Fountains compositions

Titanium is therefore an important ingredient in fountain compositions. It is characterised as a non-volatile metal with non-volatile oxides. The particles are easily ignited, even in the form of large flitters , and once ignited they grow progressively brighter and finally explode in a spectacular star formation. 

Charcoal is used in excess because the decomposition of the extra charcoal is endothermic, the overall effect being to lower the exothermicity of the fountain composition and so reduce the burning rate. However, the main advantage in using extra charcoal is that a reducing atmosphere is produced within the fountain such that the possible reaction of the emitter prior to ejection is greatly reduced. 

Some fountain compositions tend to be oxidant-rich due to the presence of excess potassium nitrate or sometimes various oxalates. The reason for this is to reduce the burning rate and/or to enhance the visual effects. Certainly if gunpowder is considered to be a mixture of fuels (charcoal and sulfur) and oxidant (potassium nitrate) then the maximum rate of burning should coincide with a slightly under-oxidised system. The burning rate is therefore reduced by adding excess nitrate to the system. 

Wire sparklers are wires coated with pyrotechnic composition which are hand-held and produce a gende spray of gold sparks from iron filings. Fountains are cardboard tubes filled with chemical mixtures that produce a spray of color and sparks extending 2—5 m into the air. Roman candles are cylindrical tubes which repeatedly fire colored stars distances of 5—20 m into the air. These items typically contain 5—12 stars. 

Rubin KH, Wheller GE, Tanzer MO, MacDougall JD, Vame R, Finkel R (1989) decay series systematics of young lavas from Batur volcano, Sunda arc. J Volcanol Geotherm Res 38 215-226 Rudnick RL, Fountain DM (1995) Nature and composition of the continental cmst a lower cmstal perspective. Rev Geophys 33 267-309... 

Since we have no direct information about the chemistry of the Fountain fluid, we assume that its composition reflects reaction with minerals in the evaporite strata that lie beneath the Lyons. We take this fluid to be a three molal NaCl solution that has equilibrated with dolomite, anhydrite, magnesite (MgCC>3), and quartz. The choice of NaCl concentration reflects the upper correlation limit of the B-dot (modified Debye-Hiickel) equations (see Chapter 8). To set pH, we assume a CO2 fugacity of 50, which we will show leads to a reasonable interpretation of the isotopic composition of the dolomite cement. 

Table 25.2. Predicted compositions of Lyons groundwater and Fountain brine, before mixing (Lee and Bethke, 1994)...

To calculate the composition of the Fountain brine, we start anew in react, enter the commands... 

We then set the isotopic compositions of each oxygen and carbon-bearing component in the reactant, the Fountain brine, to < 180 and 813C values of zero, as... 

Fig. 25.4. Oxygen and carbon stable isotopic compositions of calcite ( ) and dolomite ( ) cements from Lyons sandstone (Levandowski et al., 1973), and isotopic trends (bold arrows) predicted for dolomite cements produced by the mixing reaction shown in Figure 25.3, assuming differing CO2 fugacities (25, 50, and 100) for the Fountain brine. Fine arrows, for comparison, show isotopic trends predicted in calculations which assume (improperly) that fluid and minerals maintain isotopic equilibrium over the course of the simulation. Figure after Lee and Bethke (1996).

Tubular membranes of 8 long were prepared from blend composition consisting of CA and PMMA and performance data for one month operation was collected. These datas show high product water flux (18-20 gfd.) with low flux decline slope. However, it was observed that these membranes initially showed fountains" which disappeared in about 30 minutes time. This was attributed to the peculiar membrane rheology and orientation of PMMA molecule with respect to CA molecule. This needed further study for confirmation. 

Composite Materials Department, Ciba-Geigy Corporation, Fountain Valley, CA 92708... 

Although the compositions used in fountains are usually based on black powder propellant, the sparks that are responsible for the fountain effect originate from other substances within the composition. These substances are known as emitters and it is the physical and chemical properties of the emitters that determine the characteristics of the fountain. Various additives are also used to promote the visual effects or to cheapen the composition. 

More exotic effects call for more exotic materials, and considerable effort has gone into formulating compositions that are both spectacular in effect and safe to produce and handle. Thus a 30 mm fountain might contain mealed (or hue) gunpowder, potassium nitrate, sulfur, charcoal, antimony trisulhde, barium nitrate, hue aluminium and flitter aluminium with a dextrin binder. This composition is certainly a good deal more complicated than that used for sparklers but is relatively safe to produce and gives a good burst of white sparks. 

Mare basalts include lavas that erupted from fissures and pyroclastic deposits that produced glass beads. Six of the nine missions to the Moon that returned samples included basalts. The mare basalts from different sites have distinctive compositions and are classified based on their Ti02 contents, and to a lesser extent on their potassium contents (Fig. 13.3). A further subdivision is sometimes made, based on A1203 contents. Mare basalts are compositionally more diverse than their terrestrial counterparts. Volcanic glass beads, formed by fire fountains of hot lava erupting into the lunar vacuum, were found at several Apollo sites and eventually were shown to be a constituent of virtually every lunar soil. The glasses are ultramafic in composition and formed at very high temperatures. 

Rudnick R. L. and Fountain D. M. (1995) Nature and composition of the continental crust a lower crustal perspective. Rev. Geophys. 33, 267-309. 

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