Synthetic fluxes

Figure 4. Spectra for a variety of synthetic flux grown and melt pulled forsterites. For both, the positions of the Cr and Mn emissions match closely those of meteoritic forsterites.

Menger FM et al (1990) Synthetic flux-promoting compounds - exceeding the iontransporting ability of gramicidin. J Am Chem Soc 112 2451-2453... 

Emerald synthetic-flux grown Match 13.17 Color Green Group Beryl... 

Bhowmik PC, DoU JD (1983) Growth analysis of com and soybean response to allelopathic effects of weed residues at various temperatures and photo synthetic flux densities. J Chem Ecol 9 1263-1280... 

Fig. 4. Schematic diagram of one of the arrangements for the flux-reaction growth of synthetic emerald (2).

Beryl. Beryl [1302-52-9] Be Al Si O g, is called aquamarine [1327-51 -1] when pale green or blue from inclusion of Fe emerald [12415-33-7] when dark green from Cr or at times V, and morganite or red beryl when pink or red, respectively, from Mn. Only the synthetic emerald is in commercial production, although the other colors can also be grown. Both the flux and hydrothermal techniques are used to grow this luxury synthetic. 

Synthetic cryolite solved the supply problem, but synthetic cryolite requires fluorine which is actually more abundant in the Earth s crust than chlorine, but dispersed in small concentrations in rocks. Until the 1960s, fluorspar (CaFj) a mineral long known and used as a flux in various metallurgical operations was the source. A source is phosphate rock that contains fluorine i.s 3% quantity,... 

Flubendiamide is an example of a new chemical class of insecticides that have been termed phthalic acid diamides (Nauen 2006, Copping and Duke 2007). They are related to the alkaloid ryanodine, which is extracted from Ryania species. Ryanodine affects muscles by binding to calcium channels of the sarcoplasmic reticulum. Ca + ions act as intracellular messengers, and their flux is modulated by calcium channels of this type. The toxic action of ryanodine and synthetic insecticides related to it is due to the disturbance of calcium flux. 

Ultrasound can thus be used to enhance kinetics, flow, and mass and heat transfer. The overall results are that organic synthetic reactions show increased rate (sometimes even from hours to minutes, up to 25 times faster), and/or increased yield (tens of percentages, sometimes even starting from 0% yield in nonsonicated conditions). In multiphase systems, gas-liquid and solid-liquid mass transfer has been observed to increase by 5- and 20-fold, respectively [35]. Membrane fluxes have been enhanced by up to a factor of 8 [56]. Despite these results, use of acoustics, and ultrasound in particular, in chemical industry is mainly limited to the fields of cleaning and decontamination [55]. One of the main barriers to industrial application of sonochemical processes is control and scale-up of ultrasound concepts into operable processes. Therefore, a better understanding is required of the relation between a cavitation coUapse and chemical reactivity, as weU as a better understanding and reproducibility of the influence of various design and operational parameters on the cavitation process. Also, rehable mathematical models and scale-up procedures need to be developed [35, 54, 55]. 

Tin slags account for a sizeable fraction of the world s tantalum production. These slags are melted in electric arc furnaces, together with coke and lime (as flux), and this pyrometallurgical process leads to the production of synthetic niobium/tantalum concentrates. The waste products of this operation are mechanically separated slags which can be used, for instance, as landfill. The exhaust gases from this process are of minor consequence if dust is eliminated by the use of filters. 

It must, however, be taken into account that the radiation flux has not always been constant during the 4.6 billion years since the formation of the sun. The solar constant is in fact not a constant at all, as it depends on the state of the sun s surface. For prebiotic syntheses, it is important to consider the wavelengths which can be absorbed by small molecules such as CO2, CO, CH4, N2, NH3, H2O, H2S etc. The premise here, of course, is that most of the synthetic reactions occurred in the gas phase. 

Astronomical Observatory, were used to carry out the calculations of theoretical equivalent widths of lines, synthetic spectra and a set of plane parallel, line-blanketed, flux constant LTE model atmospheres. The effective temperatures of the stars were determined from photometry, the infrared flux method and corrected, if needed, in order to achieve the LTE excitation balance in the iron abundance results. The gravities were found by forcing Fe I and Fe II to yield the same iron abundances. The microturbulent velocities were determined by forcing Fe I line abundances to be independent of the equivalent width. For more details on the method of analysis and atomic data see Tautvaisiene et al. (2001). 

These and other models have been combined to produce a standard library of synthetic stellar flux spectra and colours as a function of effective temperature, gravity and metallicity by Lejeune, Cuisenier and Buser (1997, 1998) and Westera et al. (2002). 

Programs to construct synthetic models combining stellar evolutionary calculations with flux or spectrum libraries include PEGASE, accessible via http //www2.iap.fr/users/hoc/PEGASE.html. 

Espig A process for making synthetic emeralds by the flux reaction technique. Beryllia and alumina are dissolved in molten lithium molybdate, and silica is floated on the melt. The emerald crystals form at the base of the melt, but because they tend to float and mix with the silica, a platinum screen is suspended in the middle of the melt. Invented by H. Espig. 

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