem is implicitly aligned with transcendental idealism, and that this should be stated explicitly. Some clinical implications of these variations in metaphysical framing are discussed.

Superhydrophobic and Self-Healing Porous Organic Macrocycle Crystals for Methane Purification under Humid Conditions.

Purifying methane from natural gas using adsorbents not only requires the adsorbents to possess excellent separation performance but also to overcome additional daunting challenges such as humidity interference and durability requirements for sustainable use. Herein, porous organic crystals of a new macrocycle (CaC9) with superhydrophobic and self-healing features are prepared and employed for the purification of methane (>99.99% purity) from ternary methane/ethane/propane mixtures under 97% relative humidity. The high selectivity for methane and water-resistance are attributed to the unique chemical structure of CaC9, possessing an intrinsic 4.2 Å pore along with a pore environment modified with saturated alkyl chains. Besides, CaC9 crystals exhibit a self-healing capacity to realize in situ reconstruction of porosity within 15 min. The transformation of CaC9 crystals from a nonporous state to a porous state can be easily achieved upon treatment with n-hexane vapor, thereby presenting a novel solution to enhance the sustainable separation processes of porous materials. This work introduces a novel molecular-level porous adsorbent for natural gas separation, providing a valuable impetus for designing novel adsorbents with unexpected functions.

Effective Synthesis of Dopamine Dimer.

Dopamine (1) is a commonly used vasopressor, primarily employed to treat various types of shock, congestive heart failure, and acute renal failure. Dopamine dimer (2) is an impurity generated during the production process of dopamine raw materials or the metabolism of dopamine drugs themselves. This article presents an effective method for synthesizing dopamine dimer through the condensation of methyl 3,4-dimethoxyphenyl acetate (4) and 3,4-dimethoxyphenylethyl amine (5), followed by reduction and demethylation. The product was synthesized from easily accessible raw materials, achieving a total yield of 48% over five steps. This synthesis method is simple and beneficial for pharmaceutical companies to adopt and implement.

Interfacial Atomic Mechanisms of Single-Crystalline MoS2 Epitaxy on Sapphire.

The epitaxial growth of molybdenum disulfide (MoS₂)on sapphiresubstrates enables the formation of single-crystalline monolayer MoS₂ with exceptional material properties on a wafer scale. Despite this achievement, the underlying growth mechanisms remain a subject of debate. The epitaxial interface is critical for understanding these mechanisms, yet its exact atomic configuration has previously been unclear. In this study, a monolayer single-crystalline MoS₂ grown on a sapphire substrate is analyzed, decisively visualizing the atomic structure of the epitaxial interface and elucidating its role in epitaxial growth from an atomic perspective. The findings reveal that the interface consists of a periodic molecular MoO3 interlayer, van der Waals epitaxially grown on a single Al-terminated sapphire surface. Additionally, it is discovered that MoO3 coverage enhances surface interactions and introduces a unique atomic arrangement with 1-fold symmetry at the sapphire surface, thereby facilitating the unidirectional alignment of MoS₂. This discovery provides valuable insights into the growth mechanisms leading to single-crystalline MoS₂ formation, and suggests pathways for quantitatively monitoring and controlling growth dynamics, for the improvement of material quality and process repeatability, applicable for single-crystalline MoS₂ or potentially other transition metal dichalcogenides epitaxially grown on sapphire.

Formation of Biofilm and Degradation Processes of Resilient and Green Materials: A Field Study and Novel Perspectives

The surface material’s nature can influence the formation of biofilms. Environmentally friendly materials such as linoleum, derived from organic sources, have emerged to address the need to balance ecological requirements with practical considerations, particularly in sectors where hygiene is of critical importance, such as sports and healthcare. Nevertheless, even with appropriate utilization, these materials can deteriorate over time, resulting in the proliferation of harmful microbes. Metagenomic analyses were conducted to identify the microbiota responsible for the chromatic variation (n = 4) observed on a linoleum sample immersed in water. Subsequently, the data were correlated with spectroscopic analyses via microNIR. The preliminary investigations did not establish the role of abiotic components in the processes of surface discoloration. The bacterial microbiota formed on the surfaces was characterized, indicating a potential biotic role in the degradation of linoleum. Data exploration obtained from the spectroscopic acquisitions through principal component analysis produced a clustering of the data matrix into four subgroups, corresponding to the four chromatic variations. The preliminary data appear to indicate the degradation mechanisms to which materials of organic origin are subject. Furthermore, they suggest that the personalized functionalization of such materials could support effective replacement from a One Health perspective of traditional materials.

