Dosing bulbs

Therefore, in order to meter small quantities of materials in vacuo, the use of glass phials or calibrated break-seals, described in Sections 3.1.2 and 3.1.3. respectively, is recommended. Even smaller quantities of moderately volatile materials can be dosed by means of calibrated vapour-dosing bulbs (see Section 3.1.5). 

Fig. 3.11. Schematic drawing of assembly for dosing water into phials by volume of vapour. A reservoir containing distilled, deaerated water, B dosing bulb of known volume, P breakable phials, C container holding MejSiCl, D thermostat bath.

The minimum concentration of hydrocarbon necessary to obtain explosions by the method of heating with oxygen in dosed bulbs increases rapidly with the molecular weight. Thus, with hexane no explosions occur below 10 per cent hydrocarbon concentration, and with octane the minimum concentration necessary is 33 per cent when a heating rate of 1° C. per minute is used. Diiso-amyl failed to ignite at this rate of heating at any concentration. Lewis observed no distinction between explosion temperature and critical inflexion temperature."... 

Consider two bulbs separated by a valve. Both bulbs are maintained at tiie same temperature. Assume that when the valve between the two bulbs is dosed, the gases are sealed in their respective bulbs. When the valve is dosed, tiie following data apply ... 

Missing from this list is Peter McGahey, my developmental editor, who deserves special thanks. He soothed frayed nerves and lifted sagging spirits with his positive, optimistic personality. His good humor provided an extra dose of energy. It also helped to get off topic once in a while to chat about tulip bulbs in the spring and perennials in the summer Thanks, Peter. You were an oasis of calm on many days. 

Ruckert, R. et al. High-dose proinflammatory cytokines induce apoptosis of hair bulb keratinocytes in vivo. Br. J. Dermatol. 143, 1036, 2000. 

Bronchospasm Hand-bulb Nebulizer 4 inhalations (range 3-7 inhalations) undiluted. Maybe repeated up to 5 times/day. Metered Dose Inhalation 1-2 inhalations q4h. Wait 1 min before administering 2nd inhalation. IPPB, Oxygen Aerosolization 0.5-1 ml of a 0.5% or 0.5 ml of a 1% solution diluted 1 3. 

From intact vegetable crops, apart from tuber, bulb, and root crops, tomatoes and asparagus show potential for radiation treatment. The development of fungal decay in tomatoes caused by Alternaria, Botrytis, or Rhizopus spp. can be controlled using doses of approx. 3 kGy. However, softening and the loss of characteristic flavor may occur. Doses of 0.1 kGy and above result in a delay of ripening of tomatoes [43]. 

Rubber Stoppers, cap liners, and bulbs for dropper assemblies used in the pharmaceutical industry are made form rubber. The rubber stopper is used primarily for multiple-dose vials and disposable syringes. The rubber polymers most commonly used are natural, neoprene, and butyl rubber. As certain performance expectations... 

To minimize the heat transfer problem occasioned by the high rates of polymerization encountered, the dilatometers were constructed with a surface-to-volume ratio (in the bulb) of approximately 6 to 1. This was achieved by constructing thin, long rectangular paddle-like bulbs, 8.5 cm. long by 2.5 cm. wide by 0.5 cm. thick. This design also assures uniformity of radiation dose rate from front to rear of the sample. 

As an expectorant for coughs and all bronchial affections. Is used generally to allay irritation of mucous surfaces. Dose, 2 to 10 grains of the powdered bulb. Large doses produce emesis. 

The stirrer and dropping funnel are removed, and a thermometer is inserted in one neck of the flask by means of a stopper so that the bulb is well below the surface of the reaction mixture. A 10-mm. bent glass tube is attached to the second neck by a rubber stopper and attached through a trap to a water aspirator (Note 4). The third neck is dosed with a stopper, and the flask... 

The technique of gas adsorption manometry is now probably the most widely used it is simple and effective since the pressure transducer provides all the information required to determine the adsorption isotherm. Thus, the pressure and temperature of each dose of gas are measured and the gas is allowed to enter the adsorption bulb. After adsorption equilibrium has been established, the amount adsorbed is calculated from the change in pressure. The most critical features of adsorption manometry are summarized in the following checklist, with more detailed comments given in Section 3.4. 

Gas released from adsorbent bulb into dosing volume and time allowed for equilibration. 

Adsorption bulb and dosing volume evacuated and sample bulb isolated. 

As we have already seen, for the application of most manometric techniques for the determination of the amount adsorbed it is necessary to have an accurate knowledge of the volumes of two parts of the overall dead space. The first is the connecting volume located between the stopcock above the adsorbent bulb and the lowest valve of the dosing volume (see Figure 3.2). The second, and more important, volume is that of the dead space within the adsorbent bulb. Although the connecting volume does not need to be determined for each experiment, its value can be checked in the first stage of the gas expansion calibration procedure. 

Determination of the volume Vt of the empty bulb at ambient temperature (i.e. in the air thermostat) by expansion of gas from the dosing volume. 

In preliminary studies by Rollins et al., single and multiple oral doses of codeine were administered to drug-free volunteers. After a single dose, codeine was present in the hair bulb within 30 min and peak concentrations were observed at 2 h. The concentration of codeine in the hair bulb decreased over 48 h following a single dose and over 4 weeks following multiple doses. The concentration of codeine in distal hair segments reached a relatively steady concentration within 3 weeks. It was concluded that codeine is rapidly distributed into the hair bulb and a portion is distributed back into the plasma only a fraction is permanently incorporated into hair. 

It is recommended that, where small bore capillary tube has to be melted and blown, a rubber policeman or stoppered rubber tube be attached to the open end of the capillary glass and squeezed to blow up a bulb on the heated dosed end. This bulb can then be blown out by mouth pressure and prepared for further work (see Fig. 3.2). 

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