NATIONAL INSTITUTE OF AEROSPACE

Contact Us:

David Throckmorton
Vice President of Research
757.325.6724
david.throckmorton@nianet.org

James Closs
Director of Research Program Development
757.325.6903
james.closs@nianet.org

Carly Bosco
Director of NASA Langley Programs
757.325.6726
carly.bosco@nianet.org

Peter McHugh
Director of FAA Programs
757.325.6796
peter.mchugh@nianet.org  

Samantha Austin
Program Manager, Advanced Composites Consortium Integration
757.325.6705
samantha.austin@nianet.org

Godfrey Sauti

Tel: +1 (757) 864-8174; Fax:  +1 (757) 864-8312sauti_godfrey_bg

Email: godfrey.sauti@nianet.org

Research Interests

  • Materials Science,
  • Dielectric Spectroscopy. Measurements and modeling of the properties of heterogeneous dielectrics. Percolation, scaling and universality in composite dielectric properties.
  • Radiation transport, Simulation, Modeling and Testing  of Radiation Shielding Materials
  • Plasma Actuators
  • Nano-materials including Carbon and Boron Nitride Nanotubes
  • Software tools for measurement control and data analysis

Education

  • Ph.D. (2005), Physics, University of the Witwatersrand, South Africa
  • B.Sc. (Hons) (1999) , Physics, University of Zimbabwe

Current Research 

Multifunctional Polymer Nanocomposites.

The goals of this work are to develop multifunctional materials with a range of properties for use as sensors, actuators, and negative index metamaterials.

Polymer nano-composites fit this role as their properties can be tailored by controlling the composition and microstructure. The research explores the utilization of various nano inclusions, including carbon and boron nitride nanotubes and sheets to control the physical properties of multifunctional polymer nanocomposites and developing models for the relationship between the properties and the composition as well as micro (nano) structure. The work encompasses characterizing and modeling of the interaction of electromagnetic waves with nanocomposites and nanostructured materials.

Aeroelastically Tailored Wing

A major goal for subsonic fixed wing transport is to increase the range, decrease fuel burn, noise, emissions, and otherwise increase the efficiency of aircraft. This project is aimed at increasing aircraft performance by providing a light weight active wing/structure that adapts to the aerodynamic loads encountered in various parts of the flight profile. New materials and structures to achieve aeroelastic tailoring are being explored in a partnership with various NASA centers as well as industry and academia.

Nanomaterials Based Structures 

Nanotubes of carbon and boron nitride (CNTs and BNNTs) respectively are the strongest materials ever discovered by mankind. With high measured tensile strengths over 50 GPa and Young’s modulus of the order 1 TPa, these nanotubes are very promising for many high-strength, lightweight applications. However, it is not yet known how to harness these remarkable nanoscale attributes into the building of structures for real world, macroscale, applications without significant knockdowns in the properties. This project, which involves collaboration with NASA researchers at various centers, as well as industry and academic partners, is aimed at developing structural materials that inherit more of the properties of their underlying nano constituents.

Boron Nitride Nanotubes and Radiation Shielding Materials for Space Systems

The biggest challenge to long duration spaceflight is the radiation exposure of astronauts and equipment. On long duration missions, away from low earth orbit and the protection of the earth’s magnetic field, astronauts and electronic equipment endure mission limiting exposure to Galactic Cosmic Rays (GCRs) and Solar Particle Events (SPE’s). This work, which is in collaboration with researchers at NASA Langley Research Center (NASA LaRC), is intended to develop materials and systems that limit this exposure, thereby possibly extending mission duration and improving mission safety. The work includes computer modeling of radiation transport using among other tools the NASA LaRC developed On-Line Tool for the Assessment of Radiation in Space (OLTARIS), materials design, synthesis and testing. As part of this work, super strong boron nitride nanotubes are being explored as the basis for radiation shielding structural materials.

