http://hdl.handle.net/10027/1232 Sun, 26 May 2013 01:33:13 GMT 2013-05-26T01:33:13Z http://hdl.handle.net/10027/8669 Atomic layer deposition and characterization of stoichiometric erbium oxide thin dielectrics on Si(1 0 0) using (CpMe)3Er precursor and ozone Xu, Runshen; Tao, Qian; Yang, Yi; Takoudis, Christos G. Thin stoichiometric erbium oxide films were atomic layer deposited on p-type Si(100) substrates using tris(methylcyclopentadienyl)erbium and ozone. The film growth rate was found to be 0.12 ± 0.01 nm/cycle with an atomic layer deposition temperature window of 170-330 ºC. X-ray photoelectron spectral (XPS) analysis of the resulting Er2O3 films indicated the as-deposited films to be stoichiometric with no evidence of carbon contamination. Studies of post deposition annealing effects on resulting films and interfaces were done using Fourier transforms infrared spectroscopy, XPS, glancing incidence X-ray diffraction, and optical surface profilometry. As-deposited Er2O3 films were found to crystallize in the cubic structure with dominant (222) orientation; no erbium silicate was found at the interface. After annealing at 800 ºC in N2 for 5 min, a new XPS feature was found and it was assigned to the formation of erbium silicate. As the annealing temperature was increased, the interfacial erbium silicate content was found to increase in the temperature range studied. NOTICE: this is the author’s version of a work that was accepted for publication in Applied Surface Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Applied Surface Science, [Vol 258, Issue 22, (2012 Sept 1)] DOI: 10.1016/j.apsusc.2012.05.019 Sat, 01 Sep 2012 05:00:00 GMT http://hdl.handle.net/10027/8669 2012-09-01T05:00:00Z http://hdl.handle.net/10027/8613 Thermal rectification in a fluid reservoir Murad, Sohail; Puri, Ishwar K. An organized nonuniform mass distribution in solids leads to a monotonically varying thermal conductivity in a nanomaterial so that the heat flux is directionally dependent. We investigate through molecular dynamics simulations if the influence of an organized mass distribution in a fluid also leads to thermal rectification. Heat transfer is monitored in a water reservoir placed between two (hot and cold) silicon walls. The distribution of the fluid in the reservoirs is organized by applying an external force to each water molecule in a specified direction, creating a density gradient. This external force is smaller than the intermolecular forces in water, in most cases by much more than an order of magnitude. The simulations reveal that mass graded fluid-containing nanosystems can be engineered to possess an asymmetric axial thermal conductance that leads to greater heat flow in the direction of decreasing mass density. The rectification improves as the thermal conductivity is enhanced by increasing the fluid density adjacent to a hot wall, since doing so decreases the inter facial resistance and increases the heat flux. © 2012 American Institute of Physics. © 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters (Murad, S. & Puri, I. K. 2012. Thermal rectification in a fluid reservoir. Applied Physics Letters, 100(12).) and may be found at http://apl.aip.org/resource/1/applab/v100/i12/p121901_s1. DOI: 10.1063/1.3696022 Thu, 01 Mar 2012 06:00:00 GMT http://hdl.handle.net/10027/8613 2012-03-01T06:00:00Z http://hdl.handle.net/10027/8560 Biomedical systems research - new perspectives opened by quantitative medical imaging. Linninger, Andreas A. Recent advances in quantitative imaging allow unprecedented views into cellular chemistry of whole organisms in vivo. These novel imaging modalities enable the quantitative investigation of spatio-temporal reaction and transport phenomena in the living animal or the human body. This article will highlight the significant role that rigorous systems engineering methods can play for interpreting the wealth of in-vivo measurements. A methodology to integrate medical imaging modalities with rigorous computational fluid dynamics entitled image-based computational fluid dynamics (iCFD) will be introduced. The quantitative analysis of biological systems with rigorous mathematical methods is expected to accelerate the introduction of novel drugs by providing a rational foundation for the systematic development of new medical therapies. Rigorous engineering methods not only advance biomedical research, but also aid the translation of laboratory research results into the bedside practice. NOTICE: this is the author’s version of a work that was accepted for publication in Computers and Chemical Engineering. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Computers and Chemical Engineering, Vol 36, Issue , (10 January 2012). DOI: 10.1016/j.compchemeng.2011.07.010 Sun, 01 Jan 2012 06:00:00 GMT http://hdl.handle.net/10027/8560 2012-01-01T06:00:00Z http://hdl.handle.net/10027/8552 Self-assembling process of flash nanoprecipitation in a multi-inlet vortex mixer to produce drug-loaded polymeric nanoparticles Shen, Hao; Hong, Seungpyo; Prud'homme, Robert; Liu, Ying We present an experimental study of self-assembled polymeric nanoparticles in the process of flash nanoprecipitation using a multi-inlet vortex mixer (MIVM). beta-Carotene and polyethyleneimine (PEI) are used as a model drug and a macromolecule, respectively, and encapsulated in diblock copolymers. Flow patterns in the MIVM are microscopically visualized by mixing iron nitrate (Fe(NO(3))(3)) and potassium thiocyanate (KSCN) to precipitate Fe(SCN) (x) ((3-x)+) . Effects of physical parameters, including Reynolds number, supersaturation rate, interaction force, and drug-loading rate, on size distribution of the nanoparticle suspensions are investigated. It is critical for the nanoprecipitation process to have a short mixing time, so that the solvent replacement starts homogeneously in the reactor. The properties of the nanoparticles depend on the competitive kinetics of polymer aggregation and organic solute nucleation and growth. We report the existence of a threshold Reynolds number over which nanoparticle sizes become independent of mixing. A similar value of the threshold Reynolds number is confirmed by independent measurements of particle size, flow-pattern visualization, and our previous numerical simulation along with experimental study of competitive reactions in the MIVM. Post print version of article may differ from published version. The original publication is available at springerlink.com; DOI: 10.1007/s11051-011-0354-7. Thu, 01 Sep 2011 05:00:00 GMT http://hdl.handle.net/10027/8552 2011-09-01T05:00:00Z