Arachis species: High‐quality forage crops—nutritional properties and breeding strategies to expand their utilization and feeding value

Abstract Plants of the genus Arachis originated from South America and are cultivated worldwide. The genus Arachis contains 83 species and nine intrageneric taxonomic sections. The cultivated peanut (Arachis hypogaea L.) belongs to the Arachis section, the forage peanut (Arachis pintoi Krapov. & W. C. Greg.) belongs to the Caulorrhizae section, and the perennial peanut (Arachis glabrata Benth.) belongs to the Rhizomatosae section. These three peanut species have been developed for use as fodder crops. This review summarizes the forage value of Arachis species. Forage and perennial peanuts can be intercropped with forage species to feed livestock. The cultivated peanut vines and peanut by‐products, such as peanut skins and peanut meal, are also high‐quality fodder used to feed sheep, cattle, and poultry. A major limiting factor in terms of adopting forage and perennial peanuts as forage crops is their limited resistance to frosts, resulting from their low winter hardiness. Therefore, the feeding value of cultivated peanuts is higher compared to forage and perennial peanuts. This review suggests that Arachis is a suitable forage crop, focusing on their nutritional properties and breeding to increase their performance under cultivation and feeding value

Titanium Dioxide: From Engineering to Applications

Titanium dioxide (TiO2) nanomaterials have garnered extensive scientific interest since 1972 and have been widely used in many areas, such as sustainable energy generation and the removal of environmental pollutants. Although TiO2 possesses the desired performance in utilizing ultraviolet light, its overall solar activity is still very limited because of a wide bandgap (3.0⁻3.2 eV) that cannot make use of visible light or light of longer wavelength. This phenomenon is a deficiency for TiO2 with respect to its potential application in visible light photocatalysis and photoelectrochemical devices, as well as photovoltaics and sensors. The high overpotential, sluggish migration, and rapid recombination of photogenerated electron/hole pairs are crucial factors that restrict further application of TiO2. Recently, a broad range of research efforts has been devoted to enhancing the optical and electrical properties of TiO2, resulting in improved photocatalytic activity. This review mainly outlines state-of-the-art modification strategies in optimizing the photocatalytic performance of TiO2, including the introduction of intrinsic defects and foreign species into the TiO2 lattice, morphology and crystal facet control, and the development of unique mesocrystal structures. The band structures, electronic properties, and chemical features of the modified TiO2 nanomaterials are clarified in detail along with details regarding their photocatalytic performance and various applications

Rebuilding the Strain Hardening at a Large Strain in Twinned Au Nanowires

Metallic nanowires usually exhibit ultrahigh strength but low tensile ductility, owing to their limited strain hardening capability. Here, our larger scale molecular dynamics simulations demonstrated that we could rebuild the highly desirable strain hardening behavior at a large strain (0.21 to 0.31) in twinned Au nanowires by changing twin orientation, which strongly contrasts with the strain hardening at the incipient plastic deformation in low stacking-fault energy metals nanowires. Because of this strain hardening, an improved ductility is achieved. With the change of twin orientation, a competing effect between partial dislocation propagation and twin migration is observed in nanowires with slant twin boundaries. When twin migration gains the upper hand, the strain hardening occurs. Otherwise, the strain softening occurs. As the twin orientation increases from 0° to 90°, the dominating deformation mechanism shifts from slip-twin boundary interaction to dislocation slip, twin migration, and slip transmission in sequence. Our work could not only deepen our understanding of the mechanical behavior and deformation mechanism of twinned Au nanowires, but also provide new insights into enhancing the strength and ductility of nanowires by engineering the nanoscale twins

Wear Behavior of the Multiheterostructured AZ91 Mg Alloy Prepared by ECAP and Aging

