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Bioenergy is a key strategy for sustainability, yet the potential for biofuel production from chitin is under-exploited. Here, we report the cleavage of the inherently inert σ-type C–C bonds in chitin under the condition of initially breaking the unstable C–O bonds. Mechanistic studies indicate that by regulating the valence state of Ru and the interaction between RuOx and AC-HNO3-melamine, the ability of Ru nanoparticles to cleave C–C and C–O bonds can be controlled. One-pot sequential hydrogenolysis of chitin with RuOx/AC-HNO3-melamine resulted in a mixed alcohol yield 1.66 times that of commercial Ru/C. A mixed alcohol yield of 16.8% was achieved using raw chitin and green process conditions. We expanded the substrate range to include chitosan, N-acetyl- D -glucosamine, and glucosamine. This work demonstrates the potential of shell biorefinery to produce affordable clean energy. [ABSTRACT FROM AUTHOR]

The biobutanol‐based biofuel fermentation is hindered by the challenge of inadequate fermentation broth concentration and the azeotropic systems of water. The application of eucalyptus oil in diesel fuel makes it a promising extractant for biobutanol extraction and dehydration, thus resulting in product recovery and the development of fuel blend technology. Eucalyptus oil‐derived 1,8‐cineole was applied to acetone‐butanol‐ethanol (ABE) and isobutanol systems to enhance the butanol recovery and dehydration. The recovery of n‐butanol and isobutanol reached 92% and 95%, respectively, while the water removal in a 2% butanol system exceeded 99%. These results demonstrated that 1,8‐cineole exhibited a high selectivity toward butanol, thus providing a robust theoretical foundation for the fermentation‐based biofuel recovery and the elimination of azeotropic systems. The introduction of high‐density diesel‐fuel‐like eucalyptus oil into low‐energy‐density biobutanol will increase the energy density of fermentation‐based alcohols, yielding linear and cyclic biofuel blends. [ABSTRACT FROM AUTHOR]

The global economy's digital infrastructure is based on free and open source software. To analyse how firms indirectly collaborate via employee contributions to developer-run projects, we propose a formal definition of 'industrial public goods' – inter-firm cooperation, volunteer and paid labour overlap, and participation inequality. We verify its empirical robustness by collecting networks of commits made by firm employees to active GitHub software repositories. Despite paid workers making more contributions, volunteers play a significant role. We find which firms contribute most, which projects benefit from firm investments, and identify distinct 'contribution territories' since the two central firms never co-contribute to top-20 repositories. We highlight the challenge posed by 'Big Tech' to the non-rival status of industrial public goods, thanks to cloud-based systems which resist sharing, and suggest there may be 'contribution deserts' neglected by large information technology firms, despite their importance for the open source ecosystem's sustainability and diversity. [ABSTRACT FROM AUTHOR]

The effect of Y content on the microstructure of A356 aluminum alloy and the mechanical properties of the alloy under T6 heat treatment was investigated. The results show that with the addition of 0.3 wt.% rare earth Y, the grain size of the cast A356 aluminum alloy reaches a minimum and the mechanical properties reach an optimum. After the T6 heat treatment, the grain structure of the alloy was further reduced and the mechanical properties were further improved. Compared to the cast A356 aluminum alloy without Y, the average α-Al grain size is reduced by 53.4%, the secondary dendrite SDAS by 32.2% and the average length of eutectic Si particles by 82.0%. The ultimate tensile strength (UTS) and elongation (El) increased to 280.75 MPa and 14.43% respectively, and the Vickers hardness increased to 102.9 HV. [ABSTRACT FROM AUTHOR]

In this paper, Cu-Zr alloy powders and materials with different Zr contents were prepared by horizontal stirring high-energy ball milling combined with vacuum hot-pressing sintering. The results show that the mechanical alloying time of Cu-5%Zr, Cu-10%Zr and Cu-15%Zr alloy powder prepared by high energy ball mill is 7 h, 14 h and 22 h, respectively. At the beginning of high-energy ball milling, Zr particles adhere to the Cu matrix and agglomerate phenomenon occurs. With the progress of ball milling, the powder particles become smaller, the Zr particles gradually distribute evenly and widely on the surface of the Cu matrix, and are dissolved in the Cu matrix, and finally alloying is achieved. Cu-Zr alloys with different Zr content are prepared by vacuum hot pressing sintering. When Zr content is 10%, the maximum hardness of Cu-Zr alloy is 277.24HV, which is 462% higher than that of pure copper. [ABSTRACT FROM AUTHOR]

