N. P. Malcolm, Department of Mechanical Engineering, University of Texas at Austin; A. Heltzel, PC Krause and Associates, Inc; L. Shi, J. R. Howell, Department of Mechanical Engineering, University of Texas at Austin ASME Micro/Nanoscale Heat Transfer International Conference, Tainan, Taiwan, 2008.
Read MoreDynamic Thermal Management System Modeling of a More Electric Aircraft
K. McCarthy, E. A. Walters, A. Heltzel, PC Krause and Associates, Inc; R. Elangovan, G. Roe, W. Vannice, Boeing; C. Schemm, Lockheed Martin; J. Dalton, Avetec; S. Iden, P. Lamm, C. Miller, U.S. Air Force Research Laboratory; A. Susainathan, U.S. Air Force Aeronautical Systems Center Advancements in electrical, mechanical, and structural design onboard modern more electric aircraft have added significant stress to the thermal management systems (TMS). A thermal management system level analysis tool has been created in MATLAB/Simulink to facilitate rapid system analysis and optimization to meet the growing demands of modern aircraft. It is anticipated that the tracking of thermal energy through numerical integration will lead to more accurate predictions of worst case TMS sizing conditions. In addition, the nonproprietary nature of the tool affords users the ability to modify component models and integrate advanced conceptual designs that can be evaluated over multiple missions to determine the impact at a system level. 2008 SAE Power Systems Conference, November 11-13 2008, Bellevue, WA. Paper...
Read MoreSimulation of a Plasmonic Tip-Terminated Scanning Nanowire Waveguide for Molecular Imaging
Nathan P. Malcolm, Department of Mechanical Engineering, University of Texas at Austin; A. Heltzel, PC Krause and Associates, Inc; Konstantin V. Sokolov, Department of Biomedical Engineering, University of Texas M.D. Anderson Cancer Center; Li Shi and John R. Howell, Department of Mechanical Engineering, University of Texas at Austin Finite difference time domain simulation reveals plasmonic coupling and local field enhancement at the gap between the gold nanoparticle _NP_ tip of a ZnO nanowire _NW_ waveguide and a gold-coated substrate or a gold NP probe. The region of field enhancement is about three times smaller than the 100 nm diameter of the gold NP tip, making the NW waveguide grown on a transparent microcantilever well-suited for near field imaging of single molecules immobilized on a gold substrate or gold NP-labeled cell membranes with superior spatial resolution and signal to noise ratio. 2008 American Institute of Physics. _DOI:...
Read MoreOptoelectronic Property Modeling of Carbon Nanotubes Grafted with Gold Nanoparticles
A. Heltzel, PC Krause and Associates, Inc; Liangti Qu, Liming Dai, University of Dayton Research Institute A three-dimensional (3D) electrodynamic model is built using the finite-difference time-domain (FDTD) method to investigate the optical response of carbon nanotubes grafted with gold nanoparticles. Theoretical characterizations suggest an anisotropic response, in line with previously observed absorption peaks of such systems in the optical range. An investigation of geometric and wavelength dependences is conducted, predicting the ability to tune the sub-wavelength intensity enhancement for efficient localization and propagation. The support of electric field enhancement along the nanotube walls raises the possibility of utilizing such systems as plasmon generators and waveguides for optical signal propagation. Online at...
Read MoreSimulation of Charge Density and Field Distribution of a Gold Nanoparticle Tip-Terminated Scanning Nanowire Waveguide for Molecular Imaging
N. P. Malcolm, Department of Mechanical Engineering, University of Texas at Austin; A. Heltzel, PC Krause and Associates, Inc; A. Shi, J. R. Howell, Department of Mechanical Engineering, University of Texas at Austin A Finite Difference Time Domain (FDTD) simulation is employed to calculate electromagnetic field and charge density distributions at the junction between a gold nanoparticle (NP) tip of a scanning ZnO nanowire and gold NP bio-markers. This three-dimensional simulation calculates the magnetic and electric field components in a large matrix of Yee cells by solving Maxwell’s curl equations. An absorbing boundary condition is included to eliminate reflection back into the simulation chamber. In the specific simulations considered here, a laser pulse of single wavelength is incident on the backside of a transparent silicon dioxide micro-cantilever, and coupled into a ZnO nanowire grown from an opening on a metal coating of the front side of the cantilever. The simulation results reveal local field enhancement between the gold NP tip of the nanowire and only one of three 20 nm gold NPs with a 28 nm empty spacing between two adjacent NPs. The charge density distributions in the gold tip and the gold NP are calculated and correlated with the local field enhancement, which makes the gold tip of the scanning nanowire waveguide attractive for use in imaging gold NP bio-labels on cell membranes. Proceedings of 9th International Conference on Heat Transfer, 2009, San Francisco...
Read MoreLaser Nanosphere Lithography
Alex Heltzel, PC Krause and Associates, Inc. Book Chapter in Nanomanufacturing American Scientific Publishers, 2009. A. Heltzel, PC Krause and Associates, Inc. Book Chapter in...
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