Period, injection

Lenhoff, J. Chromatogr., 384, 285 (1987)] or by direct numerical solution of the conservation and rate equations. For the special case of no-axial dispersion with external mass transfer and pore diffusion, an explicit time-domain solution, useful for the case of time-periodic injections, is also available [Carta, Chem. Eng. Sci, 43, 2877 (1988)]. In most cases, however, when N > 50, use of Eq. (16-161), or (16-172) and (16-174) with N 2Np calculated from Eq. (16-181) provides an approximation sufficiently accurate for most practical purposes. 

Figure 4.67 Periodic injection of 4-bromobenzonitrile into a continuous phenylboronic acid stream. Product yield is plotted as a function of injection interval [6, 7. ...

Periodically injecting simultaneously or alternately a noncondensable gas and a foaming composition solution containing alkalis, surfactants and polymers to form combined foam or periodically injecting the gas and the foam previously formed from the solution... 

Thus the response to a periodic injection for very general boundary conditions can be found by substituting p = +iu into Eq. (34). The results for the general case would be very complicated so, as an illustration of the form of the periodic response, we will consider only the simplest case a doubly infinite system. For such a system, = H/ = Dii,, and Eq. (34) reduces to... 

ISOTEC is a technology that uses the periodic injection of hydrogen peroxide and proprietary catalysts to oxidize organic contaminants in situ. According to the vendor, this technology can treat soil and groundwater contaminated with chlorinated compounds, petroleum hydrocarbons, polychlorinated biphenyls (PCBs), trichloroethene (TCE), tetrachloroethene (PCE), pesticides, herbicides, as well as benzene, toluene, ethylbenzene, and xylene (BTEX). The ISOTEC technology is commercially available. 

This simple method is used in industry for repetitive analyses. For such analyses, the chromatograph must be equipped with an autosampler, including a sample tray and an automatic injector. The single reference solution, periodically injected for control purposes, can be used to compensate for baseline drifts. It is not necessary to add an internal standard to each of the samples, as discussed below. 

When Ce(IV) is consumed during polymerisation its concentration will drop. The amount consumed is expected to be inversely proportional to the number of radicals formed in the solution. Samples from the cell solution in which the polymerisation reaction takes place were periodically injected... 

In the dual-pressure process, low to medium pressure gases (0.3 to 0.6 MPa) containing nitrogen oxides are compressed to 1.1 to 1.5 MPa for efficient absorption in water to make nitric acid. Because of the potential for unreacted ammonia from the converter to combine with nitric acid to form ammonium nitrate, additional operating and safety precautions are necessary to deal with the accumulation of ammonium nitrate solids. One reported solution is a periodic injection of steam to parts of the compressor (see Figure 9.3)104. 

The acetylated lignin, dissolved in 1.0 ml of dioxane containing 5 mg of an internal standard, is treated with 1.0ml of a dioxane-pyrrolidine (1 1, v/v) solution which initiates the aminolysis reaction. The rate of the 1-acetylpyrrolidine formation is followed by periodically injecting 1-2/d of the reaction mixture into the gas chromatograph. The initial rapid phase is generally complete within 20 min, but a total of 60min is required to complete the deacetylation process. 

Transfer of ion exchanger into the operating section is effected with solution periodically injected through valve 10. The empty space is filled with a suspension of ion exchanger injected through jet 14. Excess solution is removed through filter 4. 

FA can easily be treated with large oral dtrses of hydroxocobalamin (1 mg/day) Or with periodic injections of the vitamin (1 mg/month). Absorption of the small fraction of the large oral dose occurs by non intrinsic factor-dependent mechanisms and can satisfy the vitamin requirement. Treatment must be continued throughout life. 

The periodic injection of the sample into the flowing carrier stream creates a heterogeneous composition in the carrier stream. The detector will normally see the undiluted carrier stream flowing past it. The sample bolus will, however, pass the detector at intervals and cause a response to the analyte species. The output of the detector is a normally flat baseline interspersed with peak-shaped responses shordy following each sample injection (Figure 1). 

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