Kohoutek, photometric photography experiment (S233)

The final results of the Skylab 4 experiment S233, Kohoutek photometric photography experiment, which undertook a series of visible light photographs suitable for photometry and for a photographic history of Comet Kohoutek are described. The experiment concept, the data reduction method, and the results obtained are discussed

Claim your online scholarly presence: ORCiD

Presented as a Small Group/Roundtable Discussion at 2020 IUSM Education Day.Claiming, maintaining, and tracking research output is crucial to a researcher’s continued visibility and impact. Tracking scholarly output and cultivating information about a researcher's work is made possible with online scholarly profile tools. As the most widely accepted unique identifier for authors, ORCiD IDs are increasingly required for: paper submissions to journals, grant submissions, and various NIH research training and career development awards. Attendees participated in hands on activities to set up profiles, and discover more information about tracking their impact going forward, and utilize existing connections between different scholarly profile tools. Learning objectives: • List reasons why maintaining scholarly profiles is important to researchers • Describe the benefits of several scholarly profile tools • Set up and/or update your scholarly profile(s

Multi-filter spectrophotometry of quasar environments

A many-filter photometric technique for determining redshifts and morphological types, by fitting spectral templates to spectral energy distributions, has good potential for application in surveys. Despite success in studies performed on simulated data, the results have not been fully reliable when applied to real, low signal-to-noise data. We are investigating techniques to improve the fitting process

A preliminary quarantine analysis of a possible Mariner Venus 1972 mission

Spacecraft contamination preliminary quarantine analysis for possible 1972 Mariner Venus prob

Optical measurement of multiplume interaction Interim report

Exhaust flowfield data from scale model tests for determining configurations of multinozzle rocket engines operating at high altitud

Optical measurement of multiplume interaction Final report

Laser velocimeter tests in supersonic tunnels and flowfield characteristics in base flow region of Saturn 2 type clustered nozzle configuratio

Chemical aging of m-xylene secondary organic aerosol: laboratory chamber study

Secondary organic aerosol (SOA) can reside in the atmosphere for a week or more. While its initial formation from the gas-phase oxidation of volatile organic compounds tends to take place in the first few hours after emission, SOA can continue to evolve chemically over its atmospheric lifetime. Simulating this chemical aging over an extended time in the laboratory has proven to be challenging. We present here a procedure for studying SOA aging in laboratory chambers that is applied to achieve 36 h of oxidation. The formation and evolution of SOA from the photooxidation of m-xylene under low-NO_x conditions and in the presence of either neutral or acidic seed particles is studied. In SOA aging, increasing molecular functionalization leads to less volatile products and an increase in SOA mass, whereas gas- or particle-phase fragmentation chemistry results in more volatile products and a loss of SOA. The challenge is to discern from measured chamber variables the extent to which these processes are important for a given SOA system. In the experiments conducted, m-xylene SOA mass, calculated under the assumption of size-invariant particle composition, increased over the initial 12–13 h of photooxidation and decreased beyond that time, suggesting the existence of fragmentation chemistry. The oxidation of the SOA, as manifested in the O:C elemental ratio and fraction of organic ion detected at m/z 44 measured by the Aerodyne aerosol mass spectrometer, increased continuously starting after 5 h of irradiation until the 36 h termination. This behavior is consistent with an initial period in which, as the mass of SOA increases, products of higher volatility partition to the aerosol phase, followed by an aging period in which gas- and particle-phase reaction products become increasingly more oxidized. When irradiation is stopped 12.4 h into one experiment, and OH generation ceases, minimal loss of SOA is observed, indicating that the loss of SOA is either light- or OH-induced. Chemical ionization mass spectrometry measurements of low-volatility m-xylene oxidation products exhibit behavior indicative of continuous photooxidation chemistry. A condensed chemical mechanism of m-xylene oxidation under low-NO_x conditions is capable of reproducing the general behavior of gas-phase evolution observed here. Moreover, order of magnitude analysis of the mechanism suggests that gas-phase OH reaction of low volatility SOA precursors is the dominant pathway of aging in the m-xylene system although OH reaction with particle surfaces cannot be ruled out. Finally, the effect of size-dependent particle composition and size-dependent particle wall loss rates on different particle wall loss correction methods is discussed