Revision techniques

Lloyd, D.C., J.S. Prosser, and R.J. Purrott, The Study of Chromsome Aberrations Yield in Human Lymphocytes as an Indicator of Radiation Dose Revised Techniques, NRPB-M70, National Radiological Protection Board, Chilton, Didcot, Oxon. 0X11 0RQ, Great Britain, (November 1982). 

Revision techniques are covered in the sections on revision and memory earlier in this chapter. 

For purposes of this description, a flow of 5,000 gpm and a head rise through the pumping system of 250 feet will be considered. A shaft speed of 1750 RPM will be chosen and the NPSH established. In order to do this, the maximum suction specific speed must be considered. For more or less conventional types of impellers a maximum of 15,000 is a reasonable value of suction specific speed, resulting in a required NPSH of 16.7 feet. Using revised techniques, a value of 30,000 can be achieved, resulting in an NPSH requirement of 6,6 feet. A maximum achievable limit at the present time of 40,000 suction specific speed will result in an NPSH requirement of 4. 5 feet. 

The model is meant to be relatively open to the evolution of NDT techniques. Thus, a normal evolution of the standard is to include, in future revisions, as "standard devices" some devices which have proved to be of current use. Two other axes of evolution are the handling of processed data and of simulated data. 

The atmospheric movement of pollutants from sources to receptors is only one form of translocation. A second one involves our attempt to control air pollutants at the source. The control of parhculate matter by wet or dry scrubbing techniques 3delds large quantities of waste materials—often toxic—which are subsequently taken to landfills. If these wastes are not properly stored, they can be released to soil or water systems. The prime examples involve the disposal of toxic materials in dump sites or landfills. The Resource Conservation and Recovery Act of 1976 and subsequent revisions are examples of legislation to ensure proper management of solid waste disposal and to minimize damage to areas near landfills (4). 

Within 6 months after enactment of the Qean Air Act Amendments of 1990, and at least every 3 years thereafter, the Administrator shall review and, if necessary, revise, the methods ( emission factors ) used for purposes of this Act to estimate the quantity of emissions of carbon monoxide, volatile organic compounds, and oxides of nitrogen from sources of such air pollutants (including area sources and mobile sources). In addition, the Administrator shall permit any person to demonstrate improved emissions estimating techniques, and following approval of such techniques, the Administrator shall authorise the use of such techniques. Any such technique may be approved only after appropriate public participation. Until the Administrator has completed the revision required by this section, nothing in this section shall be construed to affect the validity of emission factors established by the Administrator before the date of the enactment of the Clean Air Act Amendments of 1990. 

Modern measuring techniques, an increased requirement for the indoor environment, and the efficiency of filters in separating particles led to EUROVENT 4/9 1992 Method of Testing Air Filters Used In General Ventilation for the Determination of Fractional Efficiency. This method also provides the basis for the next revision or upgrade of European Standard EN 779 1999. 

Review the techniques periodically and revise them (if necessary) to take advantage of new developments in the field. 

Chiral Separation Techniques A Practical Approach, Second, completely revised and updated edition... 

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