Traction Devices

Specialized locking stylets are here reported. Other traction devices include snares, sutures, and grasping or other tools used to engage or entrap and remove the lead or lead fragments. 

Locking stylets lock inside the inner lumen of the lead with different locking mechanisms, and recently introduced devices can be unlocked and repositioned if necessary. Even though different kinds of locking stylets have been used in the past, there are only a few types now in use  

Wilkoff locking stylet (Cook Vascular Inc., Leechburg, PA, USA) (Fig. 4.3) this stylet has a small flange at the tip that is locked into the conductor coil when a thin, preloaded cylinder 

3 Wilkoff Locking Stylet after the stylet is advanced to the tip of the lead, unlatch the tubular handle of the locking mechanism by removing the pin (a) and lock the stylet in the lead by firmly advancing the tubular handle forward while holding the loop handle in place (b) 

Liberator (Cook Vascular) (Fig. 4.4) this stylet has a wound spring at the distal portion that is compressed and locked into the conductor coil when a thin, preloaded cylinder is advanced. Therefore, the mechanism is activated by advancement of the cylinder, which causes the wound spring portion to lock in place. This type of locking stylet is universal one size fits all leads with lumen diameter of 0.016 to 0.032 

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At first glance dead-weight tangential traction devices of the type depicted in Fig. 7-1 la appear to be well suited for the determination of the coefficient of static friction, the assumption being that the slider assembly is put in motion when the force exerted on it just exceeds the force of static friction. But experiments by Burwell and Rabinowicz [10]... 

Fig. 4. 14 Other traction devices Bulldog lead extender (a) Soft-Grip hemostat (b) coil expander (c) lead clippers (d) pin vise (e)...

The use of a locking stylet during transvenous removal can be due to the decision to use a traction device (as the main extraction tool or in combination with sheaths). Obviously, if the stylet cannot be inserted or if it stops very early in the coil lumen, traction cannot be performed. Regardless of the use of traction devices, the presence of a stylet into the lead is helpful during any dilatation technique. Either mechanical or powered sheaths, while advancing over the lead and freeing it from binding sites, induce mechanical stress on the lead body. The stiffer the lead, the more effective and safe is dilatation. 

Heavy Duty Traction Device for Working on Packed Snow and Ice. 

Treatments used for various types of fractures are cast immobilization, traction, and internal fixation. A plaster or fiber glass cast is the most commonly used device for fracture treatment. Most broken bones heal successfiiUy once properly repositioned, ie, fixed in place via a cast. This type of cast or brace is known as an orthosis. It allows limited or controlled movement of nearby joints. This treatment is desirable for certain fractures. 

Most induction ac motors are fixed-speed. However, a large number of motor applications would benefit if the motor speed could be adjusted to match process requirements. Motor speed controls are the devices which, when properly applied, can tap most of the potential energy savings in motor systems. Motor speed controls are particularly attractive in applications where there is variable fluid flow. In many centrifugal pump, fan, and compressor applications mechanical power grows roughly with the cube of the fluid flow. To move 80 percent of the nominal flow only half of the power is required. Centrifugal loads are therefore excellent candidates for motor speed control. Other loads that may benefit from the use of motor speed controls include conveyers, traction drives, winders, machine tools and robotics. 

Immobility (due to pain, traction, or use of non-portable medical devices)... 

On the other hand, since most of these reactions are thermally activated, their kinetics are accelerated by the rise in temperature in an Arrhenius-like manner. Therefore, within a much shorter time scale, the adverse effect of these reactions could become rather significant during the storage or operation of the cells at elevated temperatures. In this sense, the long-term and the thermal stability of electrolytes can actually be considered as two independent issues that are closely intertwined. The study of temperature effects on electrolyte stability is made necessary by the concerns over the aging of electrolytes in lithium-based devices, which in practical applications are expected to tolerate certain high-temperature environments. The ability of an electrolyte to remain operative at elevated temperatures is especially important for applications that are military/space-related or traction-related (e.g., electric or hybrid electric vehicles). On the other hand, elevated tem-... 

We now consider some models of polymer structure and ascertain their usefulness as representative volume elements. The Takayanagi48) series and parallel models are widely used as descriptive devices for viscoelastic behaviour but it is not correct to use them as RVE s for the following reasons. First, they assume homogeneous stress and displacement throughout each phase. Second, they are one-dimensional only, which means that the modulus derived from them depends upon the directions of the surface tractions. If we want to make up models such as the Takayanagi ones in three dimensions then we shall have a composite brick wall with two or more elements in each of which the stress is non-uniform. 

The characteristic feature of all Amplatzer devices is the nitinol wire mesh. There are two possible methods of implantation. Either the device is placed entirely into the appendage or the distal disc is expanded in the neck and the proximal disc in the left atrium. The risk of residual shunting around the device is increased when it is totally inserted into the LAA with no part protruding into the atrium. The Amplatzer occluder series holds the widest spectrum of device sizes (4 to 40 mm), The device is attached to a delivery cable and can simply be opened or recollapsed into the delivery catheter. Release is by unscrewing the device after first testing stability with simple traction. 

Varakin I, Klementov A, Litvinenko S, Starodubtsev N, Stepanov A. Application of ultracapacitors as traction energy sources. Proceedings of the 7th International Seminar on Double Layer Capacitors and Similar Energy Storage Devices, Deerfield Beach, FL, 1997. 

In order to satisfy the stress-free boundary condition, coupled compressional and shear waves propagate together in a SAW such that surface traction forces are zero (i.e., T y = 0, where y is normal to the device surface). The generalized surface acoustic wave, propagating in the z-direction, has a displacement profile u(y) that varies with depth y into the crystal as... 

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