Split-fraction concept

The procedure is based on the theory of recycle processes published by Nagiev (1964). The concept of split-fractions is used to set up the set of simultaneous equations that define the material balance for the process. This method has also been used by Rosen (1962) and is described in detail in the book by Henley and Rosen (1969). 

Cyclicity of administration is vital in the use of 5-FU as a radiosensitizer. The concept of cyclical treatment has been well established in cancer chemotherapy and alien to classical radiation therapy (where it is termed split-course therapy). 5-FU radio-sensitizes tumor tissue as well as normal cells. However, this normal tissue radio-sensitizationis limited to the irradiated field. Suitable fractionation (i.e., cyclical therapy) can permit rapid normal tissue recovery (23). The results of infused 5-FU and radiation in head and neck cancer supports the principle that cyclical treatment with 5-FU does not suffer from the limitations apparent in split-course radiation treatments. 

The fractional step, or time splitting, concept is more a generic operator splitting approach than a particular solution method [30, 211, 124, 92, 49]. It is essentially an approximate factorization of the methods applied to the different operators in an equation or a set of equations. The overall set of operators can be solved explicitly, implicitly or by a combination of both implicit and explicit discretization schemes. 

The fractional step, or time splitting, concept can be adapted to the discretized equation by splitting the discrete scalar equation into a three step method ... 

The fractional step concept applied to the scalar equations consists of successive applications of the methods for the different operators determining parts of the transport equations. The convective and diffusive terms are further split into their components in the various coordinate directions as explained in sect 12.9.4. 

First, you specify the split you would like. To do this, you need the concept of a light key and heavy key. First, line the chemicals up in order of their boiling points, from low to high. (Note This illustration assumes that the thermodynamics are ideal, so Raoult s law applies.) Because you are using distillation, if most of the propane is to go out in the top stream, a little of the /-butane will, too very small fractions of the other species will go out in the top stream. You want most of the /-butane to go out of the bottom. Thus, you draw a line between propane and /-butane in Table 6.1. The component above the line is the light key and the component below the line is the heavy key. The distillation column is based on those two components, and the other components are split according to thennodynamics. 

Oxidation number is a formal concept adopted for our convenience. The numbers are determined by relying on rules. These rules can result in a fractional oxidation number, as shown here. This does not mean that electronic charges are split. 

Until recently, the rheological measurements were confined to test labs for quality control, research, and development purposes. New techniques for on-line rheological measurements have been developed, bringing the analytical instrumentation to the production floor. This is accomplished by employing a closed-loop instrument which diverts a portion of the process stream to a measurement head and then returns it to the process. Within the measurement head, most of the material flows through a bypass channel and a fraction of the stream is pumped across a capillary die, using precision gear pumps. A similar concept, employed by another manufacturer, utilizes a slit die to measure viscosity. An open-loop on-line rheometer, which does not return the diverted melt stream to the process after measurement, splits the diverted melt stream to two capillary dies of different LID ratios... 

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