A mathematical model of critical jet heights causing droplets splashing in BOF steelmaking

It is important to understand the physical interaction between top-blown oxygen jet and liquid bath in basic oxygen steelmaking furnaces (BOF). In this study, cold model experiments were carried out to investigate the cavity depth, diameter and the instability at the gas-liquid interface. Images of the cavities were captured by a high-speed video camera to study cavity performances. A modified judging equation of the gas-liquid interface instability was developed by the critical jet flow and the critical jet height at a determined jet diameter. The critical parameters were in good agreement with experimental measurements

A mathematical model of critical jet heights causing droplets splashing in BOF steelmaking

It is important to understand the physical interaction between top-blown oxygen jet and liquid bath in basic oxygen steelmaking furnaces (BOF). In this study, cold model experiments were carried out to investigate the cavity depth, diameter and the instability at the gas-liquid interface. Images of the cavities were captured by a high-speed video camera to study cavity performances. A modified judging equation of the gas-liquid interface instability was developed by the critical jet flow and the critical jet height at a determined jet diameter. The critical parameters were in good agreement with experimental measurements

Enhanced energy storage density by inducing defect dipoles in lead free relaxor ferroelectric BaTiO3-based ceramics

In this work, Mn-doped 0.9BaTiO3-0.1Bi(Mg2/3Nb1/3)O3 ceramics were prepared by the conventional solid state reaction method, and the effect of defect dipoles on energy storage properties of lead free relaxor ferroelectric BaTiO3-based ceramics was studied. The crystal structure, dielectric properties, and energy storage properties were explored in detail. It was found that polarization hysteresis (P-E) loops of 0.9BaTiO3-0.1Bi(Mg2/3Nb1/3)O3-x wt. % MnCO3 (0.2–0.5) ceramics took on high maximum polarization (Pmax) and low remanent polarization (Pr). Meanwhile, recoverable energy density (Wrec) and energy conversion efficiency (η) were obviously enhanced by inducing defect dipoles into BaTiO3-Bi(Mg2/3Nb1/3)O3 relaxor ferroelectrics. The 0.9BaTiO3-0.1Bi(Mg2/3Nb1/3)O3-0.3 wt. % MnCO3 ceramic was found to exhibit good energy storage properties with a Wrec of about 1.70 J/cm3 and a η ∼ 90% under an electric field of 210 kV/cm. The breakdown electric field and Wrec of BaTiO3-based materials were significantly increased in the present work, and they might be good candidates for high power energy storage applications

A Novel Composite Hydrogen Sensor Based on Pd Nanoclusters/TiO\u3csub\u3e2\u3c/sub\u3e Nanotube Arrays

A novel composite hydrogen sensor, consisting of Pd nanoclusters/TiO2 nanotube arrays, was fabricated and evaluated at room temperature. The Pd nanoclusters layer was deposited on top surface of the nanotube arrays by using a direct current (DC) magnetron sputtering method. Resistive response of the composite sensors to 0.5% hydrogen was measured. Experimental results indicated that the Pd nanoclusters can quickly and continually form or break multiple passages by absorbing or desorbing hydrogen, so that the composite hydrogen sensors have promising hydrogen sensitivity at room temperature

Sacrificial layer-assisted nanoscale transfer printing

Transfer printing is an emerging assembly technique for flexible and stretchable electronics. Although a variety of transfer printing methods have been developed, transferring patterns with nanometer resolution remains challenging. We report a sacrificial layer-assisted nanoscale transfer printing method. A sacrificial layer is deposited on a donor substrate, and ink is prepared on and transferred with the sacrificial layer. Introducing the sacrificial layer into the transfer printing process eliminates the effect of the contact area on the energy release rate (ERR) and ensures that the ERR for the stamp/ink-sacrificial layer interface is greater than that for the sacrificial layer/donor interface even at a slow peel speed (5 mm s(−1)). Hence, large-area nanoscale patterns can be successfully transferred with a yield of 100%, such as Au nanoline arrays (100 nm thick, 4 mm long and 47 nm wide) fabricated by photolithography techniques and PZT nanowires (10 mm long and 63 nm wide) fabricated by electrohydrodynamic jet printing, using only a blank stamp and without the assistance of any interfacial chemistries. Moreover, the presence of the sacrificial layer also enables the ink to move close to the mechanical neutral plane of the multilayer peel-off sheet, remarkably decreasing the bending stress and obviating cracks or fractures in the ink during transfer printing

Discrete Razumikhin-type technique and stability of the Euler-Maruyama method to stochastic functional differential equations

A discrete stochastic Razumikhin-type theorem is established to investigate whether the Euler--Maruyama (EM) scheme can reproduce the moment exponential stability of exact solutions of stochastic functional differential equations (SFDEs). In addition, the Chebyshev inequality and the Borel-Cantelli lemma are applied to show the almost sure stability of the EM approximate solutions of SFDEs. To show our idea clearly, these results are used to discuss stability of numerical solutions of two classes of special SFDEs, including stochastic delay differential equations (SDDEs) with variable delay and stochastically perturbed equations

The three dimensional microstructural network of elastin, collagen and cells in Achilles tendons

Similar to most biological tissues, the biomechanical and functional characteristics of the Achilles tendon are closely related to its composition and microstructure. It is commonly reported that type I collagen is the predominant component of tendons and is mainly responsible for the tissue's function. Although elastin has been found in varying proportions in other connective tissues, previous studies report that tendons contain very small quantities of elastin. However, the morphology of and the microstructural relationship among the elastic fibres, collagen and cells in tendon tissue have not been well examined. We hypothesize the elastic fibres, as another fibrillar component in the extracellular matrix, have a unique role in mechanical functions and microstructural arrangement in Achilles tendons. Using confocal and Second Harmonic Generation (SHG) imaging techniques, this study examined the 3-dimensional microstructure of the collagen, elastin and cells in the mid-portion of hydrated rabbit Achilles tendons. It has been shown that elastic fibres present a close connection with the tenocytes. The close relationship of the three components has been revealed as a distinct, integrated and complex microstructural network. Notably, a "spiral" structure within fibril bundles in Achilles tendons was observed in some samples in specialized regions. This study substantiates the hierarchical system of the spatial microstructure of tendon, including the mapping of collagen, elastin and tenocytes, with 3-dimensional confocal images

BaTiO3–Bi(Li0.5Ta0.5)O3, lead-free ceramics, and multilayers with high energy storage density and efficiency

BaTiO3-based materials show great promise for energy storage capacitors, but their low breakdown strength and high remnant polarization currently result in relatively low energy density. Here, we report a novel (1–x)BaTiO3–xBi(Li0.5Ta0.5)O3 (0.06 ≤ x ≤ 0.12, BT–xBLT) lead-free ceramic with electric field (E) ∼ 280 kV cm–1, discharge energy density (We) ∼ 2.2 J cm–3, charge–discharge efficiency (η) > 89% that is thermally stable up to 160 °C and with a fast discharge time (≤0.5 μs). Multilayers of compositions with x = 0.1 also exhibited high We = 4.05 J cm–3 and η = 95.5%, demonstrating their potential for energy storage

A Note on Exact Solutions and Attractor Mechanism for Non-BPS Black Holes

We obtain two extremal, spherically symmetric, non-BPS black hole solutions to 4D supergravity, one of which carries D2-D6 charges and the other carries D0-D2-D4 charges. For the D2-D6 case, rather than solving the equations of motion directly, we assume the form of the solution and then find that the assumption satisfies the equations of motion and the constraint. Our D2-D6 solution is manifestly dual to the solution presented in 0710.4967. The D0-D2-D4 solution is obtained by performing certain $[SL(2,{\bf Z})]^{3}$ duality transformations on the D0-D4 solution in 0710.4967.Comment: 20 pages, LaTe