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In this study, the round jet flow behavior arose by the confinement was investigated experimentally and numerically. The confinement characteristics based on multi-scale characterizations in the atmospheric gas jet flow, which generated from a circular symmetrical subsonic nozzle and flowed into a confined round pipe, was used to studied. The studied region near the nozzle possess really short axial length (within 12d), providing initial conditions and boundaries that affected the flow behaviors in this region. A wide range of inlet velocities (0.98 m/s~84.72 m/s) and confined space sizes (1~20) were involved for simulated and quantitative discussions. The velocity profile evolution was recorded by simulations and characterized by a laser Doppler anemometer (LDA) with a resolution of 0.01 m/s. The confinement characteristics were systematically presented to elucidate the performance under the studied confined conditions with different metrics, such as centerline velocity decay (VR), entrainment rate (MR), pressure coefficient (Cp) and length of recirculation region (LR). The results indicated that the recirculation fluid action mainly contributed to the promoted initial velocity profile evolution with the introduction of the confined space. Theoretically, the confined space could reduce the maximum absolute entrainment mass flux, initiating a peak at the center of the recirculation region, which was controlled by the inlet velocity and the confined space size collectively. The remarkable effect of confined space size further contributes to the confinement characteristics of gas jet flow, representing a shortened flow distance despite similar process as that by reducing the diameter ratio (dR). In some cases, because of the miniaturization of confined space size, the dispersion of initial velocity profile evolution was not significant displayed throughout the variable inlet velocity range, especially when the dR was less than 2. This study gives a new insight in the performance of jet flow confined in round pipe, and such knowledge will be helpful to provide great potential and reference to applied fluid mechanics. [ABSTRACT FROM AUTHOR]

Contents This study utilized three staining assays (Annexin V, mitochondrial membrane potential ( JC-1) and TUNEL) for flow cytometric analysis of apoptosis in sex-sorted sperm from four different bulls (A, B, C and D). Correlations between sperm quality and IVF efficiency were then assessed to determine which assay provided the best prediction of IVF efficiency. The results of the Annexin V assays, as well as measures of viable sperm, early apoptosis, necrotic sperm and mitochondrial membrane potential (∆ ψm) showed that the sex-sorted sperm collected from bull A significantly differed from those of the other three bulls (p < 0.05). In addition, the levels of DNA fragmentation in sex-sorted sperm from bull A were significantly lower than those from bulls B and C (p < 0.05). The percentage of cells reaching the cleavage and blastocyst stages in sex-sorted sperm from bull A were significantly greater than those from the other bulls (p < 0.05). A significant positive correlation was observed between viable sperm and the percentage of cells at the cleavage or blastocyst stages (p < 0.05). In contrast, a negative correlation was found between early apoptotic sperm and the percentage of cells at the cleavage or blastocyst stages (p < 0.05). In conclusion, these results indicated that the Annexin V assay was the most reliable technique for the prediction of the IVF success of sex-sorted bovine sperm. [ABSTRACT FROM AUTHOR]

In this paper, ductile β-Ti was selected to toughen brittle high damping intermetallic compound Ti3Sn. An in situ Ti3Sn/β-Ti composite with a composition of Ti77Mo3Sn20 was prepared by arc melting. The composite simultaneously exhibited high yield strength (500 MPa), large plasticity (35%) and high damping capacity (tan δ>0·06). In situ synchrotron high energy X-ray diffraction compression testing revealed that the β-Ti mainly accounts for the plasticity, while Ti3Sn provided the strength of the composite. [ABSTRACT FROM AUTHOR]

In the present paper, the isothermal oxidation behavior of alloy HK40 in H2H2O atmosphere in the temperature range 850-950 °C was systematically investigated by means of TGA, XRD, SEM, and EDS. The results demonstrated that the oxidation of alloy HK40 under low oxygen partial pressure obeyed a cubic instead of parabolic rate law. The values of the oxidation rate constant k at 850, 900, and 950 °C were 0.0079, 0.01886 and 0.04031 mg3/(cm6 h) at 850, 900, and 950 °C, respectively. The scales were composed of MnCr2O4 and Cr2O3. MnCr2O4 mainly existed in the form of blades in the outer part of the scale and its amount gradually increased with increasing temperature. In addition, there were silica particles along the scale/metal interface and indications were found that they contribute to the improvement of scale spallation resistance at high temperature as found by scratch tests. [ABSTRACT FROM AUTHOR]

A new kind of biomedical shape memory TiNiAg alloy with antibacterial function was successfully developed in the present study by the introduction of pure Ag precipitates into the TiNi matrix phase. The microstructure, mechanical property, corrosion resistance, ion release behavior in simulated body fluid, cytotoxicity and antibacterial properties were systematically investigated. The typical microstructural feature of TiNiAg alloy at room temperature was tiny pure Ag particles (at submicrometer or micrometer scales with irregular shape) randomly distributed in the TiNi matrix phase. The presence of Ag precipitates was found to result in a slightly higher tensile strength and larger elongation of TiNiAg alloy in comparison with that of TiNi binary alloy. Furthermore, a maximum shape recovery strain of ∼6.4% was obtained with a total prestrain of 7% in the TiNiAg alloy. In electrochemical and immersion tests, TiNiAg alloy presented good corrosion resistance in simulated body fluid, comparable with that of CP Ti and TiNi alloy. The cytotoxicity evaluation revealed that TiNiAg alloy extract induced slight toxicity to cells, but the viability of experimental cells was similar to or higher than that of TiNi alloy extract. In vitro bacterial adhesion study indicated a significantly reduced number of bacteria (S. aureus, S. epidermidis and P. gingivalis) on the TiNiAg alloy plate surface when compared with that on TiNi alloy plate surface, and the corresponding antibacterial mechanism for the TiNiAg alloy is discussed., (Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

100 patients with W-P-W syndrome who had repeated attacks of supraventricular tachycardia (200-300 beats per minute) associated with syncope and hypotension were treated surgically. Most of them were refractory to medical treatment. Electrophysiological studies were done before operation and the anomalous conduction pathways (ACPs) were confirmed and localized by epicardial mapping during the operation. Among the 100 patients, 44 were of type B, 29 type A and 27 type A + B. The right ACPs were excised and the left ACPs were injected with alcohol. Four patients died after operation. 96 patients were followed up for an average of 24 months; 38 (90.5%) of 42 type B patients, 23 (82.1%) of 28 type A patients, and 17 (65.4%) of 26 type A + B patients were cured.