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Thoracic aortic aneurysm (TAA) is a severe cardiovascular disease with a high mortality rate, if left untreated. Clinical observations show that aneurysm growth can be linked to undesirable hemodynamic conditions of the aortic aneurysm. In order to gain more insight on TAA formation, we developed a computational framework in vitro to investigate and compare the flow patterns between pre-aneurismal and post-aneurismal aorta using a deformable wall model. This numerical framework was validated by an in vitro experiment accounting for the patient-specific geometrical features and the physiological conditions. The complex flow behaviors in the pre-aneurismal and post-aneurismal aorta were evaluated experimentally by particle image velocimetry (P1V). Our experimental results demonstrated flow behaviors similar to those observed in the fluid-structure interaction (FSI) numerical study. We observed a small vortex induced by the non-planarity of pre-aneurismal aorta near the aortic arch in pre-ancurysmal aorta may explain the aneurysm formation at the aortic arch. We found that high endothelial cell action potential (ECAP) correlates with the recirculation regions, which might indicate possible thrombus development. The promising image-based fluid-structure interaction model, accompanied with an in vitro experimental study, has the potential to be used for performing virtual implantation of newly developed stent graft for treatment of TAA. [ABSTRACT FROM AUTHOR]

We hypothesized that, in providing biomechanical strength, at least one of the two middle strands in a modified six-strand Lim-Tsai flexor tendon repair could be divided without obvious reduction in repair strength owing to uneven load bearing. A total of 40 porcine flexor digitorum profundus tendons were repaired using the six-strand Lim-Tsai technique with a 4-0 FiberLoop® suture and then divided into four equal groups. (no cut, one middle strand cut, both middle strand cut, one side strand cut). The biomechanical performance of repaired tendons was tested and found to vary according to the location of the cuts. [ABSTRACT FROM AUTHOR]

This paper presents an online, accurate and easy to use method for metal transfer mode classification using the input electrical impedance of arc welding as the signature. The records of the input electrical impedance are obtained by processing the welding voltage and current signals picked up at the output terminal of a welding machine. Similar to a typical linear electrical circuit consisting of a resistor, an inductor and a capacitor connected in series, the real and imaginary part of the input electrical impedance represents the combination of these electrical elements in the arc welding. Their variations directly reflect the switching among the metal transfer modes. A few experiments were conducted to confirm the above working principle and correlations between the input electrical impedance of arc welding and metal transfer. The results were then used to develop a method for online classification of metal transfer modes. [ABSTRACT FROM AUTHOR]

We reported a new method based on the input electrical impedance of a welding system to measure the resistance of the welding system for the arc power calculation in fusion welding. This impedance can be obtained by dividing the measured voltage to current in their analytic form. Two time recorded waveforms, namely, resistance and reactance of impedance, are therefore calculated. Theoretically, the resistance used for arc power calculation is obtained by dividing measured voltage to current directly without considering the influence of inductance. Through experimental studies, we confirm that the error of arc power calculation incurred by the influence of inductance can range from 2 to 10% depending on the welding voltage and current setting. Since the proposed method can obtain the resistance of the welding system without the influence of inductance, it is a better approach as compared with the current method to obtain the accurate resistance and then arc power. [ABSTRACT FROM AUTHOR]

Integrated sensors in fitness and sports equipment have been developed in the last two decades. A zinc oxide (ZnO) thin film could be a suitable material for such applications due to its excellent physical and piezoelectric properties. In this paper, nanocrystalline ZnO films were deposited on silicon (Si) wafers with different substrate tilt angles (30° to 75°) and sputtering durations (2 to 4 h) using RF magnetron sputtering at room temperature. ZnO thin film topographical properties, film thickness (0.8 to 3.7 Îm) and columnar inclined angle (14° to 34°) on the different locations of specimens were characterised by scanning electron microscope (SEM). Simulation and experimental results from the sensor arrays were also fabricated using fabrication techniques compatible with a standard micromachining process. The simulation and experiments for sensor arrays proved that sensor arrays were capable of distinguishing the differences of contact force values, contact locations and directions. Moreover, ZnO thin film micro-cantilevers were fabricated and tested by an AC impedance technique and a laser doppler vibrometer (LDV). The results exhibited good piezoelectric properties of shear-mode ZnO thin film driven cantilevers. [ABSTRACT FROM AUTHOR]

We hypothesized that, in providing biomechanical strength, at least one of the two middle strands in a modified six-strand Lim-Tsai flexor tendon repair could be divided without obvious reduction in repair strength owing to uneven load bearing. A total of 40 porcine flexor digitorum profundus tendons were repaired using the six-strand Lim-Tsai technique with a 4-0 FiberLoop ® suture and then divided into four equal groups. (no cut, one middle strand cut, both middle strand cut, one side strand cut). The biomechanical performance of repaired tendons was tested and found to vary according to the location of the cuts.