Los Alamos National Laboratory
Profile Pages
Scott Hansen
Expertise
I am an applied mathematician and hydrogeologist with expertise concerning a wide variety of topics and techniques. These include inverse problems, integral transforms, DNAPLs, mobileimmobile zone methods, anomalous transport, random walks (including CTRW), and heterogeneous porous media. Some areas in which I have focused my efforts are highlighted below, each accompanied by a list of related accomplishments:
Contaminant hydrogeology
 Developed an analytic solution for dissolution of residual multicomponent NAPL.
 Developed an analytic solution for firstorder decay chains in parallel, discrete fractures.
 Developed a Laguerre functionbased technique for grafting arbitrary, time varying Type I boundary conditions onto analytic transport models.
 Developed computational suite for analysis of coupled dissolution and subsurface transport.
 Studied the weathering of creosote in the subsurface, and showed the possibility of PAH and phenolic plumes emanating from a single source NAPL body becoming disjoint.
 Studied the forensic identification of Aroclors (commercially available PCB mixtures), and showed the infeasibility of identifying them in the absence of inverse transport models.
Random walk methods
 Developed the RPCTRW technique, a simplified continuoustime random walk (CTRW) approach for modeling upscaled advective transport in heterogeneous media.
 Derived a nonconservative generalized master equation for anomalous transport subject to A + B > 0 reactions.
 Presented a new, nonconstructive proof of the reflection principle for 1D random walks on a lattice.
Reactive transport
 Developed reactive particle tracking codes for diffusionreaction systems.
 Derived a threeway relationship between reaction radius for fixedradius reactive PT schemes, the mass action law for reactiondiffusion equations, and Fickian diffusion constant (assuming mixinglimited conditions).
 Incorporated bimolecular reaction into the CTRW for anomalous dispersionreaction systems (under ratelimited conditions).
Education

Ph.D. (Civil Engineering), Queen's University, 2012
M.Sc. (Mathematics), University of Toronto, 2007
B.Sc. (Mathematics and Engineering), Queen's University, 2004
LANL Positions

Postdoctoral Research Associate (EES16), 2015Present
Awards

Major recent awards:
2013 – 2015 Azrieli Foundation  Postdoctoral Fellowship
2013 Weizmann Institute of Science  Dean of Faculty Postdoctoral Fellowship
2009 – 2012 Natural Science and Engineering Research Council [Canada]  Alexander Graham Bell Canada Graduate Scholarship
Publications

The following are my refereed journal publications as of June 2015. Uptodate information is listed on Google Scholar:
S.K. Hansen and B. Berkowitz (2015). Integrodifferential formulations of the continuoustime random walk for solute transport subject to bimolecular A + B → 0 reactions. Physical Review E 91, 032113.
S.K. Hansen and B. Berkowitz (2014). Interpretation and nonuniqueness of CTRW transition distributions: insights from an alternative solute transport formulation. Advances in Water Resources 74, pp. 54–63.
S.K. Hansen, H. Scher and B. Berkowitz (2014). Firstprinciples derivation of reactive transport modeling parameters for particle tracking and PDE approaches. Advances in Water Resources 69, pp.146–158.
S.K. Hansen and B.H. Kueper (2014). A new model for coupled multicomponent NAPL dissolution and aqueousphase transport, with application to creosote dissolution in discrete fractures. Water Resources Research 50, pp. 58–70.
S.K. Hansen (2013). Semianalytic solution for transport of a twomember decay chain in discrete parallel fractures. Water Resources Research 49, pp. 6105–6110.
S.K. Hansen (2011). On the effects of a totally reflecting barrier on an unbiased 1D random walk. Physica Status Solidi B 248(9), pp. 2112–2119.
S.K. Hansen and B.H. Kueper (2011). Forensic Misidentification of Aroclor Sources in Fractured Bedrock Due to "Chromatographic" Polychlorinated Biphenyl (PCB) Congener Separation. Environmental Forensics 12(1), pp. 2534.
S.K. Hansen and B.H. Kueper (2009). An efficient method for asymptotic solution to some linear PDEs having arbitrary timevarying type I boundary conditions. Applied Mathematics and Computation 207(1) pp. 273278.
S.K. Hansen and B.H. Kueper (2007). An analytical solution to multicomponent NAPL dissolution equations. Advances in Water Resources 30(3), pp. 382388.
R.K. Rowe, T. Mukunoki, R.J. Bathurst, S. Rimal, P. Hurst and S. Hansen (2007). Performance of a geocomposite liner for containing Jet A1 spill in an extreme environment. Geotextiles and Geomembranes 25(2), pp. 6877..