Conversion technique

Metal Finishing and Corrosion Control. The exceptional corrosion protection provided by electroplated chromium and the protective film created by applying chromium surface conversion techniques to many active metals, has made chromium compounds valuable to the metal finishing industry. Cr(VI) compounds have dominated the formulas employed for electroplating (qv) and surface conversion, but the use of Cr(III) compounds is growing in both areas because of the health and safety problems associated with hexavalent chromium and the low toxicity of trivalent chromium (see... 

Crude oil processing is mainly aimed towards the production of fuels, so only a small fraction of the products is used for the synthesis of olefins and aromatics. In Chapter 3, the different crude oil processes are reviewed with special emphasis on those conversion techniques employed for the dual purpose of obtaining fuels as well as olefmic and aromatic base stocks. Included also in this chapter, are the steam cracking processes geared specially for producing olefins and diolefms. 

The slopes of the regression lines for conversion yield against reactive macerals for the hot-rod and for the rotating autoclave modes of hydrogenation are shown by statistical analysis to be similar (compare Figures 9 and 10). This suggests that the relationship between total reactive macerals and coal reactivity as measured by conversion is not dependent on the conversion technique. 

One fuel alternative involves the more widespread use of biomass produced fuels. More efficient biomass conversion techniques would help make biofuels more cost-competitive. Land availability and crop selection are major issues in biomass fuel usage. Biomass alternatives can be expected to grow to a significantly larger scale for providing fuel. 

Methanol and ethanol are alcohol fuels that can be produced from various renewable sources. Alcohol fuels are converted from biomass or other feedstocks using one or several conversion techniques. Both government and private research programs are finding more effective, less costly methods of converting biomass to alcohol fuels. Methanol was originally a by-product of charcoal production, but today it is primarily produced from natural gas and can also be made from biomass and coal. 

Thanks to its versatility, the general approach described hereabove gives a good grip of the synthesis of many different families of block polymers. However, in several cases where the formation mechanisms of the two types of chains are not amenable to this quantitative active end-group conversion technique, a still more general answer is needed. 

Time-resolved fluorescence in the femtosecond time range fluorescence up-conversion technique... 

Chapter 6 described the current techniques employed in time-resolved fluorescence spectrocopy. The time resolution of these techniques ranges from a few picoseconds (streak cameras) to a few hundreds of picoseconds (single-photon timing with flash lamp excitation). The time resolution can be greatly improved by using the fluorescence up-conversion technique. 

The molecular structures of the main biomass constituents are given in Figures 10.8 and 10.9. These structures induce a physicochemical behavior that is markedly different from the behavior of the hydrocarbons contained in crude oil (see Table 10.2). Note that the relative thermal fragility of the biomass molecular structures encourages the chemist to prefer thermally mild and therefore low-energy-consuming conversion techniques such as fermentation or hydrothermolysis to exploit biomass (see Figure 10.10). 

Aravindhababu, R, Mohan, G., Sasikala, J. 1999. Emerging energy conversion techniques for next millennium, in Proceedings National Solar Energy Convention 1999, Indore, 20-22 Dec 1999. Pushpkunj, Indore. 

N. Berkowitz (Alberta Research Council) provided a stimulating account of the potential of coal in Canada s energy future. Coal can be used directly as an industrial fuel or be converted to other combustible hydrocarbons. Berkowitz described the three different conversion techniques gasification, liquefaction, and partial conversion techniques to produce gases, oils, and solid fuels. 

In chemical terms, the simplest conversion technique is the transformation of coal into a combustible gas by gasification. In its earliest form - introduced in Britain ca. i860 by Sir William Siemens - this involved generation of a producer gas, mainly a mixture of CO, CO2 and nitrogen, by incomplete combustion of coal in air, i.e., by... 

The chemistry of a third group of conversion techniques -i.e., partial conversion methods which skim hydrocarbon gases and/or liquids from the coal and leave a char suitable for use as a boiler fuel or gasification feedstock - is. If anything, even more speculative than the chemistry of liquefaction. 

As another example, conversion to furnish either DC or AC, or combinations of either, at whatever frequencies are required, is easily accomplished by standard conversion techniques and add-on systems. 

HOESCHELE, D. F. Analog-to-Digital/Digital-to-Analog Conversion Techniques (Wiley, New York, 1968). 

Sample Rate Conversion Techniques. The simplest form of sample rate conversion is called either drop sample tuning or zero order hold interpolator. This technique is the basis for the table lookup phase increment oscillator, well known in computer music [Moore, 1990a],... 

Sample rate conversion. All of the synchronous pitch shifting techniques essentially involve sample rate conversion techniques. The theory and practice of sample rate conversion has received extensive coverage in many excellent texts and articles, but it is illuminating to compare the computer music perspective with the traditional sample rate conversion literature. Insights from the sample rate conversion literature provide insights to the computer music perspective, and vice versa. 

As already indicated Eq. (39) (Eq. (40)) gives the rate of ideal time and frequency resolved emission. If compared with experimental data gained by single photon counting, F(iv t) has to undergo a time averaging with the respective apparatus function which determines the possible time resolution of the measurement (for up conversion techniques see [44]). 

In order to learn about the true quantum efficiency of photogeneration one therefore has to study the photoinduced charge generation mechanism at faster time scales. Pump probe spectroscopy utilising a few optical-cycle laser pulses (5-6 fs) in the visible spectral range with broadband frequency conversion techniques [89] now makes it possible to study extremely fast optically-initiated events with unprecedented time resolution. Such a setup was used to time-resolve the kinetics of the charge transfer process from a polymer chain to a fullerene moiety in thin films of poly[2-methoxy, 5-(3, 7 -dimethyl-octyloxy)]-p-phenylene vinylene (MDMO-PPV) and [6,6]-phenyl C6i butyric acid methyl ester (PCBM). Solutions prepared from 1 wt% solutions of toluene on thin quartz substrates were studied. 

A more direct way of exploring the dynamics of polar solvent in the presence of a solute is by the optical excitation of a solute to an intramolecular charge transfer state and then observing the time-dependent fluorescence, as shown in Fig. 1.7 [47, 52]. To follow the time-dependent fluorescence at short times, faster than the usual fluorescent lifetime of nanoseconds, lasers plus an up-conversion technique were used. A quantity frequently measured is the dynamic Stokes shift S(r),... 

The following aromatics conversion techniques have produced developments leachmg the industrial level ... 

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