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Dive into the research topics where Robert S. Disselkamp is active.

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Featured researches published by Robert S. Disselkamp.


Review of Scientific Instruments | 2006

Design and operating characteristics of a transient kinetic analysis catalysis reactor system employing in situ transmission Fourier transform infrared

Yong Yang; Robert S. Disselkamp; Janos Szanyi; Charles H. F. Peden; Charles T. Campbell; J. G. Goodwin Jr.

A novel apparatus for gas phase heterogeneous catalysis kinetics is described. The apparatus enables fast isotopic transient kinetic analysis (ITKA) to be performed in which both the gaseous and adsorbed species inside the catalytic reactor are monitored simultaneously with rapid-scan transmission Fourier transform infrared (FTIR), and its gaseous effluent can be monitored by mass spectroscopy during rapid switching of reagent gas streams. This enables a more powerful version of the well-known steady-state isotopic transient kinetic analysis (SSITKA) technique in which the vibrational spectra of the gas phase and adsorbed species are also probed: FTIR-SSITKA. Unique reactor characteristics include tungsten construction, liquid nitrogen cooling or heating (∼200–770K), pressures of 1.0–2.5atm, fast reactor disassembly and reassembly, and catalyst loading in a common volume. The FTIR data acquisition rate of this apparatus (3Hz) is tenfold faster than previously reported instruments. A 95% signal decay time ...


Geophysical Research Letters | 1999

BrCl production in NaBr/NaCl/HNO3/O3 solutions representative of sea-salt aerosols in the marine boundary layer

Robert S. Disselkamp; Elaine G. Chapman; William R. Barchet; Steve D. Colson; Christian D. Howd

Atomic bromine and chlorine liberated from sea-salt aerosol is thought to play an important role in chemistry of the marine boundary layer. Despite numerous modeling studies, no prior experimental investigations of the oxidation of halide species contained in simulated, or actual, sea-salt solutions have been performed. We present laboratory data that examines chemistry in NaBr/NaCl/HNO 3 /O 3 solutions at 290 K. Ozonation experiments were performed by flowing ozone in air through a nitric acid/salt solution and monitoring pH with time using an ion-sensitive electrode. The rate of oxidation was observed to be first order in ozone concentration and to have a non-first order bromide concentration dependence. Ion chromatography was used to measure both bromide disappearance as well as oxidation products formed during the course of the reactions studied. Our measurements of the oxidation rate versus ion concentration indicate that the high ionic strength present in sea-salt aerosol will possess unique kinetics different from dilute solution behavior. In addition, our results are consistent with the reaction sequence O 3 + H + + Br - → O 2 + HOBr and HOBr + Cl - + H + → BrCl + H 2 O. These observations support the HOBr mediated Cl- oxidation process proposed previously (Vogt et al., 1996).


Atmospheric Environment | 2001

Aircraft observations of aerosols, O3 and NOy in a nighttime urban plume

Carl M. Berkowitz; Rahul A. Zaveri; Xindi Bian; Shiyuan Zhong; Robert S. Disselkamp; Nels S. Laulainen; Elaine G. Chapman

Abstract Nighttime measurements of aerosol surface area, O 3 , NO y and moisture were made downwind of Portland, Oregon, as part of a study to characterize the chemistry in a nocturnal urban plume. Air parcels sampled within the urban plume soon after sunset had positive correlations between O 3 , relative humidity, NO y and aerosol number density. However, the air parcels sampled within the urban plume just before dawn had O 3 mixing ratios that were highly anti-correlated with aerosol number density, NO y and relative humidity. Back-trajectories from a mesoscale model show that both the post-sunset and pre-dawn parcels came from a common maritime source to the northwest of Portland. The pre-dawn parcels with strong anti-correlations passed directly over Portland in contrast to the other parcels that were found to pass west of Portland. Several gas-phase mechanisms and a heterogeneous mechanism involving the loss of O 3 to the aerosol surface, are examined to explain the observed depletion in O 3 within the pre-dawn parcels that had passed over Portland.


