SFT (Sequential Fragmentation/Transport)


KWare -Geological Software
 Ken Wohletz

Current Version: 2.19.0170* (26 November 2013)

* New version allows data input from -10 phi (~1 meter) to 15 phi (30 nanometers) and display of cumulative curve data.


SFT is a WindowsTM application designed to invert particle size data to find size distribution parameters of lognormal, sequential fragmentation, or sequential fragmentation/transport parameters, the latter two providing information about the fragmentation/transport origins of the sample (Wohletz et al., 1989, Jour Geophys Res 94: 15703-15721).

A publication in the Journal of Applied Physics [78(4), 15 August 1995, 2758-2763] describes the connection between SFT and the Weibull, Rosin-Rammler, and lognormal distributions.

SFT has been experimentally applied to products of Fuel-Coolant Interactions (FCI), which are analogs for hydrovolcanism. This work and field applications (e.g., the Neapolitan Yellow Tuff) have illustrated the utility of SFT for applications to volcanic particulate samples. Wilbur Brown has also demonstrated it use for a wide variety of samples including the initial mass function of stars, high explosive aerosols, meteoritic debris, the asteroids, and ball-mill products (Brown, 1989, J. Astrophys. Astron. 10, 89-112) With these successes we have investigated other applications, including a study of the size distribution of the tectonic plates.

The following screen shots illustrate what SFT does. This first picture shows the data entry form where the user enters data by phi-fraction (for logarithmically spaced data bins collected by sieves) or by non-standard data where bin data are for specific size intervals.

Pressing "Analyze..." takes the user to the distribution curve-fitting window where lognormal- or SFT-type curves can be fit to a cubic spline curve representation of the data. Here best-fits can be established and SFT parameters defined. The SFT parameters can then be put into a spread sheet to derive fragmentation and transport correlations that help uncover the history of the sample.

Alternatively, for a more traditional approach to granulometry, the user may choose to show the cumulative curve display and statistics.


KWare SFT software (LA-CC 99-29; Copyright 1999 UC) is available as self-installing files for downloading for 32-Bit Windows operating systems:

Download for Windows 32- and 64-bit systems: SFT_Install, (version 2.19.0170, ~3.2 MB, 26 November 2013).

DISCLAIMER: The development of these programs was sponsored by the United States Government. Neither the United States Government, nor the United States Department of Energy, nor the University of California, nor any of their employees makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. References herein to any specific commercial product, process, or service by trade name, mark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.