Physics Commons^™

Erratum: Experimental Study Of The Role Of Physicochemical Surface Processing On The In Ability Of Mineral Dust Particles (Atmospheric Chemistry And Physics (2011) 11 (11131-11144)), D. Niedermeier, S. Hartmann, T. Clauss, H. Wex, A. Kiselev, R. C. Sullivan, P. J. Demott, M. D. Petters, P. Reitz, J. Schneider, E. Mikhailov, B. Sierau, O. Stetzer, B. Reimann, U. Bundke, R. A. Shaw, A. Buchholz, T. F. Mentel, F. Stratmann

Michigan Tech Publications

No abstract provided.

Experimental Study Of The Role Of Physicochemical Surface Processing On The In Ability Of Mineral Dust Particles, D. Niedermeier, S. Hartmann, T. Clauss, H. Wex, A. Kiselev, R. C. Sullivan, P. J. Demott, M. D. Petters, P. Reitz, J. Schneider, E. Mikhailov, B. Sierau, O. Stetzer, B. Reimann, U. Bundke, R. A. Shaw, A. Buchholz, T. F. Mentel, F. Stratmann

Michigan Tech Publications

During the measurement campaign FROST 2 (FReezing Of duST 2), the Leipzig Aerosol Cloud Interaction Simulator (LACIS) was used to investigate the influence of various surface modifications on the ice nucleating ability of Arizona Test Dust (ATD) particles in the immersion freezing mode. The dust particles were exposed to sulfuric acid vapor, to water vapor with and without the addition of ammonia gas, and heat using a thermodenuder operating at 250 °C. Size selected, quasi monodisperse particles with a mobility diameter of 300 nm were fed into LACIS and droplets grew on these particles such that each droplet contained a …

Heterogeneous Ice Nucleation: Exploring The Transition From Stochastic To Singular Freezing Behavior, D. Niedermeier, R. A. Shaw, S. Hartmann, H. Wex, T. Clauss, J. Voigtländer, F. Stratmann

Michigan Tech Publications

Heterogeneous ice nucleation, a primary pathway for ice formation in the atmosphere, has been described alternately as being stochastic, in direct analogy with homogeneous nucleation, or singular, with ice nuclei initiating freezing at deterministic temperatures. We present an idealized, conceptual model to explore the transition between stochastic and singular ice nucleation. This "soccer ball" model treats particles as being covered with surface sites (patches of finite area) characterized by different nucleation barriers, but with each surface site following the stochastic nature of ice embryo formation. The model provides a phenomenological explanation for seemingly contradictory experimental results obtained in our research …

Homogeneous And Heterogeneous Ice Nucleation At Lacis: Operating Principle And Theoretical Studies, S. Hartmann, D. Niedermeier, J. Voigtländer, T. Clauss, R. A. Shaw, H. Wex, A. Kiselev, F. Stratmann

Michigan Tech Publications

At the Leipzig Aerosol Cloud Interaction Simulator (LACIS) experiments investigating homogeneous and heterogeneous nucleation of ice (particularly immersion freezing in the latter case) have been carried out. Here both the physical LACIS setup and the numerical model developed to design experiments at LACIS and interpret their results are presented in detail. < br> < br> Combining results from the numerical model with experimental data, it was found that for the experimental parameter space considered, classical homogeneous ice nucleation theory is able to predict the freezing behavior of highly diluted ammonium sulfate solution droplets, while classical heterogeneous ice nucleation theory, together with the assumption of …

Computed Tomography Reconstruction: Investigating The Effect Of Varying Circle Diameter, William F. Sanders Iv

Browse all Theses and Dissertations

In Computed Tomography (CT) reconstruction, several methods for determining the intensity of individual pixels from the back-projection of the scanned profiles exist. The standard reconstruction method uses linear interpolation between ray values to determine pixel intensity. This study quantifies the effects of varying circle diameter on the accuracy of an alternative method where the pixel is approximated as a circle and the area contributions calculated.

A library of 104 scans in 3 image families was created by a synthetic CT scanner and reconstructed with circle radii from 0.1 to 1.0 pixel in 0.1 pixel steps. Images were compared against a …

Growth And Characterization Of Carbon Nanomaterials, Jay Patel

Browse all Theses and Dissertations

In this thesis, single and multi-layered graphene films were epitaxially grown on either Si-face or C-face of SiC single crystal substrates. The film growth conditions, such as decomposition temperatures and pressures, and their surface morphologies were optimized. These films were then characterized by using surface analysis tools including SEM, TEM, AFM evanescent wave microscopy and electron educed spectroscopy. In addition to studying graphene decomposed from SiC crystals, carbon nanotube material was fabricated using a floating catalyst technique. These carbon nanotube material was then studied for potential cathode applications in this thesis. Field emission properties of these cathodes was measured and …