Abstract. Direct quantification of fossil fuel CO 2 (CO 2 ff) in atmospheric samples can be used to examine several carbon cycle and air quality questions. We collected in situ CO 2 , CO, and CH 4 measurements and flask samples in the boundary layer and free troposphere over Sacramento, California, USA, during two aircraft flights over and downwind of this urban area during spring of 2009. The flask samples were analyzed for 14 CO 2 and CO 2 to determine the recently added CO 2 ff mole fraction. A suite of greenhouse and other trace gases, including hydrocarbons and halocarbons, were measured in the same samples. Strong correlations were observed between CO 2 ff and numerous trace gases associated with urban emissions. From these correlations we estimate emission ratios between CO 2 ff and these species, and compare these with bottom-up inventory-derived estimates. Recent county level inventory estimates for carbon monoxide (CO) and benzene from the California Air Resources Board CEPAM database are in good agreement with our measured emission ratios, whereas older emissions inventories appear to overestimate emissions of these gases by a factor of two. For most other trace species, there are Correspondence to: J. C. Turnbull (jocelyn.turnbull@noaa.gov) substantial differences (200-500%) between our measured emission ratios and those derived from available emission inventories. For the first flight, we combine in situ CO measurements with the measured CO:CO 2 ff emission ratio of 14 ± 2 ppbCO/ppmCO 2 to derive an estimate of CO 2 ff mole fraction throughout this flight, and also estimate the biospheric CO 2 mixing ratio (CO 2 bio) from the difference of total and fossil CO 2 . The resulting CO 2 bio varies dramatically from up to 8 ± 2 ppm in the urban plume to −6 ± 1 ppm in the surrounding boundary layer air. Finally, we use the in situ estimates of CO 2 ff mole fraction to infer total fossil fuel CO 2 emissions from the Sacramento region, using a mass balance approach. The resulting emissions are uncertain to within a factor of two due to uncertainties in wind speed and boundary layer height. Nevertheless, this first attempt to estimate urban-scale CO 2 ff from atmospheric radiocarbon measurements shows that CO 2 ff can be used to verify and improve emission inventories for many poorly known anthropogenic species, separate biospheric CO 2 , and indicates the potential to constrain CO 2 ff emissions if transport uncertainties are reduced.
= dimensionless axial position o = frequency, rad./hr. 8 = time, hr. Su b r r i p t s g = gas phase in = gas phase inlet k 1 = liquid phase Coefficienh in Gas Phase Equations (17), (18). (191, and (23) 1 2 0 n ma = radial mesh point location = axial mesh point location A. -----2 0The hydrogenation of alpha-methylstyrene to cumene at 20 to 50°C. was studied experimentally with o trickle-bed reactor comprising a single vertical column of spherical porous palladium-on-alumina catalyst pellets. Other studies with powdered catalyst and studies in which catalyst pellets were swirled in a reactor allowed the intrinsic kinetics and effectiveness factor of the catalyst pellets to be determined. A t 50°C. the reaction rate in the trickle-bed was about one-half of that in the absence of mass transfer limitations in the outside liquid film. The effectiveness factor of the pellets alone at 50°C. was 0.0057, and the tortuosity factor was 7.5. Experimental results are compared with four theoreticol models for tricklebed reactors and criteria are presented for estimating whether mass transfer through the outside film is a significant resistance in an industrial trickle-bed reactor.A trickle-bed reactor consists of a fixed catalyst bed in the bulk gas phase and the liquid-gas interface, ( b ) mass which the liquid reactant flows over the catalyst pellets transfer through the liquid film surrounding the pellets, while the reacting gas, which fills the voids, flows either (c) diffusion and simultaneous reaction within the liquidin the same or opposite direction. The rate-controlling step filled catalyst pores, and ( d ) intrinsic kinetics of reaction can be one or a combination of the following processes: at the catalyst surface. The object of this study was to (a) mass transfer of reactants and/or products between determine the role played in the performance of a trickle-
Data are presented on the flow of air at low pressures in copper pipes of radius 0.795 and 1.30 cm; iron pipes of radius 2.64, 5.12, and 10.1 cm; and for hydrogen in a copper pipe of radius 1.30 cm. Data are also given for the resistance to flow of air in 1½- and 3-inch nominal pipe size elbows, for 1½-inch Kinney bellows valves, and for short sections of 1-inch nominal pipe size iron pipe connecting large gas chambers. The data on straight iron and copper pipes, together with the data from the literature on glass capillaries, are correlated by the introduction of a correction factor F in Poiseuille's equation. F is correlated graphically in terms of a dimensionless group representing the ratio of mean free path to pipe radius, with separate curves for iron pipe and for copper and glass pipes or capillaries.
Suspensions of human red cells in citrated plasma, in Ringer solution, and in Ringer solution containing albumin were passed through straight and curved glass and plastic hollow fibers (diameter range, 100–1,000 μ). Pressure-flow relations were measured over the pressure range of 0.1– 800 mm water, corresponding to a shear stress range of 0.01– 80 dynes/cm2. The suspensions were tested simultaneously in a rotational viscometer. It was found that red cell suspensions exhibit a yield shear stress only if the plasma protein fibrinogen is present. Experimental pressure-flow data in hollow fibers were in excellent agreement with rotational viscometer measurements and with analytical predictions based on the assumptions that blood flows as a homogeneous continuum and that the velocity at the wall is zero. Effects of tube surface characteristics and curvature on the pressure drop-flow rate relation were not discernible. microcirculation models; model blood flow; yield stress of blood; capillary blood flow and viscometry; fibrinogen and blood flow in hollow fibers; non-Newtonian flow of blood in hollow fibers Submitted on July 20, 1964
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.