Fire-polish

The Hartford-Empire 28 is a press-and-blow machine used to make articles such as drinking glasses (tumblers). It uses paste molds and the ware is rotated to avoid the mold seams jars with screw threads cannot be produced. The product leaves the machine as an almost closed, hoUow object and is finished by severing and fire-polishing with a bum-off machine. 

The apparatus consists of a 100-ml distilling flask equipped with a dropping funnel and arranged for distillation through an efficient condenser. The condenser is connected to two receiving flasks in series, the second of which contains 20-30 ml of ether. The inlet tube of the second receiver dips below the surface of the ether and both receivers are cooled in ice baths. All connections in the setup are made with bored cork stoppers and all glass tubing is fire polished (Fig. 17.1). 

Salt that sticks to the sides of the Erlenmeyer flask may be loosened with a piece of 10-mm. glass tubing that has not been fire-polished. 

Electrophysiological Experiments. Guinea pig myocardial cells prepared as described previously 24) were superfused at 37 C with a Tyrode solution. Electrical properties of the myocytes were examined by the patch-clamp methods (25) using fire-polished pipettes. The current was measured by means of a patch-clamp amplifier, stored on the tape through a digital PCM data recording system, and analyzed with a computer. 

The end of the jacket is rounded off so that when the cup is inserted the jet will be just inside the cup. The cup is next sealed in with an internal seal. The larger tube is then rounded off at C (Figure 53, V), and a side arm is put on at the bottom and bent round. Lastly, the two side arms are cut off and fire-polished to give the final pump seen in Figure 53, V. 

To fix on the window as shown in Figure 75,7, a bulb is blown in the capillary, the top of the bulb is blown out to a bubble, knocked off, and the end remaining is fire-polished and finally ground flat. The tube can be filled with gas through a side arm joined to one of the electrode chambers the spectrum tube may be sealed off, or provided with a stopcock. TIk capillary tube in Figure 75, II, is sealed to the glass at one end only of the capillary. To do this, the capillary is joined to a wider tube, which is cut off and flared out to make the... 

Evaporation of an ethereal solution of hydrogen peroxide gave a residue of which a drop on a platinum spatula exploded weakly on exposure to flame. When the sample (1-2 g) was stirred with a glass rod (not fire polished), an extremely violent detonation occurred. 

The checkers added the slurry via a large, medium-bore, glass funnel with fire-polished edges. In one of three runs a small, sharp report was heard, apparently from a source above the liquid in the beaker the yield of biphenylene in this run did not differ significantly from that obtained in the other runs. 

Pull and fire polish patch pipettes when filled with buffer solution show a resistance of 3-5 MQ and a series resistance of 5-6 MQ. 

Isolate or cultivate cells according to the protocols given before. Pull pipettes of 2-3 resistance, fire-polish in a microforge or treat with sylgard. Prepare the following solutions. 

PORCELAIN ENAMEL. A substantially vitreous inorganic coating bonded to metal by fusion above 426 C (ASTM), Composed of various blends of low-sodium frit, clay, feldspar, and other silicates ground in a ball mill and sprayed onto a metal surface (steel, iron, or aluminum), to which it bonds firmly after firing, giving a glasslike fire-polished surface. 

Fig. 1.12. Assembly of a filter cannula or Green filter. (a) A piece of glass capillary tubing, which has been blown open and fire-polished to form a lip on one end, is attached to the cannula with epoxy cement, (b) Filter paper is folded over the glass capillary and secured with wire.

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