The increase in strength usually accompanies by the sacrifice of ductility in the composites. This work proposed a strategy of design and synthesis of in-situ TiB2 particles to effectively tailor the ...microstructures and to enhance the mechanical performance of Al–Si-based composites. The tuning mechanisms for size and morphology of TiB2 particles were investigated by combustion synthesis in the Al–Ti–B reaction system. The nano/submicron-sized TiB2 particles with desirable morphology were then specially selected to construct high-performance Al–Si-based composites. Thanks to the strong interface bonding with a low crystallographic mismatch, TiB2 particles significantly refined the primary α-Al dendrites, eutectic Si and θ’ precipitates in the composites, which were 79.2%, 51.9% and 37.6% respectively smaller than those of the matrix. Numerical modeling results suggested that submicron-sized TiB2 particles were more likely to be engulfed or serve as heterogeneous sites while nano-sized TiB2 particles would be repulsed to the solid/liquid interface to physically restrict the growth of α-Al dendrites. The strength-ductility trade-off dilemma was broken therefore superior mechanical properties were obtained in the composites. This work provides a novel perspective for manipulating Al–Si-based alloys in terms of avoiding poisoning and achieving microstructural refinement and outstanding strength-ductility synergy.
•Novel TiB2 particles were designed and synthesized to enhance the performance of Al–Si-based composites.•The size and morphology tuning mechanisms of in-situ TiB2 particles are revealed in the Al–Ti–B reaction system.•Nano/submicron-sized TiB2 particles exert strong interface bonding and low crystallographic mismatch with Al–Si matrix.•By optimizing the spatial distribution of TiB2 particles, composites outstanding strength-ductility synergy are achieved.
Disruption of circadian (daily) timekeeping enhances the risk of metabolic syndrome, obesity, and type 2 diabetes. While clinical observations have suggested that insulin action is not constant ...throughout the 24 hr cycle, its magnitude and periodicity have not been assessed. Moreover, when circadian rhythmicity is absent or severely disrupted, it is not known whether insulin action will lock to the peak, nadir, or mean of the normal periodicity of insulin action.
We used hyperinsulinemic-euglycemic clamps to show a bona fide circadian rhythm of insulin action; mice are most resistant to insulin during their daily phase of relative inactivity. Moreover, clock-disrupted Bmal1-knockout mice are locked into the trough of insulin action and lack rhythmicity in insulin action and activity patterns. When rhythmicity is rescued in the Bmal1-knockout mice by expression of the paralogous gene Bmal2, insulin action and activity patterns are restored. When challenged with a high-fat diet, arhythmic mice (either Bmal1-knockout mice or wild-type mice made arhythmic by exposure to constant light) were obese prone. Adipose tissue explants obtained from high-fat-fed mice have their own periodicity that was longer than animals on a chow diet.
This study provides rigorous documentation for a circadian rhythm of insulin action and demonstrates that disturbing the natural rhythmicity of insulin action will disrupt the rhythmic internal environment of insulin sensitive tissue, thereby predisposing the animals to insulin resistance and obesity.
► Insulin action shows a bona fide circadian rhythm ► Mice are most resistant to insulin during their daily phase of relative inactivity ► Disruption of circadian clocks predisposes animals to insulin resistance and obesity ► Function of insulin sensitive tissue depends upon the rhythmic internal environment
Solid-state nanopores as a versatile alternative to biological nanopores have grown tremendously over the last two decades. They exhibit unique characteristics including mechanical robustness, ...thermal and chemical stability, easy modifications and so on. Moreover, the pore size of a solid-state nanopore could be accurately controlled from sub-nanometers to hundreds of nanometers based on the experimental requirements, presenting better adaptability than biological nanopores. Two-dimensional (2D) materials with single layer thicknesses and highly ordered structures have great potential as solid-state nanopores. In this perspective, we introduced three kinds of substrate-supported 2D material solid-state nanopores, including graphene, MoS
and MOF nanosheets, which exhibited big advantages compared to traditional solid-state nanopores and other biological counterparts. Besides, we suggested the fabrication and modulation of 2D material solid-state nanopores. We also discussed the applications of 2D materials as solid-state nanopores for ion transportation, DNA sequencing and biomolecule detection.