Single Barrier Dielectric Discharge Plasma Actuators

Dielectric barrier discharge devices are fundamental flow actuation devices that can be used in a variety of aeronautical applications, including: both fixed and rotary wing, internal flows, turbo-machinery, and wind turbines.  Their primary function is to impart momentum to low speed flow adjacent to the flush-mounted surface device. To date, they have found greatest application in control of steady and unsteady boundary layer flow separation. As such, DBD technology is directly relevant to 2010 National Aeronautics R&D Plan elements focused on increased efficiency, performance, and flow noise. Potential specific applications are many, including: on-demand airfoil and fuselage separation control for V/STOL aircraft, deployed landing gear noise reduction, rotorcraft retreating blade stall alleviation, control of tail boom vibrations due to cyclic rotor downwash, jet engine turbine blade separation at cruise conditions and as a source of controlled disturbance inputs for active high-speed laminar-flow-control techniques.  This project is conducted in collaboration with researchers at NASA LaRC, and is aimed at improving the performance of these actuators, as well as increasing their range of application by the use of innovative materials and designs.

Measurement Control and Data Analysis Software

As part of the work in various projects, a set of software tools is being developed for measurement control as well as data analysis. Currently this suite of tools covers modeling and measurements for dielectric spectroscopy, dielectric breakdown, direct current IV curves under a variety of conditions, controls for aeroelastically tailored wing models, as well as neutron exposure experiments. These tools are written in Mathematica, LabView, and Python, including wxPython Interfaces.

Recent Publications

  • Cheol Park, Jae-Woo Kim, Godfrey Sauti, Jin Ho Kang, Conrad S.  Lovell, Luke J Gibbons, Sharon E  Lowther,  Peter T Lillehei, Joycelyn S. Harrison, Negin  Nazem and Larry T Taylor, “Metallized nanotube polymer composites via supercritical fluid impregnation”, Journal of Polymer Science Part B: Polymer Physics, 50(6), 394-402, 2012.
  • Conrad S. Lovell, Jin Ho Kang, Godfrey Sauti, James M Fitz-Gerald, Cheol Park, “Shear piezoelectricity in single-wall carbon nanotube/poly(γ-benzyl-L-glutamate) composites”,  Journal of Polymer Science Part B: Polymer Physics, vol. 48, issue 22, pp. 2355-2365
  • W. H. Zhong, C. A. Ulven, C. Park, R. G. Maguire, J. H. Kang and  G. Sauti, M. A. Fuqua, “Polymer Nanocomposites and Functionalities” (173 manuscript pages), Encyclopedia of Nanoscience and Nanotechnology 2nd, Edited by H. S. Nalwa, American Scientific Publishers, Vol. 21 pp. 171-281, 2011.
  • D. S. McLachlan and G. Sauti. “The ac and dc conductivity (dielectric constant) of composites.” Dielectrics Newsletter, 23:1-4, February 2008.
  • David S. McLachlan, Godfrey Sauti, and Cosmas Chiteme. “Static dielectric function and scaling of the ac conductivity for universal and nonuniversal percolation systems.” Phys. Rev. B, 76:014201, 2007.
  • Godfrey Sauti, Antoinette Can, David S. McLachlan, and Mathias Herrmann. “The ac conductivity of liquid-phase-sintered silicon carbide.” Journal of the American Ceramic Society, 90(8):2446-2453, 2007.
  • Godfrey Sauti and David S. McLachlan. “Impedance and modulus spectra of the percolation system silicon-polyester resin and their analysis using the two exponent phenomenological percolation equation.” Journal of Materials Science, 42:6477-6488, 2007.
  • Cosmas Chiteme, David S. McLachlan and Godfrey Sauti. “The ac and dc percolative conductivity of magnetite cellulose acetate composites.” Physical. Review. B, 75:094202, 2007.
  • A. Can, D.S. McLachlan, G. Sauti and M. Herrmann. “Relationships between microstructure and electrical properties of liquid-phase sintered silicon carbide materials using impedance spectroscopy.” Journal of the European Ceramic Society, 27(2-3):13611363, 2007.
  • K.F. Cai, D.S. McLachlan, G. Sauti, and E. Mueller. “The effects of annealing on thermal and electrical properties of reaction-bonded AlN ceramic.” Solid State Sciences, 7(8):945-949, 2005.
  • Cheol Park, John Wilkinson, Sumanth Banda, Zoubeida Ounaies, Kristopher E. Wise, Godfrey Sauti, Peter T.  Lillehei and  Joycelyn S. Harrison, “Aligned single-wall carbon nanotube polymer composites using an electric field.”  Journal of Polymer Science Part B: Polymer Physics, vol. 44, issue 12, pp. 1751-1762.
  • David S. McLachlan and Godfrey Sauti. “The ac and dc conductivity of nanocomposites.” Journal of Nanomaterials, 2007:30389, 2007.

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