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A Numerical Investigation into the Anomalous Slight NOx Increase when Burning Biodiesel: A New (Old) Theory

Description: Biodiesel is a notable alternative to petroleum derived diesel fuel because it comes from natural domestic sources and thus reduces dependence on diminishing petroleum fuel from foreign sources, it likely lowers lifecycle greenhouse gas emissions, and it lowers an engine's emission of most pollutants as compared to petroleum derived diesel. However, the use of biodiesel often slightly increases a diesel engine's emission of smog forming nitrogen oxides (NO{sub x}) relative to petroleum diesel. … more
Date: January 30, 2007
Creator: Ban-Weiss, G. A.; Chen, J. Y.; Buchholz, B. A. & Dibble, R. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Kinetics of Beta-14[14C] Carotene in a Human Subject Using Accelerator Mass Spectrometry

Description: {beta}-Carotene is a tetraterpenoid distributed widely throughout the plant kingdom. It is a member of a group of pigments referred to as carotenoids that have the distinction of serving as metabolic precursors to vitamin A in humans and many animals [1,2]. We used Accelerator Mass Spectrometry (AMS) [3] to determine the metabolic behavior of a physiologic oral dose of {beta}-[{sup 14}C]carotene (200 nanoCuries; 0.57 {micro}mol) in a healthy human subject. Serial blood specimens were collected … more
Date: January 31, 2000
Creator: Dueker, S. R.; Lin, Y.; Follett, J. R.; Clifford, A. J. & Buchholz, B. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Quantifying the Contribution of Lubrication Oil Carbon to Particulate Emissions from a Diesel Engine

Description: The contribution of lubrication oil to particulate matter (PM) emissions from a Cummins B5.9 Diesel engine was measured using accelerator mass spectrometry to trace carbon isotope concentrations. The engine operated at fixed medium load (285 N-m (210 ft.lbs.) at 1600 rpm) used 100% biodiesel fuel (8100) with a contemporary carbon-14 ({sup 14}C) concentration of 103 amol {sup 14}C mg C. The {sup 14}C concentration of the exhaust CO{sub 2} and PM were 102 and 99 amol {sup 14}C/mg C, respectively.… more
Date: January 31, 2003
Creator: Buchholz, B. A.; Dibble, R. W.; Rich, D. & Cheng, A. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Using Carbon-14 Isotope Tracing to Investigate Molecular Structure Effects of the Oxygenate Dibutyl Maleate on Soot Emissions from a DI Diesel Engine

Description: The effect of oxygenate molecular structure on soot emissions from a DI diesel engine was examined using carbon-14 ({sup 14}C) isotope tracing. Carbon atoms in three distinct chemical structures within the diesel oxygenate dibutyl maleate (DBM) were labeled with {sup 14}C. The {sup 14}C from the labeled DBM was then detected in engine-out particulate matter (PM), in-cylinder deposits, and CO{sub 2} emissions using accelerator mass spectrometry (AMS). The results indicate that molecular structur… more
Date: January 7, 2004
Creator: Buchholz, B. A.; Mueller, C. J.; Upatnieks, A.; Martin, G. C.; Pitz, W. J. & Westbrook, C. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Investigation of HCCI Combustion of Diethyl Ether and Ethanol Mixtures Using Carbon 14 Tracing and Numerical Simulations

Description: Despite the rapid combustion typically experienced in Homogeneous Charge Compression Ignition (HCCI), components in fuel mixtures do not ignite in unison or burn equally. In our experiments and modeling of blends of diethyl ether (DEE) and ethanol (EtOH), the DEE led combustion and proceeded further toward completion, as indicated by {sup 14}C isotope tracing. A numerical model of HCCI combustion of DEE and EtOH mixtures supports the isotopic findings. Although both approaches lacked informatio… more
Date: January 16, 2004
Creator: Mack, J. H.; Dibble, R. W.; Buchholz, B. A. & Flowers, D. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Human Vitamin B12 Absorption and Metabolism are Measured by Accelerator Mass Spectrometry Using Specifically Labeled 14C-Cobalamin

Description: There is need for an improved test of human ability to assimilate dietary vitamin B{sub 12}. Assaying and understanding absorption and uptake of B{sub 12} is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry (AMS) is uniquely suited for assessing absorption and kinetics of {sup 14}C-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of carbon-14 ({sup 14}C) in microliter … more
Date: January 26, 2006
Creator: Carkeet, C.; Dueker, S. R.; Lango, J.; Buchholz, B. A.; Miller, J. W.; Green, R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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