Sealed tube

Sublimation. This is a most useful process for small-scale work as the losses are comparatively small. This can be performed (a) In a long narrow tube sealed at one end. The material is shaken to the closed end of the tube, which is then inserted horizontally in a metal-heating block (Fig. 50) (b) In the cold-finger device (Fig. 35, p. 62)-... 

Apparatus. Prepare an open strong-walled glass tube sealed at the lower end, precisely as in Fig. 72 (c) (p. 417), but about 35 cm. in length, and having internal and external diameters 9 and 13 mm. respectively (Fig. 90). 

Fig. 7. Comparison of the thermal stabihty, ie, formation of monomer and loss of of FRPS and APS upon heating for 2.5 h at 285°C in glass tubes sealed at 0.67 or 13.3 kPa. A is FRPS residual styrene formed B, FRPS loss C, APS loss and D, APS residual styrene formed. To convert kPa to...

A mixture of 50 g. (0.26 mole) of anhydrous stannous chloride and 225 ml. of dry ether is placed in a 1-1. three-necked round-bottomed flask fitted with a rubber-tube sealed stirrer, an inlet tube reaching nearly to the bottom of the flask, and a reflux condenser (Note 2) protected by a calcium chloride drying tube. The mixture is saturated with dry hydrogen chloride (Note 3) with continuous stirring. Within 3 hours all the stannous chloride dissolves, forming a clear viscous lower layer. The source of hydrogen chloride is then disconnected, and the freshly prepared imidyl chloride is transferred into the mixture with the aid of 25 ml. of dry ether (Note 4). Stirring is continued for 1 hour, and then the reactants are allowed to stand at room temperature for 12 hours. 

Acrylic tubes may be prepared by adding a calculated amount of syrup to an aluminium tube, sealing both ends, purging the air with nitrogen and then rotating horizontally at a constant rate. The whole assembly is heated and the... 

The fixed-tubesheet exchanger is the most common, and generally has the lowest capital cost per ft of heat-transfer surface area. Fixed-tubesheet exchangers consist of a series of straight tubes sealed between flat, perforated metal tubesheets. 

One form of calomel electrode is shown in Fig. 15.1(a). It consists of a stoppered glass vessel provided with a bent side tube fitted with a three-way tap which carries a short upper and a long lower tube the latter is drawn out to a constriction at the bottom end. A short platinum wire is fused into the bottom of the vessel so that it protrudes into the interior, and a narrow glass tube sealed to the bottom of the vessel is bent round parallel to the vessel. A little mercury placed in the bottom of this tube provides electrical connection with the interior of the vessel through the sealed-in platinum wire. Mercury and mercury compounds must be handled with care (see Section 16.8). 

This equation shows that the pressure, P, exerted by a column of mercury is proportional to the height of the column. Mercury inside a tube sealed at one end and inverted in a pool of mercury will fall until the pressure exerted by the mercury balances the atmospheric pressure. Therefore, the height of the column can be used as a measure of atmospheric pressure. 

ESCA Sample Pretreatment. Samples were pelleted and cut to fit into a rectangular depression in an ESCA sample probe similar in design to one used by Hercules (16). The portion of the probe holding the catalyst sample could be withdrawn into an outer cylinder and sealed under an atmosphere of the pretreatment gas. For pretreatment the calcined samples were exposed to a hydrogen flow at one atmosphere and heated to AOO C. After this pretreatment the sanqile was withdrawn into the insertion tube, sealed in the pretreatment gas, inserted into the ESCA, evacuated, and then the ESCA spectra were recorded. A similar procedure was followed for the uncalcined catalysts except that the temperature was first increased in hydrogen flow to SOO C and held at this temperature for 3 to 4 hours the sample was then heated to 400 C and held at this temperature for 18 hours. 

The experimental procedure employed a capillary viscometer made of quartz as shown in Fig. 26. A solid sample was put in the filtration chamber and the top of the chamber was sealed under a vacuum. Then the sample was heated to melting and filtered into the viscometer and the connecting tube sealed at the middle. The viscometer was settled inside a transparent electric furnace and after the temperature of the melt was stabilized, the furnace containing the viscometer was turned upside down, which transferred the melt into the funnel. Then the tube was turned... 

Reaction rate experiments were conducted in NMR tubes sealed with Teflon valves. In an inert atmospere glovebox, catalysts and internal standard, TMS4C, were weighed into the tube, followed by addition of solvents and reactants. The tube was immediately inserted in the preheated (50 °C) probe of a 500 MHz Varian Unitylnova spectrometer. To acquire spectra the sample was irradiated twice with a 30° pulse, 5 sec acquisition time, and 120 sec delay. 

It reverts violently to anthracene at 73°C in a tube sealed under argon. 

Cable jackets, hose jackets, tubing, seals, automotive bellows, mechanical parts, gear wheels, business machine parts. 

Figure 1.2 A barometer is a device for measuring pressures. A vacuum-filled glass tube (sealed at one end) is placed in a trough of mercury with its open end beneath the surface of the liquid metal. When the tube is erected, the pressure of the external air presses on the surface and forces mercury up the tube. The height of the mercury column li is directly proportional to the external pressure p...

An evacuated hollow tube sealed at one end is filled with mercury, and then the open end is immersed in a pool of mercury. Gravity will tend to pull the liquid level inside the tube down, while the weight of the atmospheric gases on the surface of the mercury pool will tend to force the liquid up into the tube. These two opposing forces will quickly balance each other, and the column of mercury inside the tube will stabilize. The height of the column of mercury above the surface of the mercury pool is called the atmospheric pressure. At sea level the column averages 760 mm high. This pressure is also called 1 atmosphere (atm). Commonly, the unit torr is used for pressure, where 1 torr = 1 mm Hg, so that atmospheric pressure at sea level equals 760 torr. The SI unit of pressure is the pascal (Pa), so that 1 atm = 760 mm Hg = 760 torr = 101,325 Pa (101.325 kPa). In the United States pounds per square inch (psi) is sometimes used, so that 1 atm = 14.69 psi. 

This partial condenser, which is a modificatioh of one described by Hahn,1 is very effective in reducing the time required for fractional distillation of many mixtures. It is best constructed of Pyrex. The dimensions given are approximate and may be varied to suit individual needs. The inside container is a 30 by 140 mm. Pyrex test tube sealed at the top to standard Pyrex tubing. It is very effective in the purification of cyclohexene (Org. Syn. Coll. Vol. 1, 177).2 The crude hydrocarbon mixture is first put into the flask with ethyl alcohol in the partial condenser, and the whole heated as long as a distillate is obtained. The alcohol is then replaced by ethylene chloride and the cyclohexene collected. 

Gd-Pt-Al compounds have been prepared by reacting Gd and Pt in the proper atomic ratio with a 10 fold excess of Al (Lattumer and Kanatzidis 2002). The mixture, placed in a silica tube sealed under vacuum was slowly heated to 1000°C, held at this temperature for several hours and slowly (over a few days) cooled to room temperature. The aluminium flux was removed by soaking the crucible in 5 M NaOH for 1 day. Gdi 33Pt3Al8, Gdo.67Pt2Al5 (and also compounds with Si) have been prepared the main product, however, in all the syntheses was GdAl3. 

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