http://hdl.handle.net/1957/16184 2013-05-23T15:31:40Z http://hdl.handle.net/1957/38713 Microwave Extraction of Essential Oil from Peppermint - Field Trial Hackleman, David; Smith, Connor J.; Lebsack, Jonathan An in-field test of the solvent free microwave extraction of peppermint oil was held in mid-August 2009 at Butler Valley Farms in Stayton, Oregon. Results of the trial were limited due to rapid coalescence of the mint oil prior to entry into the separator. This resulted in no mint oil actually received at the normal receiving site. A small quantity of mint oil was discovered during take-down and laboratory analysis indicates it to be pure. For the Solvent Free Microwave Extraction (SFME) system to work effectively in the large scale (farm operation) condition, it is believed that a significant change in the condensation apparatus will be necessary. Work demonstrating a solution to that issue will be presented. The 100KW 915MHz microwave unit (normally used for drying) performed well in the farm environment and after significant modifications, feed systems were developed to take chopped mint hay from existing mint tubs and move it into the extractor. The results of this field trial were adequate to enable design improvements for future development. This is an author's manuscript. This paper was presented at the 2nd Global Congress on Microwave Energy Applications (2GCMEA). July 23-27, 2012. Hilton Long Beach. Long Beach, CA. USA Session D6.6. 2012-07-27T00:00:00Z http://hdl.handle.net/1957/38293 Horticultural Applications of a Newly Revised USDA Plant Hardiness Zone Map Widrlechner, Mark P.; Daly, Christopher; Keller, Markus; Kaplan, Kim The accurate prediction of winter injury caused by low-temperature events is a key component of the effective cultivation of woody and herbaceous perennial plants. A common method employed to visualize geographic patterns in the severity of low-temperature events is to map a climatological variable that closely correlates with plant survival. The U.S. Department of Agriculture Plant Hardiness Zone Map (PHZM) is constructed for that purpose. We present a short history of PHZM development, culminating in the recent production of a new, high-resolution version of the PHZM, and discuss how such maps relate to winterhardiness per se and to other climatic factors that affect hardiness. The new PHZM is based on extreme minimum-temperature data logged annually from 1976 to 2005 at 7983 weather stations in the United States, Puerto Rico, and adjacent regions in Canada and Mexico. The PHZM is accessible via an interactive website, which facilitates a wide range of horticultural applications. For example, we highlight how the PHZM can be used as a tool for site evaluation for vineyards in the Pacific northwestern United States and as a data layer in conjunction with moisture-balance data to predict the survival of Yugoslavian woody plants in South Dakota. In addition, the new map includes a zip code finder, and we describe how it may be used by governmental agencies for risk management and development of recommended plant lists, by horticultural firms to schedule plant shipments, and by other commercial interests that market products seasonally. This is a scanned version of a published article. The original can be found at: http://horttech.ashspublications.org/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. 2012-02-01T00:00:00Z http://hdl.handle.net/1957/37824 Correspondence between one- and two-equation models for solute transport in two-region heterogeneous porous media Davit, Y.; Wood, B. D.; Debenest, G.; Quintard, M. Abstract In this work, we study the transient behavior of homogenized models for solute transport in two-region porous media. We focus on the following three models: (1) a time nonlocal, two-equation model (2eq-nlt). This model does not rely on time constraints and, therefore, is particularly useful in the short-time regime, when the time scale of interest (t) is smaller than the characteristic time (τ₁) for the relaxation of the effective macroscale parameters (i.e., when t ≤ τ₁); (2) a time local, two-equation model (2eq). This model can be adopted when (t) is significantly larger than (τ₁) (i.e., when t ≫ τ₁); and (3) a one-equation, time-asymptotic formulation (1eq∞). This model can be adopted when (t) is significantly larger than the time scale (τ₂) associated with exchange processes between the two regions (i.e., when t ≫ τ₂). In order to obtain insight into this transient behavior, we combine a theoretical approach based on the analysis of spatial moments with numerical and analytical results in several simple cases. The main result of this paper is to show that there is only a weak asymptotic convergence of the solution of (2eq) towards the solution of (1eq∞) in terms of standardized moments but, interestingly, not in terms of centered moments. The physical interpretation of this result is that deviations from the Fickian situation persist in the limit of long times but that the spreading of the solute is eventually dominating these higher order effects. This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/11242. 2012-10-01T00:00:00Z http://hdl.handle.net/1957/37458 Investigating the pore-scale mechanisms of microbial enhanced oil recovery Armstrong, Ryan T.; Wildenschild, Dorthe Microbial Enhanced Oil Recovery (MEOR) is a process where microorganisms are used for tertiary oil recovery. Numerous mechanisms have been proposed in the literature through which microorganisms facilitate the mobilization of residual oil. Herein, we focus on the MEOR mechanisms of interfacial tension reduction (via biosurfactant) and bioclogging in water-wet micromodels, using Shewanella oneidensis (MR-1) that causes bioclogging and Bacillus mojavensis (JF-2) that produces biosurfactant and causes bioclogging. Micromodels were flooded with an assortment of flooding solutions ranging from metabolically active bacteria to nutrient limited bacteria to dead inactive biomass to asses the effectiveness of the proposed MEOR mechanisms of bioclogging and biosurfactant production. Results indicate tertiary flooding of the micromodel system with biomass and biosurfactant was optimal for oil recovery due to the combined effects of bioclogging of the pore-space and interfacial tension reduction. However, biosurfactant was able to recover oil in some cases dependent on wettability. Biomass without biosurfactant that clogged the pore-space also successfully produced additional oil recovery. When analyzing residual oil blob morphology, MEOR resulted in oil blob size and radius of curvature distributions similar to those obtained by an abiotic capillary desaturation test, where flooding rate was increased post secondary recovery. Furthermore, for the capillary number calculated during MEOR flooding with bioclogging and biosurfactant, lower residual oil saturation was measured than for the corresponding capillary number under abiotic conditions. These results suggest that bioclogging and biosurfactant MEOR is a potentially effective approach for pore morphology modification and thus flow alteration in porous media that can have a significant effect on oil recovery beyond that predicted by capillary number. This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/journal-of-petroleum-science-and-engineering/. 2012-09-01T00:00:00Z