A Tangent-Plane, Marker-Particle Method For The Computation Of Three-Dimensional Solid Surfaces Evolving By Surface Diffusion On A Substrate, Ping Du, Mikhail Khenner, Harris Wong
We introduce a marker-particle method for the computation of three-dimensional solid surface morphologies evolving by surface diffusion. The method does not use gridding of surfaces or numerical differentiation, and applies to surfaces with finite slopes and overhangs. We demonstrate the method by computing the evolution of perturbed cylindrical wires on a substrate. We show that computed growth rates at early times agree with those predicted by the linear stability analysis. Furthermore, when the marker particles are redistributed periodically to maintain even spacing, the method can follow breakup of the wire.
Oscillatory And Monotonic Modes Of Long-Wave Marangoni Convection In A Thin Film, 2009 Western Kentucky University
Oscillatory And Monotonic Modes Of Long-Wave Marangoni Convection In A Thin Film, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev
We study long-wave Marangoni convection in a layer heated from below. Using the scaling k=O#1;#3;Bi#2;, where k is the wave number and Bi is the Biot number, we derive a set of amplitude equations. Analysis of this set shows presence of monotonic and oscillatory modes of instability. Oscillatory mode has not been previously found for such direction of heating. Studies of weakly nonlinear dynamics demonstrate that stable steady and oscillatory patterns can be found near the stability threshold.
Thickness-Dependent Spontaneous Dewetting Morphology Of Ultrathin Ag Films, 2009 Washington University in St Louis
Thickness-Dependent Spontaneous Dewetting Morphology Of Ultrathin Ag Films, H Krishna, R Sachan, J Strader, C Favazza, Mikhail Khenner, Ramki Kalyanaraman
We show here that the morphological pathway of spontaneous dewetting of ultrathin Ag films on SiO2 under nanosecond laser melting is found to be film thickness dependent. For films with thickness h between 2<=h<=9.5 nm, the intermediate stages of the morphology consisted of bicontinuous structures. For films 11.5<=h<=20 nm, the intermediate stages consisted of regularly-sized holes. Measurement of the characteristic length scales for different stages of dewetting as a function of film thickness showed a systematic increase, which is consistent with the spinodal dewetting instability over the entire thickness range investigated. This change in morphology with thickness is consistent with observations made previously for polymer films [A. Shama et al, Phys. Rev. Lett., v81, pp3463 (1998); R. Seemann et al, J. Phys. Cond. Matt., v13, pp4925, (2001)]. Based on the behavior of free energy curvature that incorporates intermolecular forces, we have estimated the morphological transition thickness for Ag on SiO2. The theory predictions agree well with observations for Ag. These results show that it is possible to form a variety of complex Ag nanomorphologies in a consistent manner, which could be useful in optical applications of Ag surfaces, such as in surface enhanced Raman sensing.
Apolar Ortho-Phenylene Ethynylene Oligomers: Conformational Ordering Without Intermolecular Aggregation, 2009 University of Massachusetts - Amherst
Apolar Ortho-Phenylene Ethynylene Oligomers: Conformational Ordering Without Intermolecular Aggregation, Jing Jiang, Morris M. Slutsky, Ticora V. Jones, Gregory N. Tew
Gregory N. Tew
This paper describes the characterization of solvent induced folding behavior for non-polar (NP) alkoxy substituted ortho-phenylene ethynylene (o-PE) oligomers. Oligomers of lengths up to nine units have been shown to adopt helical conformations in heptane by NMR and CD spectroscopy, while chloroform promotes extended conformations. Surprisingly, the molar ellipticity values found in heptane for these oligomers are very small compared to other literature values of meta-phenylene ethynylene (m-PE) folded systems; however, comparable molar ellipticity values were found for a closed macrocyclic o-PE suggesting the weak ellipticity is a molecular-feature rather than a quality of folding indicator.
Viscosities And Densities Of Binary And Ternary Blends Of Palm Oil + Palm Biodiesel + Diesel Fuel At Different Temperatures, Abdul Aziz Abdul Raman
Abdul Aziz Abdul Raman
Vegetable oil-based fuels are promising alternative fuels for diesel engines because of their environmental and strategic advantages. In this work, binary and ternary blends of palm oil, biodiesel, and diesel fuel were prepared, and dynamic viscosities and densities of blends were measured as functions of temperature. The binary and ternary blends demonstrate a temperature-dependent behavior, and viscosities and densities decreased nonlinearly and linearly with temperature, respectively. The evaluation of the measured viscosities of binary and ternary blends was completed, and the best correlation was obtained by a polynomial regression. © 2010 American Chemical Society.
Evolution Of Block-Copolymer Order Through A Moving Thermal Zone, 2009 University of Akron
Evolution Of Block-Copolymer Order Through A Moving Thermal Zone, Kevin G. Yager, Nathaniel J. Fredin, