An understanding of the ignition and oxidation characteristics of propanol, as well as other alcohols, is important toward the development and design of combustion engines that can effectively utilize bioderived and bioblended fuels. Building upon a database for “first-generation” alcohols including methanol and ethanol, the ignition characteristics of the two isomers of propanol (n-propanol and iso-propanol) have been studied in a shock tube. Ignition delay times for propanol/oxygen/argon mixtures have been measured behind reflected shock waves at temperatures ranging from approximately 1350 to 2000 K and a pressure of 1 atm. Equivalence ratios of 0.5, 1.0, and 2.0 have been used. Pressure measurements and CH* emissions were used to determine ignition delay times. The influences of equivalence ratio, temperature, and mixture strength on ignition delay have been characterized and compared to the behavior seen with a newly developed detailed kinetic mechanism. The overall trends are captured fairly well by the mechanism, which include a greater level of reactivity for the n-propanol mixtures relative to iso-propanol at the conditions used in this study.

An improved global positioning system (GPS)-based animal tracking system is needed to meet quickly evolving demands of ecological research, range livestock production, and natural resource management. Commercially available tracking systems lack the data storage capacity needed to frequently collect animal location data (e.g., 15-minute intervals or less) over long-term deployment periods (e.g., 1 year or more). Some commercial systems have remote data-download capabilities, reducing the need to recapture tagged animals for data retrieval, but these systems download data via satellite (Argos), global system for mobile communications (GSM) cellular telephone, or telemetry radio frequencies. Satellite systems are excessively expensive, and GSM cellular coverage is extremely limited within the United States. Radio-based systems use narrow-band very-high-or ultra-high frequencies requiring the user to obtain frequency allocations. None of these existing systems were designed to provide continual, real-time data access. The Clark GPS Animal Tracking System (Clark ATS) was developed to meet the evolving demands of animal ethologists, ecologists, natural resource managers, and livestock producers. The Clark ATS uses memory-card technology for expandable data storage from 16 megabytes to 8 gigabytes. Remote data downloading and program uploading is accomplished using spread-spectrum radio transceivers, which do not require narrow-band radio frequency allocations. These radios also transmit, at a user-defined time interval, a real-time, GPS-location beacon to any Clark ATS base station within range (about 24 km or 15 miles line of sight). Advances incorporated into the Clark ATS make it possible to evaluate animal behavior at very fine spatial-and temporal-resolution over long periods of time. The real-time monitoring provided by this system enables researchers to accurately examine animal distribution and activity responses to acute, short-term disturbances relative to longerterm behavioral patterns. The Clark ATS also provides a huge time-and cost-savings to researchers and natural resource managers attempting to relocate a tagged animal in the field for direct observation or other operations.

This study investigates the autoignition behavior of two gasoline surrogates doped with an alkyl nitrate cetane enhancer, 2-ethy-hexyl nitrate (2EHN) to better understand dopant interactions with the fuels, including influences of accelerating kinetic pathways and enhanced exothermicity. A primary reference fuel (PRF) blend of n-heptane/iso-octane, and a toluene reference fuel (TRF) blend of n-heptane/iso-octane/toluene are used where the aromatic fraction of the latter is set to 20% (liquid volume), while the content of n-heptane is adjusted so that the overall reactivity of the undoped fuels is similar, e.g., Anti-Knock Index (AKI) of ~91, Cetane Number (CN) ~25. Doping levels of 0.1, 1.0 and 3.0% (liquid volume basis) are used where tests are conducted within a rapid compression machine (RCM) at a compressed pressure of 21 bar, covering temperatures from 675 to 1025 K with stoichiometric fuel-oxygen ratios at O 2 = 11.4%.At the experimental conditions, it is found that the doping effectiveness of 2EHN is fairly similar between the two fuels, though 2EHN is more effective in the aromatic blend at the lowest temperatures, while it is slightly more effective in the non-aromatic blend at intermediate temperatures. Kinetic modeling of the experiments indicates that although some of the reactivity trends can be captured using a detailed model, the extents of predicted Cetane Number enhancement by 2EHN are too large, while differences in fuel interactions for the two fuels results in excessive stimulation of the non-aromatic blend. Sensitivity analysis using the kinetic model indicates that the CH 2 O and CH 3 O 2 chemistry are very sensitive to the dopant at all conditions. The rate of 2EHN decomposition is only important at low temperatures where its decomposition rate is slow due to the high activation energy of the reaction. At higher temperatures, dopant-derived 3-heptyl radicals are predicted to play an important role stimulating ignition. Finally, nitrogen chemistry becomes important only at the highest doping levels, primarily through the formation of methyl and ethyl nitrite, and nitric acid.

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