Measurement, magnesium oxide

The present authors have had experience using rotary samplers for field studies involving relatively small droplets for vector control applications and for the measurement of droplet size at far-field distances. When using magnesium oxide slides, the spread factor for droplets varies from 0.75 for crater diameters up to 15 jam, to 0.8 for 15-20 p.m and 0.86 for crater diameters above 20 am. 

Note that similar measurements were performed in [30] for the case of evaporation of defect atoms of lead from lead oxide, atoms of magnesium from magnesium oxide, and so on. 

The actual determination of color is made with a photoelectric tristimulus colorimeter fitted with a CIE illuminating source. Measurements are made relative to a standard (usually magnesium oxide or barium sulfate) taken through... 

Following the original measurements of the surface energy of sodium chloride by heats of solution by Lipsett et al. 18), much more accurate determinations have been carried out recently by Benson and his co-workers 19-22). Other substances which have been investigated include magnesium oxide 23), calcium oxide and hydroxide 24), and silica, unhydrated and hydrated 25). 

A final factor that can limit the temperature of pyrotechnic flames is unanticipated high-temperature chemistry. Certain reactions that do not occur to any measurable extent at room temperature become quite probable at higher temperatures. An example of this is the reaction between carbon (C) and magnesium oxide (MgO). Carbon can be produced from organic molecules in the flame. 

In this section we compare the theory of the preceding two sections with experimental measurements of infrared extinction by small particles. Comparisons between experiment and theory for spheres of various solids, most notably alkali halides and magnesium oxide, have been published in the scientific literature many of these papers are cited in this chapter. In most of this work, however, there is an arbitrary normalization of theory and experiment, which tends to hide discrepancies. For this reason, most theoretical calculations in this section are compared with mass-normalized extinction measurements. The new measurements presented here were made in the Department of Physics at the University of Arizona. A group of solids was selected to illustrate different aspects of surface modes. Results on amorphous quartz (Si02) particles, for example, illustrate the agreement between experi-... 

Bulk matter, rather than particles, is the subject of Part 2. In Chapter 9 we discuss classical theories of optical properties based on idealized models. Such models rarely conform strictly to reality, however, so Chapter 10 presents measurements for three representative materials over a wide range of frequencies, from radio to ultraviolet aluminum, a metal magnesium oxide, an insulator and water, a liquid. 

Anhydrous VO(aca)2 was prepared as described in the literature.44 Analyzed VOSfVSHjO was obtained from Struers Co., Copenhagen. Solntion spectral measurements were made using a Zeiss instrument. Reflectance spectra were obtained with a Beckman DU equipped with a standard reflectance attachment. Magnesium oxide was used as a standard. The resolution of the bands in the reflectance spectrum of VOS0< 5H 0 did not differ from the resolution achieved for the crystal absorption spectrum A shown in Fig. 5. 

A certain quantity of the spirit (e.g., 300 c.c.), together with the rinsings of the measuring vessel, is distilled with a few drops of sodium hydroxide solution or a little magnesium oxide to remove the fixed matters aud the colouring materials and to liberate the pyridine bases in case these are present partly as salts the amount of distillate collected is that of the spirit taken. 

In both calcium carbonate and magnesium carbonate, which may be formulated CaO-C02 and MgO-C02, we have the same acid anhydride, C02. The tenacity with which the basic anhydrides CaO and MgO hold this acid anhydride is a measure of their basic strength. Magnesium oxide is, therefore, less strongly basic than calcium oxide. 

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