Summary
Balancing domain decomposition by constraints algorithms with adaptive primal constraints are developed in a concise variational framework for the weighted plane wave least‐squares ...discretization of Helmholtz equations with high and various wave numbers. The unknowns to be solved in this preconditioned system are defined on elements rather than vertices or edges, which are different from the well‐known discretizations such as the classical finite element method. Through choosing suitable “interface” and appropriate primal constraints with complex coefficients and introducing some local techniques, we developed a two‐level adaptive balancing domain decomposition by constraints algorithm for the plane wave least‐squares discretization, and the condition number of the preconditioned system is proved to be bounded above by a user‐defined tolerance and a constant that is only dependent on the maximum number of interfaces per subdomain. A multilevel algorithm is also attempted to resolve the bottleneck in large‐scale coarse problem. Numerical results are carried out to confirm the theoretical results and illustrate the efficiency of the proposed algorithms.
TiAl-5wt.%Ti2AlC-3wt.%Mn composites reinforced by the addition of Mn and in situ synthesized Ti2AlC nanoparticles with a novel microstructure were fabricated. The microstructure and compressive ...properties of the fabricated composites were thoroughly investigated. The interface between the nanoparticles and the TiAl matrix maintained a very small mismatch and exhibited a stable combination, leading to noticeable grain refinement in the fabricated composites. Furthermore, the yield strength, maximum compressive strength, fracture strain, and strength-ductility balance of the TiAl-5wt.%Ti2AlC-3wt.%Mn composites increased by 30.7%, 10.1%, 5.5%, and 9.9%, respectively, compared with those of the TiAl alloy. The mechanisms by which the properties of the composites were improved mainly thermal mismatch strengthening, Orowan strengthening, grain refinement strengthening, and solid solution strengthening.
•In-situ Ti2AlC particles and Mn evolved TiAl alloy into a refined microstructure.•The interface between the TiAl matrix and nanoparticles exhibited a stable combination.•Toughness and strength of TiAl composites were significantly elevated by 9.9% and 30.7%.•The dominant ones were the thermal mismatch and the Orowan strengthening mechanism.
Due to rapid degradation of the newly filled municipal solid waste (MSW), the local temperature of the waste layer increases greatly. The mechanical parameters related to waste degradation and the ...deformation of high-density polyethylene (HDPE) pipes in the waste body will be affected by the elevated temperature. To predict the temperature distribution in the anaerobic landfill, a one-dimensional heat transfer model is established in this study. This model considers the stratification of the saturated and unsaturated zones, and the layering of new and old waste. Furthermore, a single peak model for heat production is applied as the source term of heat production. The stratification of the unsaturated and saturated zones is considered by distinguishing the difference in heat conductivity and specific heat capacity. The layering of the new and old waste layers is considered by distinguishing the difference in the length of time that waste has been degraded to produce heat. Based on the numerical calculation method, the temperature distribution in a landfill with layered new and old MSW is well simulated. The position where the maximum temperature occurs and the variation in the temperature at the edge of new and old waste are elucidated. The sensitivity analysis shows that the influence of the density on the temperature distribution is more significant. Besides, the stratification of saturated-unsaturated waste should also be considered in landfills.
Tuning solidification microstructure remains a grand challenge for ceramic particles reinforced Al-Si based composites due to adverse interactions between ceramic particles and Si-containing melts. ...This work proposed a novel in-situ synthesis strategy of designing master alloys decorated with well-dispersed TiCxNy and TiB2 particles to synergistically optimize the Al-Si based composites. By adjusting the reactant contents and ratios, near-spherical nano-sized TiCxNy particles and hexagonal submicron-sized TiB2 particles were obtained in as-synthesized Al-(TiCxNy-TiB2)p master alloys. The effects of this pre-dispersed agent on solidification kinetics, microstructure features and mechanical performance evolution of the Al-10Si-2Mg composites were investigated in detail. TiCxNy-TiB2 particles could trigger the heterogeneous nucleation of primary α-Al crystals, and the growth-restricting effects also contributed to grain refinement, which finally accounted for the enhancement in both strength and ductility. This work is expected to provide new guidance for selection of reinforcing particles and synergistic optimization of the solidification microstructure and performance.
