The extracorporeal shock wave lithotriptor (ECSWL) is a machine that generates shock waves that transfer energy through biologic materials. This study focused the wave at a composite bone-cement (polymethylmethacrylate) interface and evaluated the effects both quantitatively and qualitatively. Six matched sets of dog femora were selected. The intramedullary canals were packed uniformly with cement. One of the set was randomly selected for treatment with impulses while the other served as the control. The bone was then sectioned transversely into discs, and scanning electron microscopy and mechanical push-out studies were performed. The results indicated that the ECSWL does have a loosening effect on the bone-cement interface. Using a paired Student's t-test, the shear strength was significantly less in the treated group than in the control (p < 0.003).Microscopically, the treated specimens revealed relative sparing of the surrounding bone. At the bone-cement interface, however, microfractures, loose bodies, and widening were seen. Revision total arthroplasty has a significant morbidity, which can be partially attributed to cement extraction. The results of this study indicate that the ECSWL may be a useful adjunct in revision surgery by facilitating the extraction of polymethylmethacrylate and thereby reducing the morbidity.Cemented total arthroplasty is a procedure that has been performed for over two de-
Evacuated Tube Transport Technologies (ET3) offers the potential for more than an order of magnitude improvement in transportation efficiency, speed, cost, and effectiveness. An ET3 network may be optimized to sustainably displace most global transportation by car, ship, truck, train, and jet aircraft. To do this, ET3 standards should adhere to certain key principals: maximum value through efficiency, reliability, and simplicity; equal consideration for passenger and cargo loads; optimum size; high speed/high frequency operation; demand oriented; random accessibility; scalability; high granularity; automated control; full speed passive switching; open standards of implementation; and maximum use of existing capacities, materials, and processes.
Evacuated tube transportation (ETT) will be one of the ultra-large-scale vacuum application areas. This paper lists some key vacuum technology issues in ETT: (1) how to construct ultra-large-scale vacuum chamber with lower cost and high reliability, (2) how to evacuate gas out of the ETT tube in short time, (3) how to release heat or reduce temperature in the vacuum tube, (4) how to avoid vacuum discharge, (5) how to make vehicles with airproof shells and life support system, and (6) how to detect leaks and find leak positions efficiently. At the same time, some solutions are proposed.
Evacuated Tube Transportation (ETT) will be the fastest traffic mode on earth in the future, possible over 6000km/h, and low energy consumption, no air pollution, no noise and relatively safe. Different from pipelines for transporting oil, gas and water, the tube of ETT will bear the maglev vehicles running in it, and it should be with reliable airproof ability for keeping required vacuum in the tube. It’s significant to seriously select the proper materials for creating tube wall and design reasonable tube wall structure. In this paper two materials to be used most possibly, steel and concrete, are considered. In addition, some types of tube wall structure are analyzed. This paper also compares the differences on the manufacture, process and construction of ETT tube between the pure steel tube and concrete composite tube. At last, some conclusions are given, some suggestions are put up, and some issues that need to be further analyzed and studied are listed.
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