Open Access. Powered by Scholars. Published by Universities.®

Mechanical Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 3 of 3

Full-Text Articles in Mechanical Engineering

Hydrothermal Preparation Of Gd+3 -Doped Titanate Nanotubes: Magnetic Properties And Photovoltaic Performance, Hoda S. Hafez, M Saif, James T. Mcleskey Jr., M.S.A. Abdel-Mottaleb, I S. Yahia, T Story, W Knoff Jan 2009

Hydrothermal Preparation Of Gd+3 -Doped Titanate Nanotubes: Magnetic Properties And Photovoltaic Performance, Hoda S. Hafez, M Saif, James T. Mcleskey Jr., M.S.A. Abdel-Mottaleb, I S. Yahia, T Story, W Knoff

Mechanical and Nuclear Engineering Publications

Pure and Gd+3 -doped titanate nanotubes (TNTs) materials were synthesized by a hydrothermal method. Their morphology, optical properties, thermal stability, and magnetic properties were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), UV-Vis spectroscopy, thermal analysis, and magnetic measurements. It was found that doping renders Gd+3-TNT visible light active and results in smaller crystallite size and larger surface area as well as higher thermal stability compared to pure titanate nanotubes. The estimated magnetic moments point to presence of weak antiferromagnetic interaction. Application of the prepared Gd+3-TNT for modifying conventional photoanodes in polymer solar cells was attempted. Preliminary results show …


Nanostructured Solid-State Hybrid Photovoltaic Cells Fabricated By Electrostatic Layer-By-Layer Deposition, Rolf Kniprath, James T. Mcleskey Jr., Jürgen P. Rabe, Stefan Kirstein Jan 2009

Nanostructured Solid-State Hybrid Photovoltaic Cells Fabricated By Electrostatic Layer-By-Layer Deposition, Rolf Kniprath, James T. Mcleskey Jr., Jürgen P. Rabe, Stefan Kirstein

Mechanical and Nuclear Engineering Publications

We report on the fabrication of hybrid organic/inorganic photovoltaic cells utilizing layer-by-layer deposition of water-soluble polyions and nanocrystals. A bulk heterojunction structure was created consisting of alternating layers of the p-conductive polythiophene derivative poly[2-(3-thienyl)-ethoxy-4-butylsulfonate] and n-conductive TiO2nanoparticles. We fabricated working devices with the heterostructure sandwiched between suitable charge carrier blocking layers and conducting oxide and metal electrodes, respectively. We analyzed the influence of the thickness and nanostructure of the active layer on the cell performance and characterized the devices in terms of static and transient current response with respect to illumination and voltage conditions. We observed reproducible and stable photovoltaic …


A Realistic Modeling Of Fluid Infiltration In Thin Fibrous Sheets, Sudhakar Jaganathan, Hooman Vahedi Tafreshi, Behnam Pourdeyhimi Jan 2009

A Realistic Modeling Of Fluid Infiltration In Thin Fibrous Sheets, Sudhakar Jaganathan, Hooman Vahedi Tafreshi, Behnam Pourdeyhimi

Mechanical and Nuclear Engineering Publications

In this paper, a modeling study is presented to simulate the fluid infiltration in fibrous media. The Richards’ equation of two-phase flow in porous media is used here to model the fluid absorption in unsaturated/partially saturated fibrous thin sheets. The required consecutive equations, relative permeability, and capillary pressure as functions of medium’s saturation are obtained via fiber-level modeling and a long-column experiment, respectively. Our relative permeability calculations are based on solving the Stokes flow equations in partially saturated three-dimensional domains obtained by imaging the sheets’ microstructures. The Richards’ equation, together with the above consecutive correlations, is solved for fibrous media …