Glass barrel

FIGURE 4.14 The three styles of buret stopcocks. Left, all Teflon center, Teflon stopcock and glass barrel right, all glass. 

Figure 6.30 Photographs of the conventional melting of a commercial PP resin in an experimental extruder with a glass barrel. In both photographs a melt pool forms near the pushing side of the channel. The screw was rotated at 15 rpm and the barrel temperature was 90 °C. The ruler Is In Inches...

Figure 2-13 Hamilton syringe with a volume of 1 jjlL and divisions of 0.02 xL on the glass barrel. [Courtesy Hamilton Co., Reno, NV.]...

As mentioned earlier, the melting mechanism in screw extruders was first formulated by Tadmor (29) on the basis of the previously described visual observations pioneered by Bruce Maddock. The channel cross section and that of the solid bed are assumed to be rectangular, as in Fig. 9.26. The prediction of the solid bed width profile (SBP), that is the width of the solid bed X as a function of down-channel distance z, is the primary objective of the model, which can be experimentally verified by direct observation via the cooling experiment of the kind shown in Figs. 9.20-9.25. As shown by Zhu and Chen (40), the solid bed can also be measured dynamically during operation by equipping the extruder with a glass barrel. 

Fig. 3.22 The rotary valve operates by rotating a plastic cap. The rotational motion of the cap is translated into linear motion on the Teflon shaft. When the shaft is inserted all the way into the glass barrel, the tip of the shaft pushes against a buildup of glass and stops fluid motion. The O-rings on the shaft prevent leaks past the cap.

There are many designs of rotary valves Some have externally threaded glass barrels, others have internally threaded barrels some have exposed O-rings, others have covered O-rings, and some have no replaceable O-rings. Regardless, they all work with the same operational technique. Rotating cap motion translates into vertical motion on a central shaft, which rides up and down to open or close a pathway. 

If you wish to carry out reactions under dry and/or inert conditions as a matter of routine, the double manifold is perhaps the single most useful item of equipment that will enable you to do this. We recommend that this be a standard item of equipment, permanently fitted to every individual bench and connected to the laboratory inert gas supply by PVC (Tygon) tubing. The manifold consists of two glass barrels, one evacuated and one filled with an inert gas. An outlet is supplied by either barrel of the manifold via a two-way double oblique tap (see Figs. 4.4 and 4.5). Thus, at the turn of the tap, equipment connected to the manifold can be alternately evacuated or filled with inert gas. 

Great care must be exercised at all times to avoid heating the ground-glass barrel of a stopcock. Ground surfaces on soda glass will not survive heating in an air-coal-gas flame. 

FIGURE 14 Alexander being lowered from a ship in a glass barrel to view the wonders of the sea. From The Old French Prose Alexander Romance manuscript, Rouen, 1445. (Roy 15E.V1 f.20v min, by permission of the British Library)... 

The most common method of introducing liquid samples into a gas chromatographic inlet is by means of a microsyringe. Typically, this consists of a calibrated glass barrel... 

Carbon fiber microcylinder electrodes (7 pm in diameter and 400 pm in length) were implanted vertically into the brains of anesthetized rats and were used to monitor electrically evoked dopamine release, as described in detail in the next section. After the electrodes were removed from the animal, the brain tissue was collected and thinly sliced in the plane perpendicular to the axis of the electrodes. When we examined the tissue sections through which the carbon fiber passed, we could find no evidence of the electrode track with the light microscope. This shows that the tissue damage caused by the fiber itself is minimal. On the other hand, tracks could be found in tissue sections through which the glass barrel of the electrode had passed because the barrels were tapered and their... 

The Pasteur pipet comprises a glass barrel, drawn out at one end to form a tip through which liquid is pulled with the aid of a latex suction bulb (Fig. 2.8). These pipets are commonly available in two lengths. Liquid is drawn into the pipet by first compressing the bulb and then inserting the tip of the pipet into the liquid to be transferred. To maximize the efficiency of the transfer, it is best not to compress the bulb more than is needed to draw the desired amoimt of liquid into the tip and barrel of the pipet. With practice, you will learn how much to compress the bulb to pull up a given volume of liquid. 

The cartridge body usually is a syringe-like barrel made of serological-grade polypropylene. Some manufacturers may also offer glass barrels. The barrel normally terminates in a male luer tip for ease of use. Different sizes of barrels are available to accommodate the various amounts of stationary phase used in SPE cartridges. 

Stainless steel plunger travels inside glass barrel actuated by stepper motor... 

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