The microstructure design based on the development of heterostructure provides a new way for high strength and ductility Mg alloys. However, the wear property, as an important service performance, of Mg alloys with heterostructure is scarcely investigated. In this work, a high strength and ductility AZ91 Mg alloy with multiheterostructure was prepared via a processing route combined industrial-scale equal channel angular pressing (ECAP) and aging. The multiheterostructure consists of the heterogeneous grain structure and heterogeneous precipitates. The dry sliding wear behavior of this multiheterostructured (MH) alloy is investigated compared to the as-cast alloy. The impacts of the applied load and duration time on the wear volume and coefficient of friction (COF) are analyzed, and the wear mechanism is further discussed. The result indicates that although the MH alloy exhibits high-desirable strength-ductility synergy, it shows a poorer wear resistance but a relatively lower COF compared to the as-cast alloy at the present condition. The wear mechanism of both alloys mainly involves abrasive wear, as well as mild adhesion, delamination, and oxidation. In comparison, the MH alloy shows relatively severe adhesion, delamination, and oxidation. The poor wear resistance of the MH alloy at the present dry sliding wear condition is linked to the abundant grain boundaries and fine precipitates. Therefore, one should reasonably use the MH Mg alloy considering the service conditions to seek advantages and avoid disadvantages

Multimodal Microstructure and Mechanical Properties of AZ91 Mg Alloy Prepared by Equal Channel Angular Pressing plus Aging

Developing cost-effective magnesium alloys with high strength and good ductility is a long-standing challenge for lightweight metals. Here we present a multimodal grain structured AZ91 Mg alloy with both high strength and good ductility, prepared through a combined processing route of low-pass ECAP with short-time aging. This multimodal grain structure consisted of coarse grains and fine grains modified by heterogeneous precipitates, which resulted from incomplete dynamic recrystallization. This novel microstructure manifested in both superior high strength (tensile strength of 360 MPa) and good ductility (elongation of 21.2%). The high strength was mainly attributed to the synergistic effect of grain refinement, back-stress strengthening, and precipitation strengthening. The favorable ductility, meanwhile, was ascribed to the grain refinement and multimodal grain structure. We believe that our microstructure control strategy could be applicable to magnesium alloys which exhibit obvious precipitation strengthening potential

Achieving gradient heterogeneous structure in Mg alloy for excellent strength-ductility synergy

Most metals including Mg alloys have a longstanding dilemma of strength-ductility trade-off, which is hindering their wider applications. In this study, we propose a gradient heterogeneous grain (GHG) structure for evading this trade-off dilemma and ultrasonic severe surface rolling is attempted to construct this novel structure in ZE41 Mg alloy. Here, the GHG structure combine the benefits of gradient structure and heterogeneous grain structure and introduce large microstructural heterogeneities. Compared to the coarse-grain and heterogeneous-grain structured alloys, the GHG structured one exhibits dramatical enhancement in strength, ductility, and strain hardening capability. To the best of our knowledge, its strength becomes much higher than that of common ZE41 Mg alloys at no reduction in ductility. These unique mechanical properties stem from not only the individual contribution of the heterogeneous structure components including the fine/ultrafine grains and deformed coarse grains but also their synergistic effect via hetero-deformation induced strengthening and hardening effects. In summary, our study provides a feasible way to develop new Mg alloys with high strength and good ductility

Coupling Plant Polyphenol Coordination Assembly with Co(OH)₂ to Enhance Electrocatalytic Performance towards Oxygen Evolution Reaction

The oxygen evolution reaction (OER) is kinetically sluggish due to the limitation of the four-electron transfer pathway, so it is imperative to explore advanced catalysts with a superior structure and catalytic output under facile synthetic conditions. In the present work, an easily accessible strategy was proposed to implement the plant-polyphenol-involved coordination assembly on Co(OH)2 nanosheets. A TA-Fe (TA = tannic acid) coordination assembly growing on Co(OH)2 resulted in the heterostructure of Co(OH)2@TA-Fe as an electrocatalyst for OER. It could significantly decrease the overpotential to 297 mV at a current density of 10 mA cm−2. The heterostructure Co(OH)2@TA-Fe also possessed favorable reaction kinetics with a low Tafel slope of 64.8 mV dec−1 and facilitated a charge-transfer ability. The enhanced electrocatalytic performance was further unraveled to be related to the confined growth of the coordination assembly on Co(OH)2 to expose more active sites, the modulated surface properties and their synergistic effect. This study demonstrated a simple and feasible strategy to utilize inexpensive biomass-derived substances as novel modifiers to enhance the performance of energy-conversion electrocatalysis