Propaganda as a social practice in the UK during the Crimean War

The article analyzes the evolution of information practices in British society during the Crimean War from the point of view of propaganda. The object of the study is the British society. The subject of the study is the change in information practices in connection with the development of scientific and technological progress and military operations. The aim of the study is to identify aspects of the impact of military propaganda on society in the UK at that time and further transform propaganda into social practice. The processing and analysis of factual material is carried out by descriptive, historical, comparative and analytical methods using data from open sources, as well as abstracts and quotations from scientific literature. A stable stereotype of Russia formed during the Crimean War has been revealed, which eventually became part of British heroic mythology, and has multiplied over the past 170 years due to the inclusion of this narrative in the educational program. Conclusions are drawn about the need to take into account the British template vision of Russia and Crimea in the analysis and forecasting. When analyzing and forecasting, take into account the prevailing stereotype common in British society: the archetypal image of Russia as an existential enemy of Britain, both for British elites and for the whole society. The second thing that is extremely important to take into account: for the British, Crimea is a land watered with British blood, despite the fact that the goals of the Crimean War to «wrest Crimea from Russia» were not achieved then. It is for these reasons that the British are supporters and lobbyists of the most radical anti-Russian and anti-Russian policies and practices of the last 10 years.

The effect of material properties and process parameters on die filling using double-tip tooling: A PLS-model-based analysis.

Up-scaling on a rotary tablet press by increasing turret speed can have a negative effect on die filling performance, as the dies have less time to be filled, leading to high tablet weight variability. For this reason, double-tip tooling is investigated, where a punch contains 2 tips instead of 1, doubling the throughput without the need to increase turret speed. However, when using multi-tip punches, one has to bear in mind that punch responses, e.g. pre- and main compression force, are the sum of each tip. When using these responses to assess tablet properties during compression, it is assumed that they can be divided over the total number of punch tips, i.e. an equal contribution of each tip to the response. This assumption can only hold when die filling is uniform across all tips. In this work, the impact of formulation material properties and process settings (X) upon die filling performance for double-tip tooling (Y) was studied, by developing and analyzing a PLS model regressing X versus Y. Additionally, this model enables the estimation of die filling variability based on material characterization data, eliminating the need for extensive tableting experiments and reducing material consumption in R&D.

Simulation and Parameter Optimisation of Edge Effect in Ore Minerals Roll Crushing Process Based on Discrete Element Method

The edge effect is caused by poor use of confinement systems, different roll aspect ratios, operating conditions and other factors, which result in uneven pressure distribution between the two crushing rolls along the roll width direction, affecting the overall roll crushing process. To reduce the edge effect, this paper investigates the simulation of the edge effect and parameter optimisation in the roll-crushing process of ore materials based on the discrete element method (DEM). Firstly, the parameters of the iron ore crushing model are experimentally calibrated, and the working process of HPGR is simulated by DEM. Secondly, the effects of roll speed, roll gap, roll diameter and roll width on edge effect and crushing effect of HPGR are analysed by the one-factor experiment. Finally, the roll pressure optimisation model is established based on the Response Surface Methodology (RSM) to obtain the optimal roll pressure parameters. The results show that, with the roll speed and roll diameter increase, the edge effect also increases, the roll gap shows the opposite trend, and the roll width has less influence. The change in roll diameter has the greatest influence on the crushing effect, roll gap is second, and roll speed and roll width have less influence on the crushing effect. When the feed particles are iron ore with a particle size of 32 mm, the optimisation results show that the edge effect and crushing effect of HPGR are significantly improved when the roll speed is 1.25 rad/s, the roll gap is 38 mm, the roll diameter is 2000 mm and the roll width is 742 mm.

