Iain McCreary - Academia.edu (original) (raw)
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Papers by Iain McCreary
... Preliminary experiments with crystal violet used as a test absorber have demonstrated detecti... more ... Preliminary experiments with crystal violet used as a test absorber have demonstrated detection sensitivity of 10 parts per trillion (ppt). Country of Publication, United States. Language, English. Format, Medium: P; Size: 8 p. Availability, OSTI; NTIS; GPO Dep. ...
A new technique for the detection of trace concentrations of molecules in solution has been devel... more A new technique for the detection of trace concentrations of molecules in solution has been developed. This system utilizes the amplification characteristics of a bubble chamber in which energy deposition from laser absorption is monitored. In the experimental set-up, a trace quantity of solute is introduced into liquid propane that is contained in a small (10 ml) stainless steel cell at 120 psi. The propane is superheated by sudden reduction of the cell pressure. Before wall nucleated boiling occurs, target solute molecules are energized by a laser pulse. Absorption of pump laser energy results in the formation of nucleation centers which develop into bubbles and which in turn are detected by CCD camera. Preliminary experiments with crystal violet used as a test absorber have demonstrated detection sensitivity of 10 parts per trillion (ppt).
Journal of Atmospheric Chemistry, 1997
Local surface travel needs in the People‘s Republic of China (mainlandChina) have traditionally b... more Local surface travel needs in the People‘s Republic of China (mainlandChina) have traditionally been met largely by nonpolluting bicycles. A majorautomobile manufacturing/importing effort has begun in the country over thelast decade, and planning documents indicate that the Chinese may strive toacquire more than 100 million vehicles early in the next century. By analogywith large automotive fleets already existing in the western world, bothregional and global scale pollution effects are to be expected from theincrease. The present work adopts the latest projections of Chinese automobilemanufacture and performs some quantitative assessments of the extent ofpollution generation.Focus for the investigation is placed upon the oxidant ozone. Emissions of theprecursor species nitrogen oxides and volatile organics are constructed basedon data for the current automotive sector in the eastern portion of the UnitedStates. Ozone production is first estimated from measured values forcontinental/oceanic scale yields relative to precursor oxidation. Theestimates are then corroborated through idealized two dimensional modeling ofthe photochemistry taking place in springtime air flow off the Asian land massand toward the Pacific Ocean. The projected fleet sizes could increase coastaland remote oceanic ozone concentrations by tens of parts per billion (ppb)in the lower troposphere. Influences on the tropospheric aerosol system andon the major greenhouse gas carbon dioxide are treated peripherally. Nitrogenoxides created during the vehicular internal combustion process willcontribute to nitrate pollution levels measured in the open Pacific. Thepotential for soot and fugitive dust increases should be considered as theautomotive infrastructure develops. Since the emerging Chinese automotivetransportation system will represent a substantial addition to the globalfleet and all the carbon in gasoline is eventually oxidized completely, asignificant rise in global carbon dioxide inputs will ensue as well.Some policy issues are treated preliminary. The assumption is made thatalterations to regional oxidant/aerosol systems and to terrestrial climate areconceivable. The likelihood that the Chinese can achieve the latest vehiclefleet goals is discussed, from the points of view of new production, positivepollution feedbacks from a growing automobile industry, and known petroleumreserves. Vehicular fuel and maintenance options lying before the Chinese areoutlines and compared. To provide some perspective on the magnitude of theenvironmental changes associated with an Asian automotive buildup, recentestimates of the effects of future air traffic over the Pacific Rim aredescribed.
Geophysical Research Letters, 1997
... Preliminary experiments with crystal violet used as a test absorber have demonstrated detecti... more ... Preliminary experiments with crystal violet used as a test absorber have demonstrated detection sensitivity of 10 parts per trillion (ppt). Country of Publication, United States. Language, English. Format, Medium: P; Size: 8 p. Availability, OSTI; NTIS; GPO Dep. ...
A new technique for the detection of trace concentrations of molecules in solution has been devel... more A new technique for the detection of trace concentrations of molecules in solution has been developed. This system utilizes the amplification characteristics of a bubble chamber in which energy deposition from laser absorption is monitored. In the experimental set-up, a trace quantity of solute is introduced into liquid propane that is contained in a small (10 ml) stainless steel cell at 120 psi. The propane is superheated by sudden reduction of the cell pressure. Before wall nucleated boiling occurs, target solute molecules are energized by a laser pulse. Absorption of pump laser energy results in the formation of nucleation centers which develop into bubbles and which in turn are detected by CCD camera. Preliminary experiments with crystal violet used as a test absorber have demonstrated detection sensitivity of 10 parts per trillion (ppt).
Journal of Atmospheric Chemistry, 1997
Local surface travel needs in the People‘s Republic of China (mainlandChina) have traditionally b... more Local surface travel needs in the People‘s Republic of China (mainlandChina) have traditionally been met largely by nonpolluting bicycles. A majorautomobile manufacturing/importing effort has begun in the country over thelast decade, and planning documents indicate that the Chinese may strive toacquire more than 100 million vehicles early in the next century. By analogywith large automotive fleets already existing in the western world, bothregional and global scale pollution effects are to be expected from theincrease. The present work adopts the latest projections of Chinese automobilemanufacture and performs some quantitative assessments of the extent ofpollution generation.Focus for the investigation is placed upon the oxidant ozone. Emissions of theprecursor species nitrogen oxides and volatile organics are constructed basedon data for the current automotive sector in the eastern portion of the UnitedStates. Ozone production is first estimated from measured values forcontinental/oceanic scale yields relative to precursor oxidation. Theestimates are then corroborated through idealized two dimensional modeling ofthe photochemistry taking place in springtime air flow off the Asian land massand toward the Pacific Ocean. The projected fleet sizes could increase coastaland remote oceanic ozone concentrations by tens of parts per billion (ppb)in the lower troposphere. Influences on the tropospheric aerosol system andon the major greenhouse gas carbon dioxide are treated peripherally. Nitrogenoxides created during the vehicular internal combustion process willcontribute to nitrate pollution levels measured in the open Pacific. Thepotential for soot and fugitive dust increases should be considered as theautomotive infrastructure develops. Since the emerging Chinese automotivetransportation system will represent a substantial addition to the globalfleet and all the carbon in gasoline is eventually oxidized completely, asignificant rise in global carbon dioxide inputs will ensue as well.Some policy issues are treated preliminary. The assumption is made thatalterations to regional oxidant/aerosol systems and to terrestrial climate areconceivable. The likelihood that the Chinese can achieve the latest vehiclefleet goals is discussed, from the points of view of new production, positivepollution feedbacks from a growing automobile industry, and known petroleumreserves. Vehicular fuel and maintenance options lying before the Chinese areoutlines and compared. To provide some perspective on the magnitude of theenvironmental changes associated with an Asian automotive buildup, recentestimates of the effects of future air traffic over the Pacific Rim aredescribed.
Geophysical Research Letters, 1997