Silicon has the advantages of high specific capacity (4200 mAh/g), low lithium potential and abundant reserves, and is considered to be one of the most suitable materials for replacing graphite negative electrode. However, the commercial silicon particle size is too large to be used directly as an electrode material, and the silicon material will undergo huge volume expansion during the lithium insertion process, resulting in the fragmentation of the active substance falling off from the fluid collector, resulting in a sharp decline in battery capacity. This defect seriously affects the commercial application of silicon-based anode materials. In this paper, a kind of silicon anode material with porous structure is designed for the defect of silicon anode material. The aluminum-silicon alloy prepared by atomization method presents a three-dimensional porous spherical structure after etching, and the abundant holes reserve space for the volume expansion during the process of lithium silicon embedding and improve the transmission rate of lithium ions. It was found that when the silicon content was 12%, the reversible specific capacity of the material was 1269 mAh/g at 4000 mA/g current density, and the capacity retention rate of 100 cycles relative to the fourth cycle was 59.5%. Compared with ball-ground silicon, the capacity retention rate is increased by 25.7%. Therefore, this paper provides a new idea for the design of porous silicon-based anode materials. [ABSTRACT FROM AUTHOR]

This study aimed to address the challenges associated with silicon (Si) anode materials in Li-ion batteries, such as their large volume effect and poor electrical conductivity. To overcome these limitations, a novel composite microsphere called pSi/Ag was developed using quartz waste through a combination of high-energy ball-milling, spray drying, and magnesiothermic reduction techniques. The morphology and structure of the pSi/Ag composite were thoroughly characterized using various methods, including X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The results revealed that the Ag nanoparticles were uniformly dispersed within the porous micron-sized Si sphere particles, leading to enhanced electrochemical performance compared to pure porous silicon that did not undergo the spray drying process. The use of micron-sized Si prevented the excessive formation of the solid electrolyte interphase film, and the pSi/Ag-5 anode, prepared with 5 wt% AgNO3 as a precursor, demonstrated an impressive initial Coulombic efficiency of 92.8%. Moreover, a high specific capacity of 1251.4 mA h g−1 over 300 cycles at a current density of 4000 mA g−1 was attributed to the improved conductivity provided by the Ag nanoparticles in the Si matrix. The straightforward synthesis method employed in this study to produce pSi/Ag presents a promising approach for the future development of high-performance silicon anodes in Li-ion batteries. [ABSTRACT FROM AUTHOR]

Owing to the non-visual characteristics of the shield synchronous grouting engineering, the law of grout filling in the shield tail gap remains obscure. There is a current deficiency in effective three-dimensional filling and diffusion models. Building upon a large-diameter, eight-hole shield tunneling grouting project in Hangzhou, this study aims to construct a holistic three-dimensional model of grout filling in the shield tail gap. Employing COMSOL Multiphysics and grounded on the two-phase Navier–Stokes equations, this study simulated the filling of grouting fluid in the shield tail gap. Utilizing the Brookfield DV3T rheometer, the study ascertained the time-dependent expression of grout viscosity and systematically analyzed the impacts of time-dependent grout viscosity, density, and injection pressure on the filling diffusion morphology, pressure field, velocity field, and the buoyancy experienced by the segmental lining. The results indicate that the injection pressure is positively correlated with the circumferential pressure field of the segmental lining, though the influence on the ring's total buoyancy is minimal. The rate of grout viscosity development significantly affects the overall diffusion morphology: conventional grout tends to be underfilled at the top of the shield tail gap while rapid-setting grout is more likely to be underfilled at the bottom. The grout density is positively correlated with the grout displacement speed and the total buoyancy of the segmental lining. In light of these insights, utilizing low-density, rapid-setting grout under high-pressure grouting for shield tail filling can ensure adequate filling rates while mitigating the adverse effects of segment buoyancy. [ABSTRACT FROM AUTHOR]