AuthorRuskin, Helen Ann Kassander.
Arid regions agriculture -- Economic aspects -- Mathematical models.
Energy crops -- Economic aspects -- Mathematical models.
Energy crops -- Economic aspects -- Arizona -- Mathematical models.
Biomass energy industries -- Economic aspects -- Mathematical models.
Arid regions agriculture -- Economic aspects -- Arizona -- Mathematical models.
Biomass energy -- Economic aspects -- Arizona -- Mathematical models.
Committee ChairPingry, David
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractThe objective of this study is to develop a model to evaluate the economic feasibility of biofuels production, and in particular to isolate the variables crucial to feasibility. The model constructed to define these variables is unique in its ability to accommodate a variety of plants and to integrate all portions of the production process; it was tested on a case study of a Euphorbia lathyris industry. The model minimizes costs of production to determine the best configuration for the industry. Total cost equals the sum of costs incurred in each segment of the process: growth, harvest, transport, and extraction. The solution is determined through a non-linear transportation- transshipment algorithm which describes production as a series of nodes and links. Specific application of the model was analysis of E. lathyris biofuel production in Arizona. Simulations were run examining the sensitivity of biocrude cost to changes in input parameters. Conclusions are summarized as follows. * No change in any single element can reduce final cost sufficiently to enable competitive production in the near future. * The major factor necessary to bring cost into range is improvement in biological yield. Two components of equal importance are tonnage produced per acre and percentage extractables recovered in processing. * Lowering cropping costs provided the most effective improvements of economic inputs. Perennial crops significantly reduced farm costs. * Transportation costs outweighed economies of scale in extraction; extractor location close to crops is more efficient than centralized. The cost minimization model was successfully used to isolate the critical factors for an E. lathyris industry in an arid region. Results determine that this industry would not be competitive in Arizona without dramatic improvements in yields and moderate changes in a combination of input costs. Viability is critically dependent on improvements in tonnage yield produced per acre and percent extractables recovered.
Degree NamePh. D.
Degree ProgramArid Lands Resource Sciences
Degree GrantorUniversity of Arizona
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A digital model for the transport of trichloroethylene in an alluvial aquifer, Tucson, ArizonaCross, Mark Manthei.; Simpson, Eugene S. (The University of Arizona., 1983)Concentrations of trichloroethylene (TCE) have been detected in groundwater from wells in several areas south of Tucson, Arizona. A two-dimensional finite difference model was compiled from hydrogeologic data for an area of about 55 square miles, and was calibrated to reproduce historical water level data and compute seepage velocities for the period 1952 to 1980. The model uses the method of characteristics to solve the advection-dispersion equation. Contaminant sources were imposed at a group of TCE disposal sites at an industrial facility. Changes in concentration in the upper zone of the regional aquifer were simulated for the period 1952 to 1982. The model successfully reproduces TCE concentrations measured in groundwater from the upper zone in the area of the facility and northwest of the facility. Results for 1982 indicate that the 10 ppb contour of TCE concentration extended about 4,000 feet to the northwest of the facility.