A Stochastic Model for Planning Swine
Facilities
Lluis M. Plà-Aragonés (University of Lleida)
Abstract:
A simulation model and its application for planning
swine facilities are presented. Swine production is becoming more and more
specialized, hence the sizing of a farm producing piglets is the main
strategic decision concerning farmers who invest in sow production, since a
farm comprises a big range of facilities with many possible sizes. The
classical approach is deterministic, including sometimes some security margins
without considering variations in future sow performance or in the management
policy. The stochastic model presented here has revealed practical differences
with respect to deterministic approaches. As result, simulation is useful to
determine accurately the capacity, improve farm design, prevent practical
problems and fit housing cost. Furthermore, the implementation in Extend
allows potential users to perform efficiently different kinds of analyses.
Simulating Uncertainty in Mass Balance Modeling for
Fresh Water Reservoirs. Case Study: Deer Creek Reservoir, Utah,
U.S.A.
Ahmad M. Salah, Paul J. Fields, and A. Woodruff Miller
(Brigham Young University)
Abstract:
Simple mass balance techniques can be used to build a
zero-dimensional model for a fresh water reservoir to quantify the amount of
water and certain pollutants flowing into and out of the system. Yet, great
uncertainty is involved in the environmental and hydrological factors related
to a reservoir and it is useful to build a model that incorporates
uncertainty. A generic mass balance model was built for a hypothetical
reservoir and applied to Deer Creek Reservoir in Utah. Simulation was used to
model the stochastic nature of the inflows and outflows to estimate the
distribution of water volume and pollutant concentrations. The historical
observations and simulated values were shown to be in good agreement. The
model can therefore be used to manage the performance of the reservoir. The
modeling process is not site specific, thus it can be used to model any
reservoir provided that there are enough data.
Numerical Simulation of Dyebath and the Influence of
Dispersion Factor on Dye Transport
Renzo Shamey (North Carolina
State University) and Xiaoming Zhao and Roger H. Wardman (Heriot-Watt
University)
Abstract:
In order to model the mass transfer in a fluid, a
“dispersion” model is frequently used. When the flow behavior does not
drastically deviate from plug flow, the model performs well. The dispersive
flow properties of liquids within fibrous textile assemblies however, have not
been fully explored. In the mass transfer model, the dispersive flow is
assumed to reduce the concentration gradient of dye liquor flowing through the
package. This paper illustrates the influence of dispersion term on dye
transport based on numerical simulation of dyebath. The transfer of dye
through the package is described by a set of time-dependent partial
differential equations, which govern convection, dispersion, and adsorption of
dyes in the dyebath and across the yarn package. The simulation results prove,
theoretically, that the inclusion of the dispersion term in the dyeing model
improves the results of the dyeing process in terms of dye uptake and
levelness.