Numerical Simulation of Thermo-Hydro-Mechanical Coupling of Model Test for Nuclear Waste Disposal

This article presents a simulation of a long-term retardation performance Mock-up test of the multi-field coupling of buffer materials, with the aim to study the thermo-hydro-mechanical (THM) processes occurring in the engineered barrier system of a high-level waste (HLW) repository. In view of the theory of mixtures and mechanics of continuous media, the coupled THM mathematical model of unsaturated buffer materials is established, considering heat transport and multiphase fluid flow. Using the buffer material Mock-up test of multi-field coupling as a model, the partial differential equation (PDE) module in the general finite element software COMSOL Multiphysics was developed by a second development stage. The dynamic response process of buffer material under the condition of THM coupling was numerically simulated, and the spatial distribution and variation law of suction, porosity, horizontal displacement, temperature and swelling pressure in the engineered barrier were investigated. The porosity of the buffer material under THM coupling was influenced by the swelling pressure and the suction. The welling pressure evolution of the buffer material may be influenced by the thermal expansion induced by high temperature and the swelling pressure generated by buffer material saturation. The evolution of the horizontal displacement of the heater used to simulate a container with radioactive waste was validated. This paper provides technical reference for the design and safety evaluation of underground laboratory barrier engineering in China.

Constructing the Cretaceous highly silicic plutons in SE China through the magmatic plumbing system

Abstract High-silica plutons (SiO2 > 75wt.%) play a key role in deciphering the evolution and origin of the upper continental crust. Therefore, studying vertical cross sections of high-silica plutons is essential for gaining new insights into magmatic evolution and the thermal and material processes that shape the Earth's crust during pluton formation. In this study, we present extensive data on the bulk-rock geochemistry, zircon U-Pb ages, Hf isotopes, and trace elements for a range of high-silicic rocks from top-to-bottom cross-section in the Jiuzhen batholith and Yunhe pluton in southeastern China. Geochemical and zircon trace element features of the granitic rocks from the Jiuzhen batholith and Yunhe pluton indicate that these high-silica rocks originated from middle- to upper-crustal magma reservoirs via crystal-melt segregation. In the Jiuzhen batholith, the coarse-grained porphyritic granite in the upper unit originated from the reactivation of a pre-existing, highly evolved, water-rich magma reservoir with lower crystallinity, while the coarse-grained porphyritic granite in the lower unit was segregated from the same magma reservoir with higher crystallinity and involved a higher proportion of mantle material in its formation. The fine-grained granite was later extracted from the nearby magma reservoir of coarse-grained porphyritic granite in the upper unit, indicating they were formed through in-situ differentiation of the silica magma reservoir in the shallow crust. Similarly, the geochemical characteristics of granites from different units of the Yunhe pluton suggest they were produced by the solidification of high-silica melts extracted from a common water-poor magma reservoir. As the high-silica magmas accumulated to form a magma reservoir in the shallow crust and subsequently underwent further cooling and crystallization, the proportion of melt decreased, leading to an enrichment of volatiles and silica in the residual melt. The upward migration of these residual melts within the high silicic magma reservoir resulted in vertical compositional variations within the Yunhe pluton. Our research on the Jiuzhen batholith and Yunhe pluton has revealed that the composition of high-silica magmas is influenced not only by crystal-melt segregation within deep magma reservoir but also by in-situ crystal-melt segregation occurring within magma reservoirs formed through the aggregation of felsic melts in the shallow crust.

Resonant enhancement and confinement of microwave field in coupled conductive rod systems

Abstract We investigated the resonant interaction of incident microwaves with a finite linear array of equidistantly arranged conductive rods of finite height. When strong coupling is established between adjacent rods, which act as open resonators for radial waves, a series of resonances emerges, corresponding to the number of rods in the array. Each resonance exhibits distinct charge oscillation amplitudes and phases along the rods, leading to varying radiative losses. Notably, in a system of two resonantly interacting rods, antiphase charge oscillations result in a nearly 30-fold increase in localized field intensity and a quality factor of approximately 400. This study demonstrates the feasibility of creating high-quality open resonators with sub-wavelength confinement, offering the potential for microwave-to-optical conversion and enabling control over quantum processes in materials, thereby broadening their application scope.

