Hamed (Mahmood) Dehnavi Avatar

Hamed (Mahmood) Dehnavi

Mechanical/Structural Engineer

PhD student with extensive experience in design concepts and techniques. Possess a comprehensive understanding of thermofluid systems, structural design and computer aided design tools. Excel at engineering judgment, leadership, problem solving, adaptability, project management, communications and...
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experience

Graduate Research Assistant  
University of Hawaii at Manoa, August 2009 to June 2014, Honolulu, Hawaii United States

• Investigated the application of composite nanostructures in lithium batteries. Comprehensive knowledge of the next generation commercial batteries: lithium sulfur batteries. Achieved 50% weight reduction compared to conventional electrodes by using a novel carbon nanotube structure. Won the best research presentation award in the REIS program. Improved the existing standard operating procedures (SOPs) and led the training of other lab members. • Responsibilities included: Component Design and Optimization, Nanostructure Analysis, Design Fabrication, System Maintenance and Modification, Design of Experiment, Data Analysis and Root Cause Analysis • Experience with fundamental structural design and analysis, finite element models, and analytical methods. Hands-on experience with growth and modification of carbon nanotubes, battery fabrication, chemical vapor deposition (CVD) and composites fabrication. Improved the fracture toughness of a continuous carbon fiber-reinforced composite material by 30% using carbon nanotubes. Patent under preparation. • Experience with design and development of biomedical devices. Designed and built a pain-free adhesive bandage; Experience with taking products from conception to production. Patent submitted. Team leader in the UH Manoa Business Plan competition to pursue commercialization of this product. Placed 4th out of 45 teams. • Served as Mechanical Engineering Student Representative by lobbying for grants and assisting graduate students with documentation to meet GSO requirements and specifications. Secured a travel grant for an ME student to present their research at an international conference. Led the development of a new budget management and awardee selection procedure • Studied the sooting behavior of diffusion flames under microgravity conditions. Validated numerical model with experiments; Developed model for soot-free conditions in combustion devices. Results can be used to eliminate soot from combustion devices; Collaborated with external researchers. Published and presented the results at a national conference. Fundamental knowledge of propulsion systems. Comprehensive understanding of heat transfer and fluid mechanics. • Developed new design and teaching methodology of a course in engineering programming. Established leadership and teamwork skills through collaboration with graduate students from multiple universities. Experience with modern techniques in STEM education

Research Assistant  
Ferdowsi University of Mashhad, December 2007 to April 2009

• Hands-on experience with internal combustion engines. Modified a variable compression ratio engine to HCCI mode and conducted experiments. Studied the effect of exhaust gas recirculation on the performance and emissions of the engine. Published results in two international conference papers as a co-author. • Experience with design of HVAC systems and Heat Exchangers. Experience with CFD and CAD modeling

education

University of Hawai'i at Manoa  
Master Of Science, Mechanical Engineering, Aug, 2009 to May, 2012


Ferdowsi University of Mashad  
Bachelor of Science, Mechanical Engineering, Jan, 2004 to Jan, 2009


publications

A numerical study on the soot-free conditions of spherical diffusion flames     
Published by (Combustion Institute Central States Meeting, April 22-24, Dayton, OH 2012)
Authors: Hamed (Mahmood) Dehnavi.  Published April 23, 2012

The soot free conditions of transient ethylene/oxygen/nitrogen spherical diffusion flames supported by a porous spherical burner were investigated numerically using detailed chemistry and transport coefficients. Radiative heat loss from the flame is included with the heat loss rate described by a statistical narrow-band model and a discrete ordinates method. The computations simulate soot free ethylene flames at atmospheric pressure, which were observed experimentally using the NASA GRC 2.2-s drop tower. These flames are initially sooty but turn soot-free between 1-2 s after the ignition. Fifteen normal (fuel flowing into the oxidizer) and inverse (oxidizer flowing into fuel) flames were modeled. The fuel and oxidizer concentrations are chosen such that a broad range of adiabatic temperatures (2251-2628K) and mixture fractions (0.317-0.754) are included. The results indicate that the flames are soot free when there is no region where the carbon to oxygen atom ratio exceeds 0.47 and the temperature exceed 1425K. These values are only slightly different from those recently published for similar flames.