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Full-Text Articles in Nanoscience and Nanotechnology

Slip-Jump Model For Carbon Combustion Synthesis Of Complex Oxide Nanoparticles, A. A. Markov, Mkhitar A. Hobosyan, Karen S. Martirosyan Jan 2016

Slip-Jump Model For Carbon Combustion Synthesis Of Complex Oxide Nanoparticles, A. A. Markov, Mkhitar A. Hobosyan, Karen S. Martirosyan

Physics and Astronomy Faculty Publications and Presentations

Carbon Combustion Synthesis of Oxides (CCSO) is a promising method to produce submicron- and nano- sized complex oxides. The CCSO was successfully utilized for producing several complex oxides, a complete theoretical model including the sample porosity, fl ow parameters and reaction energetics is needed to predict the combustion parameters for CCSO. In this work, we studied the ignition temperature and combustion wave axial temperature distribution, activation energy, combustion heat and thermal losses for a typical CCSO synthesis for cylindrical samples of Ni-Zn ferrites with high (>85%) porosity. We developed a two level combustion model of chemically active nano-dispersed mixture, using ...


Tio 2 Fibers: Tunable Polymorphic Phase Transformation And Electrochemical Properties, Edna Garcia, Qiang Li, Xing Sun, Karen Lozano, Yuanbing Mao May 2015

Tio 2 Fibers: Tunable Polymorphic Phase Transformation And Electrochemical Properties, Edna Garcia, Qiang Li, Xing Sun, Karen Lozano, Yuanbing Mao

Chemistry Faculty Publications and Presentations

A series of one-dimensional (1D) nanoparticle-assembled TiO2 fibers with tunable polymorphs were prepared via a novel and large scale ForceSpinning® process of titanium tetraisopropoxide (TTIP)/polyvinylpyrrolidone (PVP) precursor fibers followed with a thermal treatment at various calcinations temperatures. The thermal and structural transformations were characterized by thermogravimetric analysis/differential scanning calorimetry, scanning electron microscopy, and X-ray diffraction. The influence of polymorphic phase of the TiO2 fibers on the electrochemical performance in neutral aqueous 1 M Na2SO4 electrolyte was investigated. The polymorphic amorphous/anatase/rutile TiO2 fibers prepared at 450 °C achieved a highest capacitance of 21.2 F g−1 ...


Fabrication Of Yttrium Ferrite Nanoparticles By Solution Combustion Synthesis, A. A. Saukhimov, Mkhitar A. Hobosyan, Chamath Dannangoda, N. N. Zhumabekova, S. E. Kumekov Jan 2014

Fabrication Of Yttrium Ferrite Nanoparticles By Solution Combustion Synthesis, A. A. Saukhimov, Mkhitar A. Hobosyan, Chamath Dannangoda, N. N. Zhumabekova, S. E. Kumekov

Physics and Astronomy Faculty Publications and Presentations

The ternary oxide system Y-Fe-O presents fascinating magnetic properties that are sensitive to the crystalline size of particles. There is a major challenge to fabricate these materials in nano-crystalline forms due to particle conglomeration during nucleation and synthesis. In this paper we report the fabrication of nano sized crystalline yttrium ferrite by solution combustion synthesis (SCS) where yttrium and iron nitrates were used as metal precursors with glycine as a fuel. The magnetic properties of the product can be selectively controlled by adjusting the ratio of glycine to metal nitrates. Yttrium ferrite nano-powder was obtained by using three concentration of ...


Fluid Dynamic Modeling Of Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie Jan 2014

Fluid Dynamic Modeling Of Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie

Physics and Astronomy Faculty Publications and Presentations

This paper presents a direct numerical method based on gas dynamic equations to predict pressure evolution during the discharge of nanoenergetic materials. The direct numerical method provides for modeling reflections of the shock waves from the reactor walls that generates pressure-time fluctuations. The results of gas pressure prediction are consistent with the experimental evidence and estimates based on the self-similar solution. Artificial viscosity provides sufficient smoothing of shock wave discontinuity for the numerical procedure. The direct numerical method is more computationally demanding and flexible than self-similar solution, in particular it allows study of a shock wave in its early stage ...


