Bulbs

Replacing a light bulb is a simple task, but it should be noted that the new bulb must not be of higher wattage. When replacing fluorescent tubes, special care must be used, since serious injury could result from breakage. It is not advisable to mix tubes of different colors when replacement becomes necessary. 

---

Beckmann thermometer A very sensitive mercury thermometer with a small temperature range which can be changed by transferring mercury between the capillary and a bulb reservoir. Used for accurate temperature measurements in the determination of molecular weights by freezing point depression or boiling point elevation. 

Used (particularly He, Ar) to provide an inert atmosphere, e.g. for welding, and in electric light bulbs, valves and discharge tubes (particularly Ne). Liquid He is used in cryoscopy. The amounts of He and Ar formed in minerals by radioactive decay can be used to determine the age of the specimen. Xe and to a lesser extent Kr and Rn have a chemistry the other noble gases do not form chemical compounds. 

Another application areas of microtomography are biology and agriculture. Fig.4a shows an X-ray transmission image through the tulip bulb in wet conditions. Damaged area can be found in the surface of this bulb. Fig.4b shows the reconstructed cross section with information about depth of damaged volume. 

Fig.4.Microtomography of tulip bulb shadow image (a) and cross-sections (b)...

MP-suspension by automated ASTM-bulb Magnetization current by Hall-Sensor Magnetization time UV-Light intensity All Liquids (fluorescence, contamination) Process times and temperatures Function of spraying nozzles, Level of tanks Flow rates (e.g. washing, water recycling) UV-Light intensity... 

The condition of the magnetic particle suspension is controlled by an automated ASTM-bulb. The bulb is connected to the currently used Magentic particle suspension tank by a bypass, so the suspension in use is flowing through the bulb too. In user defined periods a valve is closed and the Magentic particle suspension remained into the bulb is analysed. The automatic bulb has the ability to measure the extinction and transmission of the suspension related to the time (Figure 1, Figure 2)... 

Figure 1 Operating Principles of an Automated ASTM-Bulb...

Kraijnovitch D J, Parmenter C S and Catlett D L Jr 1987 State-to-state vibrational transfer in atom-molecule collisions. Beams vs. bulbs Chem. Rev. 87 237-88... 

Optical metiiods, in both bulb and beam expermrents, have been employed to detemiine tlie relative populations of individual internal quantum states of products of chemical reactions. Most connnonly, such methods employ a transition to an excited electronic, rather than vibrational, level of tlie molecule. Molecular electronic transitions occur in the visible and ultraviolet, and detection of emission in these spectral regions can be accomplished much more sensitively than in the infrared, where vibrational transitions occur. In addition to their use in the study of collisional reaction dynamics, laser spectroscopic methods have been widely applied for the measurement of temperature and species concentrations in many different kinds of reaction media, including combustion media [31] and atmospheric chemistry [32]. 

Corrected Melting-points. In all the above determinations of melting-points, the values obtained are described as uncorrected, since no allowance has been made for the fact that the column of mercury in the thermometer is at a lower temperature than that in the bulb. For most purposes it is sufficient to record this uncorrected value, which is usually only slightly lower than the corrected value. 

The thermometer should be so arranged that the top of the bulb is just level with the centre of the side-arm of the distilling-flask. 

The water-condenser B shown in Fig. 2 represents the simplest and cheapest kind, which because of its limited efficiency should be at least 2 feet long. Fig. 3(A) IV shows a bulb condenser, which, although also cheap, is much more efficient. In Fig. 

The distillation heads Fig. 22(F) and Fig. 22(G) can be fitted with thermometers having a ground-glass cone just above the bulb (Fig. 22(M)). These are expensive, and it is usually more convenient to fit a thermometer pocket (Fig. 22(N)) which consists of a small well , fitting as shown into the neck of the flask. A small volume of mercury is placed in the well just to cover the bulb of a conventional thermometer, and thus provides excellent thermal contact between the thermometer and the sides of the pocket. 

All thermometers for semi-micro preparations must have very small bulbs. They may often be inserted into flasks through a short collar of rubber tubing in place of the customary corks. 

In order to save the cost of the distilling-flask (which after the above treatment is useless for further work), the mixture may be distilled from a small retort made by blowing a suitable bulb on the end of a rather thick-walled tube of about 8-10 mm. internal diameter the tube is then bent through almost 90° a few cm. above the bulb, cut to a suitable length, and the Open end fitted into the boiling ube as before. 

Fit a three necked 250 ml. flask with a central rubber-sleeved or mercury-sealed stirrer, c/. Fig. 23(c), p. 45, where only two necks are shown, and with a thermometer the bulb of which reaches as near the bottom of the flask as the stirrer allows the third neck will carry at first a dropping-funnel and later a reflux condenser. Place 20 g. (19-5 ml.) of ethyl acetoacetate and 45 ml. of glacial acetic acid in the flask and by ice-water cooling adjust the temperature of the stirred mixture to 5 -7° maintain this temperature whilst adding a solution of 5 4 g. of sodium nitrite in 8 ml. of water slowly from the dropping-funnel during 15 minutes. Continue the stirring for 20-30 minutes, and then... 

The reaction is carried out in a 2-litre long-necked round-bottomed flask, to which is fitted an efficient reflux water-condenser, capable of condensing a sudden rush of vapour without choking. For this purpose, a long bulb-condenser, similar to that shown in Fig. 3(A) (p. 9) is best, but the inner tube must be of wide bore (at least 12 mm.). Alternatively, an air-condenser of wide bore may be used, an.d a short double-surface water-condenser fitted to its top. A steam-distillation fitting for the flask should also be prepared in advance, so that the crude product can subsequently be steam-distilled directly from the flask. The glj cerol used in the preparation must be anhydrous, and should therefore be dehydrated by the method described on p. 113. 

The furnace (Fig. 74) consists primarily of an iron box A, having 3 or 4 tubes (e.g., B) arranged in a horizontal row, and dipping slightly from the open (left-hand) to the closed (right-hand) end. The top, which usually forms a loose lid to the rest of A, carries a thermometer T, and care should be taken to ensure that the bulb of the thermometer is not touching any part of the metal box. The Carius tube encased in... 

The apparatus consists of a tube T (Fig. 76) usually of total height about 75 cm. the upper portion of the tube has an internal diameter of about I cm., whilst the lower portion is blown out as shown into a bulb of about 100 ml. capacity. Near the top of T is the delivery-tube D of coarse-bored capillary, bent as shown. The tube T is suspended in an outer glass jacket J which contains the heating liquid this jacket is fitted around T by a split cork F which has a vertical groove cut or filed m the side to allow the subsequent expansion of the air in J. The open end of the side-arm D can be placed in a trough W containing water, end a tube C, calibrated in ml. from the top downwards, can be secured ts shown over the open end of D. 

For this purpose the thermometer has a reserve supply of mercury in the reservoir R. For working at low temperatures, more mercury is required in the bulb, and an extra supply is brought down from R for working at higher temperatures, less mercury is required in the bulb to enable readings to be made on the scale S, and therefore a suitable quantity of mercury is detached from that in the bulb and deposited in the reservoir. 

If, on the other hand, the thermometer has previously been used at some temperature below the freezing-point of benzene, when the bulb is originally placed in the beaker of water at 7-8 C., the mercury will rise in the capillary and ultimately collect in the upper part of the reservoir at a. When the expansion is complete, again tap the thermometer sharply at R so that this excess of mercury drops down into b, and then as before check the success of the setting by placing the thermometer m some partly frozen benzene. In either case, if the adjustment is not complete, repeat the operations, making a further small adjustment, until a satisfactory result is obtained. 

---