Analysis of Causes and Consequences of Failures in Process of Andesite Crushing by Jaw Crusher

Mining and mineral processing are essential for the functioning of many economic sectors and for meeting human needs. Diagnostics and evaluations of faults are necessary to ensure the successful and responsible management of mining and processing processes for mineral raw materials. Fault-free operation contributes to increased efficiency, productivity, safety, and reliability, reduces the cost of the process under consideration, and reduces environmental impacts. This study aims to identify and analyze possible component failures associated with the jaw crusher used in the process of andesite crushing in an open-pit quarry and compare different approaches to their assessment. The benefit of this is using three different failure analysis methods to assess the criticality of individual jaw crusher components. This approach’s novelty lies in the synergy that occurs when assessing the failures’ impacts on safety, quality, and the environment.

A Study on the Fracture of Brittle Heterogeneous Materials Using Non-Extensive Statistical Mechanics and the Energy Distribution Function.

The fracture process of heterogeneous materials is studied here in the framework of the discipline of Non-Extensive Statistical Mechanics. Acoustic emission data provided by an experimental protocol with concrete specimens, plain or fiber-reinforced, under bending are taken advantage of. This innovation of the study lies in the fact that the analysis of the acoustic activity is implemented in terms of the energy content of the acoustic signals rather than of their interevent time or their interevent distance. The Energy Distribution Functions were properly fitted using the expression proposed by Shcherbakov, Kuksenko and Chmelet. This study reveals that the loading and fracture processes of the specific materials are definitely non-additive and non-extensive. It is concluded that the presence of notches is crucial since it assigns non-additivity and non-extensivity from relatively low loading levels due to the early formation of the fracture process zone around the crown of the notch. The values of the Tsallis entropic index, q, that were determined are in very good agreement with the respective ones obtained in previous studies by means of different analysis tools. Finally, a clear correlation between the index q and the average energy content of the acoustic signals is highlighted for the whole range of values of the energy content of the acoustic signals.

Energy-saving aspects of the process of extraction of bioactive compounds from plant raw materials with supercritical fluid solvents

THE PURPOSE. Study of extraction processes of plant raw materials with a wide range of biologically active properties, supercritical carbon dioxide used as a solvent, as well as with the addition of ethanol, used as a co-solvent, to supercritical carbon dioxide in a ratio of 5% to the total consumption at a temperature of 313 K and pressure 30 MPa. METHODS. The study of extraction processes was carried out by the method of supercritical fluid extraction, which is effective and environmentally friendly compared to traditional methods for obtaining extracts. The experimental setup, equipped with two plunger pumps, allowed the implementation of a dynamic extraction method with both supercritical carbon dioxide and carbon dioxide with the addition of ethanol. RESULTS. The final extract yields were obtained for Valeriána officinális, Hypericum, Matricaria and Salvia at a temperature of 313 K and a pressure of 30 MPa using pure carbon dioxide and a carbon dioxide/ethanol mixture as a solvent. Based on the results of experimental data, the dependence of the mass yield of the extract on the extraction time was plotted. This determines the extraction rate of each sample. CONCLUSION. The experimental data obtained indicate that for each of the samples of plant raw materials, the use of supercritical carbon dioxide modified with ethanol in a ratio of 95 and 5%, respectively, leads to an increase in the yield of the extract. This, in turn, leads to a reduction in energy costs when implementing the extraction process using the proposed method on an industrial scale.

Laboratory validation of patient-specific templating for total knee arthroplasty

Patient-specific templating (PST), which is a sister procedure to patient-specific instrumentation (PSI) but hospital-based, is relatively less complex and less expensive than robotics and navigation. However, there are some concerns about the PST including the process of preoperative planning, 3D printing and material, positioning of PST intraoperatively, availability, and clinical value. The purpose of this study was to validate the technical accuracy and reliability of the PST technique in the lab and to report the outcomes of clinical application. To test the reliability of the PST technique, five observers positioned the PST templates five times over the distal femur and proximal tibial whilst a navigation system was used to measure the level of bone cutting, coronal and sagittal alignment, and rotation in both femur and tibia. The mean alignment error in all planes was 0.67° (maximum 2.5°). Concerning the bone (femoral and tibial) cutting, the mean error was 0.32 mm (maximum 1 mm). The qualitative and quantitative analysis showed an overall agreement between observers (p < 0.05). The laboratory part of this study showed that the positioning of the PST over the proximal tibia and distal femur during TKA is reliable. There were statistically insignificant intraobserver and interobserver variations.