1,129 research outputs found
Integrated embedding optimization applied to Salt Lake Valley aquifers
The embedding optimization modeling approach is adapted to aid sustainable groundwater quantity and quality management of complex nonlinear multilayer aquifers. Implicit block-centered finite difference approximations of the quasi three-dimensional unsteady flow equation and Galerkin finite element approximations of the two-dimensional advection-dispersion transport equation are embedded directly as constraints in the model. Also used are nonlinear constraints describing river-aquifer interflow, evapotranspiration, and vertical flow reduction due to unconfinement. These circumvent use of large numbers of integer variables. The use of both linear and nonlinear formulations in a cyclical manner reduces execution time and improves confidence in solution optimality. The methodology is demonstrated for Salt Lake valley where groundwater quantity and quality management are needed, the proportion of pumping cells and cells needing head constraint is large, and many flows are described by discrete nonlinear or piece wise linear functions
Modelling for potentiometric surface management of multilayer aquifer systems
Assuring the long-term availability of groundwater of adequate quality and quantity frequently requires the implementation of appropriate ground-water and conjunctive water management strategies. Presented is a model for developing optimal strategies for an multilayer aquifer in which stream-aquifer interflow is affected by the potentiometric surface and ground-water use. The model is applied to the Salt Lake Valley. Discussed is the use of pumping to control: l) potential migration of non-point source agricultural contaminants between aquifer layers and 2) the movement of a mile-long plume caused by mining waste
Elastocapillary driven assembly of particles at free-standing smectic-A films
Colloidal particles at complex fluid interfaces and within films assemble to
form ordered structures with high degrees of symmetry via interactions that
include capillarity, elasticity, and other fields like electrostatic charge.
Here we study microparticle interactions within free-standing smectic-A films,
in which the elasticity arising from the director field distortion and
capillary interactions arising from interface deformation compete to direct the
assembly of motile particles. New colloidal assemblies and patterns, ranging
from 1D chains to 2D aggregates, sensitive to the initial wetting conditions of
particles at the smectic film, are reported. This work paves the way to
exploiting LC interfaces as a means to direct spontaneously formed,
reconfigurable, and optically active materials.Comment: 8 pages, 6 figures. Supplementary Materials: 3 pages, 3 figure
Characterizing non-deterministic noiseless linear amplifiers at the quantum limit
We address the characterization of the gain parameter of a non-deterministic
noiseless linear amplifier (NLA) and compare the performances of different
estimation strategies using tools from quantum estimation theory. At first, we
show that, contrary to naive expectations, post-selecting only the amplified
states does not offer the most accurate estimate. We then focus on minimal
implementations of a NLA, i.e. those obtained by coupling the input state to a
two-level system, and show that the maximal amount of information about the
gain of the NLA is obtained by measuring the whole composite system. The
quantum Fisher information (QFI) of this best-case scenario is analysed in some
details, and compared to the QFI of the post-selected states, both for
successful and unsuccessful amplification. Eventually, we show that full
extraction of the available information is achieved when the non-deterministic
process is implemented by a L\"uders instrument. We also analyse the precision
attainable by probing NLAs by single-mode pure states and measuring the field
or the number of quanta, and discuss in some details the specific cases of
squeezed vacuum and coherent states.Comment: 20 pages, 5 figure
- …