Longitudinal dispersion of radioactive substances in Federal waterways

Kerntechnik ◽  
2007 ◽  
Vol 72 (4) ◽  
pp. 205-213 ◽  
Author(s):  
W. J. Krause ◽  
W. Speer ◽  
T. Lüllwitz ◽  
M. Cremer ◽  
W. Tolksdorf
Keyword(s):  
Longitudinal Dispersion ◽  
Radioactive Substances

Radiation Mould with Radio Isotope Solutions Fluid „Iso-mould”

1961 ◽  
Vol 1 (03) ◽  
pp. 246-257
Author(s):  
M. O. Roxo-Nobre ◽  
D. M. Vizeu
Keyword(s):  
Clinical Practice ◽  
Remote Control ◽  
Lymph Nodes ◽  
Half Life ◽  
Radioactive Substances

SummaryA technique of mouldage, employing fluid radioactive substances is adopted, to replace the radium-moulding in the treatment of large surfaces. The technique is explained in detail, proving its greater safety by remote control and an adjustment of adequate means of protection. Distribution is obtained by means of a serpentine attached to the mould in question, which follows the Paterson-Parker system. The authors believe the distribution of radiation on curved anatomical areas to be much more uniform by mould system than any other process of application of the same radiation of rectilineal propagation, transmitted at greater focus-skin distances. The isotopes used up to now were the La140 and others of reduced half-life, in order to prevent the danger of eventual contaminations. Although the application of the process still has very little clinical practice, the technique is presented with a view to experimentation in extensive superficial tumours, or those of little depth, such as tumours of the skin, breast, penis, thyrreoid and lymph nodes.

The effects of surcharged manholes on the travel time and dispersion of solutes in sewer systems

1995 ◽  
Vol 31 (7) ◽  
pp. 51-59 ◽  
Author(s):  
Ian Guymer ◽  
Rob O'Brien
Keyword(s):  
Travel Time ◽  
Moment Method ◽  
In Situ Measurements ◽  
Time Change ◽  
Longitudinal Dispersion ◽  
Laboratory System ◽  
Environmental Load ◽  
Hydraulic Characteristics ◽  
Sewer Systems

Previously, the design of sewer systems has been limited to studies of their hydraulic characteristics, in particular the ability of the system to convey the maximum discharge. Greater environmental awareness has necessitated that new designs, and some existing schemes, are assessed to determine the environmental load which the scheme will deliver to any downstream component. This paper describes a laboratory programme which has been designed to elucidate the effects of manholes on the longitudinal dispersion of solutes. A laboratory system is described, which allows in situ measurements to be taken of the concentration of a fluorescent solute tracer, both up- and down-stream of a surcharged manhole junction. Results are presented from a preliminary series of studies undertaken for a single manhole geometry over a range of discharges, with varying levels of surcharge. Results are presented showing the variation of travel time, change in second moment of the distribution and of a dispersion factor with surcharge, assuming a Taylor approach and determining the dispersion factor using a ‘change in moment’ method. The effect of the stored volume within the manhole is clearly evident. The limitations and the applicability of this approach are discussed.

An investigation of fine sediment mixing within free-flowing and surcharged manholes

1998 ◽  
Vol 37 (1) ◽  
pp. 215-222
Author(s):  
I. Guymer ◽  
R. O'Brien ◽  
O. Mark ◽  
P. Dennis
Keyword(s):  
Dead Zone ◽  
Laser Induced Fluorescence ◽  
Fine Sediment ◽  
Longitudinal Dispersion ◽  
Qualitative Description ◽  
Suspended Material ◽  
Mixing Processes ◽  
Future Developments ◽  
Mixing Effects ◽  
Sediment Mixing

Previous studies of the effects of manholes on longitudinal dispersion has concentrated on the spreading of solutes. This papers presents new data describing the influence of a surcharged and free-flowing manhole structure on the longitudinal dispersion of a fine suspended material. The effects of benching within the manhole structure are also illustrated. Laser Induced Fluorescence (LIF) techniques have been used to provide a qualitative description of the mixing processes present within a surcharged manhole. Nephelometric results have provided estimates of the parameters required to simulate the mixing effects using either increase in variance or aggregated dead zone techniques. A preliminary attempt at describing these observations using available software is discussed and recommendations for future developments are made.

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