Inefficiency, sources

The Grignard method was the first route used commercially in the production of silicone intermediates. Its great advantage is its extreme flexibility since a wide range of organic groups may be attached to the silicon in this method. Because of the need to use ether or other inflammable solvents considerable production hazards arise. On economic grounds the main drawbacks of the process are the multiplicity of steps and the dependence on silicon tetrachloride, which contains only 16% Si and is thus a rather inefficient source of this element. 

The toxicity of barium compounds depends on their solubility, with the more soluble forms being more toxic than the relatively insoluble forms, which are inefficient sources of Ba ions. ... 

When evaluating the health effects of barium compounds, it is important to keep in mind that different barium compounds have different solubilities in water and body fluids and therefore serve as variable sources of the Ba + ion. The Ba + ion and the soluble compounds of barium (notably chloride, nitrate, hydroxide) are generally highly toxic to humans and experimental animals. The insoluble barium compounds (notably sulfate and carbonate) are inefficient sources of the Ba + ion and therefore are generally nontoxic. Throughout the following section (2.2), the health effects by route of exposure of both soluble and insoluble barium compounds are discussed. 

A normal gas discharge is a relatively inefficient source for ions, since only a few percent of the gas particles are ionized. 

This remixing which occurs in both sequences of simple distillation columns is a source of inefficiency in the separation. By contrast. 

Waste from steam systems. If steam is used as a hot utility, then inefficiencies in the steam system itself cause utility waste. Figure 10.9 shows a schematic representation of a steam system. Raw water from a river or other source is fed to the steam system. This is... 

Prior to the introduction of ESI, ms /ms studies of peptides were generally limited to molecules mol wt < 3500 (33). This limitation was a consequence of the rapid drop in precursor ion intensity from Isims ion sources with increasing mass, and the inefficiency of coUisional activation. Good... 

The suitabiHty and economics of a distillation separation depend on such factors as favorable vapor—Hquid equiHbria, feed composition, number of components to be separated, product purity requirements, the absolute pressure of the distillation, heat sensitivity, corrosivity, and continuous vs batch requirements. Distillation is somewhat energy-inefficient because in the usual case heat added at the base of the column is largely rejected overhead to an ambient sink. However, the source of energy for distillations is often low pressure steam which characteristically is in long supply and thus relatively inexpensive. Also, schemes have been devised for lowering the energy requirements of distillation and are described in many pubHcations (87). 

Even the best modern low-temperature air separation plant has an efficiency only a small fraction of the theoretical optimum, that is, about 15 to 20 percent. The principal sources of inefficiency are threefold (1) the nonideality of the refrigerating process, (2) the imperfection of the heat exchangers, and (3) losses of refrigeration through heat leak. 

Could poor mixing or inefficient distribution of reactants and heat sources result in undesirable side reactions, hot spots, runaway reactions, fouling, etc ... 

It is likely that the reliable crude oil supply will not diminish any time soon. Petroleum-derived fuels will remain the primary source of transportation energy for well into the twenty-first century. Producers and refiners have been, and will be, environmentally responsible. The existing infrastructure of advanced product distribution systems can compete with alternative fuels readily. Future fuels will be competitive, both economically and environmentally. New global market conditions will dictate closure of inefficient facilities and investment in new technology. Larger and more efficient operations will survive and will focus on the niche market. ... 

Bromamine-T can also be utilized as a nitrene source, as reported by Zhang et al. [27]. Fe(in) porphyrins such as Fe(TPPC)Cl (Figure 4.2) thus catalyze the aziridination of alkenes when bromamine-T is used, whereas chloramine-T was inactive and iodinanes were inefficient reagents. 

In the case of a slow protonation rate (with inefficient proton donors and/or low concentrations of the proton source), the alternative could be an EECC mechanism through a disproportionation process, still at the potential of the first step. 

Due to diffraction effects of micron-sized mirrors in a regular array, commonly used techniques for surface characterization based on interferometry are inefficient. To overcome the diffraction effects we have developed a novel surface characterization method with an incoherent light source, based on the Foucault s knife-edge test (Zamkotsian and Dohlen, 1999). Since Leon Foucault introduced the knife-edge test in the last century (Foucault, 1859), it has been widely used for testing optical surfaces (see Ch. 3). The test offers a simple way of obtaining easily understandable, qualitative information of the surface shape. 

There is a temptation to fix problems when they occur rather than to eliminate the source of the problem. End-of-pipe or end-of-Iife solutions are superficially attractive because you don t have to go back and repeat work which has already been done. However, it is often both environmentally and financially inefficient. Often technical fix is piled upon technical fix until the entire system coUapses. Deep innovation thinking is more demanding but offers fhe chance fo leapfrog competition. 

The weakness of MC-ICPMS lies in the inefficiency by which ions are transferred from the plasma source into the mass spectrometer. Therefore, despite very high ionization efficiencies for nearly all elements, the overall sensitivity (defined as ionization plus transmission efficiencies) of first generation MC-ICPMS instruments is of the order of one to a few permil for the U-series nuclides. For most, this is comparable to what can be attained using TIMS. 

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