Neuromorphic computing has become an increasingly popular approach for artificial intelligence because it can perform cognitive tasks more efficiently than conventional computers. However, it remains ...challenging to develop dedicated hardware for artificial neural networks. Here, a simple bilayer spintronic device for hardware implementation of neuromorphic computing is demonstrated. In L11‐CuPt/CoPt bilayer, current‐inducted field‐free magnetization switching by symmetry‐dependent spin–orbit torques shows a unique domain nucleation‐dominated magnetization reversal, which is not accessible in conventional bilayers. Gradual domain nucleation creates multiple intermediate magnetization states which form the basis of a sigmoidal neuron. Using the L11‐CuPt/CoPt bilayer as a sigmoidal neuron, the training of a deep learning network to recognize written digits, with a high recognition rate (87.5%) comparable to simulation (87.8%) is further demonstrated. This work offers a new scheme of implementing artificial neural networks by magnetic domain nucleation.
The dominant mode of field‐free magnetization switching in L11‐CuPt/CoPt bilayer is demonstrated to be domain nucleation. The stable intermediate states from domain nucleation grant excellent memristive plasticity, which allows the spintronic device to be used as an artificial sigmoidal neuron. A proof‐of‐concept live training is performed to recognize written digits, with a high recognition rate comparable to simulation.
Objective The study goal was to determine the diagnostic accuracy of a specific cytokine pattern including interferon-gamma (IFN-γ), interleukin (IL)-10, and IL-6 for hemophagocytic ...lymphohistiocytosis (HLH) in febrile children. Study design In this prospective study, 756 patients with fever admitted to a hematology-oncology unit were enrolled. The causes of fever were documented and the serum cytokines, including IFN-γ, tumor necrosis factor-alpha (TNF-α), IL-10, IL-6, IL-4, and IL-2, were determined using cytometric bead array techniques. Results Of 1474 episodes of fever that were analyzed, 71 episodes of HLH manifested a specific cytokine pattern of highly increased levels of IFN-γ (median level: 1088.5 pg/mL) and IL-10 (623.5 pg/mL) but a moderately increased level of IL-6 (51.1 pg/mL). IL-6 was predominantly increased to varied extents in patients in the sepsis group (244.6 pg/mL) and the nonsepsis infection group (34.7 pg/mL). The diagnostic accuracy of IFN-γ and IL-10 for HLH was 99.5% and 92.8%, respectively. By applying the cutoff point of 100 pg/mL, IFN-γ had a sensitivity of 94.4% and a specificity of 97.2% for HLH. When using the criteria of IFN-γ >75 pg/mL and IL-10 >60 pg/mL, the specificity reached 98.9% and the sensitivity was 93.0%. Conclusions The specific cytokine pattern of markedly elevated levels of IFN-γ and IL-10 with only modestly elevated IL-6 levels has high diagnostic accuracy for HLH and may be a useful approach to differentiate HLH from infection.
Emissions from electronic cigarettes (ECs) may contribute to both indoor and outdoor air pollution and the number of users is increasing rapidly. ECs operate based on the evaporation of e-liquid by a ...high-temperature heating coil. Both puff topography and design parameters can affect this evaporation process. In this study, both mainstream aerosols and heating coil temperature were measured concurrently to study the effects of design parameters and puff topography. The heating coil temperatures and mainstream aerosols varied over a wide range across different brands and within same brand. The peak heating coil temperature and the count median diameter (CMD) of EC aerosols increased with a longer puff duration and a lower puff flow rate. The particle number concentration was positively associated with the puff duration and puff flow rate. These results provide a better understanding of how EC emissions are affected by design parameters and puff topography and emphasize the urgent need to better regulate EC products.
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•A wide range of heating coil temperature and aerosol concentration is observed.•Heating coil temperature increases with longer puff and lower puff flow rate.•Particle number concentration increases with longer puff and higher flow rate.•Mainstream aerosol CMD increases with longer puff and lower puff flow rate.
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