An Integrated Multidisciplinary Nanoscience Concentration Certificate Program For Stem Education, Karen S. Martirosyan, Mikhail M. Bouniaev, Malik Rachmanov, Ahmed Touhami, Nazmul Islam, Davood Askari, Tarek Trad, Dmitri Litvinov, Sergey E. Lyshevski Dec 2013

An Integrated Multidisciplinary Nanoscience Concentration Certificate Program For Stem Education, Karen S. Martirosyan, Mikhail M. Bouniaev, Malik Rachmanov, Ahmed Touhami, Nazmul Islam, Davood Askari, Tarek Trad, Dmitri Litvinov, Sergey E. Lyshevski

Physics and Astronomy Faculty Publications and Presentations

Integration of nanoscience and nanotechnology curricula into the College of Science, Mathematics, and Technology (CSMT) at the University of Texas at Brownsville (UTB) is reported. The rationale for the established multidisciplinary Nanoscience Concentration Certificate Program (NCCP) is to: (i) develop nanotechnology-relevant courses within a comprehensive Science, Engineering and Technology curriculum, and, to offer students an opportunity to graduate with a certificate in nanoscience and nanotechnology; (ii) to contribute to students' success in achieving student outcomes across all college's majors, and, improve the breath, depth and quality of science, technology, engineering and mathematics (STEM) graduates' education; (iii) through NCCP, recruit ...


Charge And Discharge Behaviour Of Li-Ion Batteries At Various Temperatures Containing Licoo2 Nanostructured Cathode Produced By Ccso, Y. Y. Mamyrbayeva, R. E. Beissenov, Mkhitar A. Hobosyan, S. E. Kumekov, Karen S. Martirosyan Jan 2013

Charge And Discharge Behaviour Of Li-Ion Batteries At Various Temperatures Containing Licoo2 Nanostructured Cathode Produced By Ccso, Y. Y. Mamyrbayeva, R. E. Beissenov, Mkhitar A. Hobosyan, S. E. Kumekov, Karen S. Martirosyan

Physics and Astronomy Faculty Publications and Presentations

There are technical barriers for penetration market requesting rechargeable lithium-ion battery packs for portable devices that operate in extreme hot and cold environments. Many portable electronics are used in very cold (-40 °C) environments, and many medical devices need batteries that operate at high temperatures. Conventional Li-ion batteries start to suffer as the temperature drops below 0 °C and the internal impedance of the battery increases. Battery capacity also reduced during the higher/lower temperatures. The present work describes the laboratory made lithium ion battery behaviour features at different operation temperatures. The pouch-type battery was prepared by exploiting LiCoO2 cathode ...


Reactive Self-Heating Model Of Aluminum Spherical Nanoparticles, Karen S. Martirosyan, Maxim Zyskin Jan 2013

Reactive Self-Heating Model Of Aluminum Spherical Nanoparticles, Karen S. Martirosyan, Maxim Zyskin

Physics and Astronomy Faculty Publications and Presentations

Aluminum-oxygen reaction is important in highly energetic and high pressure generating systems. Recent experiments with nanostructured thermites suggest that oxidation of aluminum nanoparticles occurs in a few microseconds. Such rapid reaction cannot be explained by a conventional diffusion-based mechanism. We present a rapid oxidation model of a spherical aluminum nanoparticle, using Cabrera-Mott moving boundary mechanism, and taking self-heating into account. In our model, electric potential solves the nonlinear Poisson equation. In contrast with the Coulomb potential, a “double-layer” type solution for the potential and self-heating leads to enhanced oxidation rates. At maximal reaction temperature of 2000 C, our model predicts ...


Modeling And Simulation Of Pressure Waves Generated By Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie Nov 2012

Modeling And Simulation Of Pressure Waves Generated By Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie

Physics and Astronomy Faculty Publications and Presentations

This paper reports the modeling of pressure waves from the explosive reaction of nano-thermites consisting of mixtures of nanosized aluminum and oxidizer granules. Such nanostructured thermites have higher energy density (up to 26 kJ/cm3) and can generate a transient pressure pulse four times larger than that from trinitrotoluene (TNT) based on volume equivalence. A plausible explanation for the high pressure generation is that the reaction times are much shorter than the time for a shock wave to propagate away from the reagents region so that all the reaction energy is dumped into the gaseous products almost instantaneously and thereby ...