This study reports the reinforcement and fracture toughening mechanism of pristine multi-walled carbon nanotubes (MWCNTs) on epoxy matrix. The tensile strength and fracture energy (G IC ) of the epoxy polymer increased simultaneously upon the addition of a small amount of MWCNTs. The fracture surfaces of single-edgenotch three-point bending test specimens were analysed by scanning electron microscopy, and the double-notch four-point bending technique was used to investigate the fracture process by transmission electron microscopy, respectively. MWCNT pull-out and subsequent plastic void growth were found; meanwhile, fracture of MWCNTs was observed along the crack propagation path. The theoretical model of shearing band initiated by the stress concentrations around the MWCNTs is the dominant toughening mechanism. While the crack bridging of MWCNTs and the plastic void growth of epoxy also have a toughening effect.
Aim?Our hypothesis is that an improvised low-cost peripheral nerve stimulator is equally effective compared with a high-cost muscle stimulator for anorectal malformation surgery.
Methods?A modified Micro Stim (MS) peripheral nerve stimulator was compared with the Pe?a Muscle Stimulator (PS2) on identification of muscle groups during surgery, tissue energy delivery, and cost. A consecutive series of 6 patients (5 boys) with weight 5.9 to 11?kg underwent posterior sagittal anorectoplasty (PSARP). The types of malformations included four prostatic fistulae, one bulbar fistula, and one vestibular fistula. In the course of each operation, both MS and PS2 devices were used to identify muscle groups in a head-to-head comparison with video documentation. The energy delivery was determined using a digital oscilloscope at settings used during the operations (#9 on the MS and 120?mA on the PS2). Price quotes for each device were obtained from commercial vendors.
Results?The subjective assessment of the surgical team was that both devices demonstrated equivalent utility in identifying critical muscle groups, although the MS probe was less convenient to use. There were no intraoperative complications, including tissue burns with either device, and no postoperative complications. The energy delivery of the devices was similar, 23.5 mW and 25.3 mW for the MS and PS2, respectively. The cost of the MS was US$ 162 and the PS2 was US$ 12,371.
Conclusion?The MS nerve stimulator demonstrated equivalent effectiveness compared with the PS2 muscle stimulator at 75-fold lower cost. The MS device may serve as a low-cost effective tool for PSARP.
The restaurant intelligent cleaning robot, belongs to the field of robot technology, including driving the base, control the body and vision system. Mechanical arms are installed on both sides of the top of the machine body. One of the bottom end of the robot arm is installed with clamping claws, and the other mechanical arm bottom is installed with Clean hands for desktop cleaning. Driving wheels are symmetrically arranged on both sides of the bottom surface of the base, the body internal top installed vacuuming assembly, vacuuming components of the vacuum port through the pipe to connect the vacuum cover. Combined with lidar and other sensors, it can achieve automatic identification, automatic cleaning, multi-use, flexible movement. It also can reduce the probability of collision tables and chairs, the use of higher reliability, more convenient.
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