Journal of Atmospheric Chemistry | 2001

A Temperature-Dependent Study of the Ozonolysis of Propene

Robert S. Disselkamp; Michel Dupuis

The ozonolysis of propene has been investigated in a temperature controlled reaction chamber at 295, 260, and 230 K. Experiments were performed using a total zero air pressure of 760 Torr (STP) and propene/ozone reactant mixing ratios ranging from 2.3 to 23 ppmv. An analysis of FTIR spectra collected at the conclusion of each reaction revealed that methane was formed with a yield of 0.14 ± 0.03 (precision) for all the temperatures investigated.In addition, the yield of HCHO decreased from 0.67 ± 0.04 to 0.43± 0.03 upon cooling from 295 to 230 K, whereas the yield of HCOOH increased from 0.11 ± 0.02 to 0.53 ± 0.04. Experiments were also performedusing an excess of cyclohexane (to scavenge OH) and it was found that the formaldehyde yield was 0.79 ± 0.05 and 0.61 ± 0.04 at 295 and260 K, respectively. Finally, to more fully understand the reaction energies involved in product formation, we have performed molecular orbital calculations of heats of formation of reactants, stable intermediates, and products. Three conclusions can be made of this work. First, the reaction CH2OO + Aldehyde → Secondary Ozonide → HCOOH + Aldehyde is not an important mechanism in formic acid production. Second, the decomposition of the primary ozonide products (e.g., C2 radical species) appears to occur, in part, by a thermal mechanism (e.g., thermalized to chamber temperature). Third, ab initio resultscombined with experiment reveal no correlation between reaction exothermicity and products formed (e.g., kinetically dictated product formation occurs). The abinitio database is provided nevertheless as a starting point for transition state calculations to be performed in the future. Finally, since formaldehyde yield decreases by at most ∼ 35% with decreasing temperature and formic acid is relatively unreactive in the atmosphere, our results suggest that temperature-dependent HCHO yield will constitute only a minor perturbation to HOx formation in the middle troposphere.


Journal of Physical Chemistry C | 2010

Non)formation of Methanol by Direct Hydrogenation of Formate on Copper Catalysts

Yong Yang; Charles A. Mims; Robert S. Disselkamp; Ja Hun Kwak; Charles H. F. Peden; Charles T. Campbell


Catalysis Letters | 2008

Isotope Effects in Methanol Synthesis and the Reactivity of Copper Formates on a Cu/SiO2 Catalyst

Yong Yang; Charles A. Mims; Robert S. Disselkamp; Donghai Mei; Ja Hun Kwak; Janos Szanyi; Charles H. F. Peden; Charles T. Campbell


Topics in Catalysis | 2009

Simultaneous MS-IR Studies of Surface Formate Reactivity Under Methanol Synthesis Conditions on Cu/SiO2

Yong Yang; Charles A. Mims; Robert S. Disselkamp; Charles H. F. Peden; Charles T. Campbell


Catalysis Today | 2006

Nitrogen release from a NOx storage and reduction catalyst

Russell G. Tonkyn; Robert S. Disselkamp; Charles H. F. Peden


Journal of Catalysis | 2004

A Comparison Between Conventional and Ultrasound-Mediated Heterogeneous Catalysis: Hydrogenation of 3-buten-1-ol Aqueous Solutions

Robert S. Disselkamp; Kayte M. Judd; Todd R. Hart; Charles H. F. Peden; Gerald J. Posakony; Leonard J. Bond


Journal of Atmospheric Chemistry | 2000

A Chamber Investigation of Nitric Acid-Soot Aerosol Chemistry at 298 K

Robert S. Disselkamp; Michael A. Carpenter; James P. Cowin

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Charles H. F. Peden

Pacific Northwest National Laboratory

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Todd R. Hart

Pacific Northwest National Laboratory

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Yong Yang

Pacific Northwest National Laboratory

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Russell G. Tonkyn

Pacific Northwest National Laboratory

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Benjamin D. Harris

Environmental Molecular Sciences Laboratory

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Donghai Mei

Pacific Northwest National Laboratory

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Elaine G. Chapman

Pacific Northwest National Laboratory

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James F. Kelly

Environmental Molecular Sciences Laboratory

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