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Steelmaking contributes 8% to the total CO2 emissions globally, primarily due to coal-based iron ore reduction. Clean hydrogen-based ironmaking has variable performance because the dominant gas-solid reduction mechanism is set by the defects and pores inside the mm- to nm-sized oxide particles that change significantly as the reaction progresses. While these governing dynamics are essential to establish continuous flow of iron and its ores through reactors, the direct link between agglomeration and chemistry is still contested due to missing measurements. In this work, we directly measure the connection between chemistry and agglomeration in the smallest iron oxides relevant to magnetite ores. Using synthesized spherical 10-nm magnetite particles reacting in H2, we resolve the formation and consumption of wüstite (Fe1-xO)-the step most commonly attributed to whiskering. Using X-ray diffraction, we resolve crystallographic anisotropy in the rate of the initial reaction. Complementary imaging demonstrated how the particles self-assemble, subsequently react, and grow into elongated whisker structures. Our insights into how morphologically uniform iron oxide particles react and agglomerate in H2 reduction enable future size-dependent models to effectively describe the multiscale aspects of iron ore reduction.

Simple and stable generation of monodispersed droplets with volume from picolitre to nanoliter is one of the key factors in high-throughput quantitative microreactors for chemical and biomedical applications. In this work, an efficient method that could realize simple manipulating microflow with a broad operation window for preparing monodispersed droplets with controllable diameter is developed. The microfluidic device is constructed by inserting a capillary with an oblique angle (α) into the continuous phase, named a floating capillary-based open microfluidic device (FCOMD). The transition of droplet-generating mode between dripping and jetting can be achieved by changing capillary number and α. A computational model based on the volume-of-fluid/continuum-surface-force method to explain the controllability of α on the droplet formation regime and droplet breakage, verifying the synergistic effect of ΔP and Fb, facilitates the droplet pinching. A descending order of Pn of capillary with different α is that 45° > 30° > 15° > 60° > 75°, leading to the same order of generated droplet's D. When compared with the traditional capillary co-flow device, the generating throughput of the integrated FCOMD obtained by integrating different numbers of capillaries is at least ten times. Moreover, water in oil, oil in water double-emulsion, colloidal dispersed droplets, and liquid crystal droplets with diameters ranging from 25 to 800 μm are prepared on-demand by the FCOMD, indicating the universality of the microfluidic device. Thus, the FCOMD shows the features of simplicity, practicability, and flexibility, offering valuable guidance for generating controllable droplets with wide size change and showing a great potential application in material science, foods, pharmaceuticals, and cosmetics. [ABSTRACT FROM AUTHOR]

The document discusses the integration of machine learning (ML) into thermal transport research, highlighting its transformative impact on understanding and controlling heat transfer processes. It features 31 papers categorizing ML applications into machine learning potentials, predicting thermal properties, design and optimization, data analysis, and tutorials. ML has enabled accurate simulations, precise property predictions, innovative system designs, and efficient data analysis in thermal transport research, showcasing the potential for further advancements in the field. Despite challenges like model transferability, data scarcity, and interpretability, the document emphasizes the promising future of ML in advancing thermal science and engineering. [Extracted from the article]

Nanotwin structures in materials engender fascinating exotic properties. However, twinning usually alter the crystal orientation, resulting in random orientation and limited performances. Here, we report a well-aligned rutile TiO2 nanotwin film with superior preferential orientation than its isostructural substrate. By means of the synchrotron X-ray Laue nanodiffraction technique, the crystal orientation, twin boundaries, and deviatoric stresses of the film were quantitatively imaged at unprecedented spatial resolution to unravel the underlying mechanism of this anomalous alignment. Massive {101}-type rutile nanotwins were observed, and a crystallographic relationship of the heteroepitaxy was proposed. The rapid twinning and twin-controlled heteroepitaxy are responsible for the texture improvement. This work would open up opportunities for rational design of better twin-based functional materials, and implies the powerful capabilities of X-ray nanodiffraction technique for multidisciplinary applications.

Comprehensive Summary: Deuterium labelling possesses wide applications in pharmaceuticals, chemical science and materials science. Development of efficient methodologies for the synthesis of deuterium labelled compounds, especially hydrogen isotope exchange (HIE), continued to receive an impressive attention over the years. Herein, we developed a nitrogen doped nano‐scale nickel catalyst for deuterium incorporation of a variety of nitrogen heterocycles using D2O as the isotope source. The usefulness of this approach has been demonstrated by 10 g‐scale for complex pharmaceuticals. This methodology represents a practical and scalable deuteration and the air‐ and water‐stable nanocatalyst enables efficient labelling in a straightforward manner. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Deuterium labelling possesses wide applications in pharmaceuticals, chemical science and materials science. Development of efficient methodologies for the synthesis of deuterium labelled compounds, especially hydrogen isotope exchange (HIE), continued to receive an impressive attention over the years. Herein, we developed a nitrogen doped nano‐scale nickel catalyst for deuterium incorporation of a variety of nitrogen heterocycles using D2O as the isotope source. The usefulness of this approach has been demonstrated by 10 g‐scale for complex pharmaceuticals. This methodology represents a practical and scalable deuteration and the air‐ and water‐stable nanocatalyst enables efficient labelling in a straightforward manner. [ABSTRACT FROM AUTHOR]

In recent years, gradient nanotwinned copper, which features dual gradients in twin boundary spacing (TBS) and grain size (GS), has become a focal point of research in the materials science field. This structure has been proven to be an excellent nanotwinned system with a highly controllable microstructural gradient. In this study, a new inverse gradient nanotwinned (IGNT) copper structure model is constructed, where TBS and GS exhibit opposite trends. Molecular dynamics simulations are employed to explore the effect of the TBS gradient on the deformation behavior of this nanomaterial. In this study, it is found that the strength of IGNT copper increases with a larger TBS gradient. By analyzing the microstructural characteristics, it is observed that as the TBS gradient increases, the dislocation density gradually decreases and the fraction of hexagonal close‐packed atoms increases, leading to enhanced material strength. Additionally, with a higher TBS gradient, the appearance of hexagonal close‐packed atomic lines traversing the grains effectively hinders dislocation motion, further improving the material's strength. In this research, new insights are offered into the design of gradient nanotwinned copper structures and important theoretical support and guidance are provided for enhancing the mechanical properties of gradient nanotwinned copper. [ABSTRACT FROM AUTHOR]

Rare-earth-metal-based materials have emerged as frontrunners in the quest for high-performance hydrogen storage solutions, offering a paradigm shift in clean energy technologies. This comprehensive review delves into the cutting-edge advancements, challenges, and future prospects of these materials, providing a roadmap for their development and implementation. By elucidating the fundamental principles, synthesis methods, characterization techniques, and performance enhancement strategies, we unveil the immense potential of rare-earth metals in revolutionizing hydrogen storage. The unique electronic structure and hydrogen affinity of these elements enable diverse storage mechanisms, including chemisorption, physisorption, and hydride formation. Through rational design, nanostructuring, surface modification, and catalytic doping, the hydrogen storage capacity, kinetics, and thermodynamics of rare-earth-metal-based materials can be significantly enhanced. However, challenges such as cost, scalability, and long-term stability need to be addressed for their widespread adoption. This review not only presents a critical analysis of the state-of-the-art but also highlights the opportunities for multidisciplinary research and innovation. By harnessing the synergies between materials science, nanotechnology, and computational modeling, rare-earth-metal-based hydrogen storage materials are poised to accelerate the transition towards a sustainable hydrogen economy, ushering in a new era of clean energy solutions. [ABSTRACT FROM AUTHOR]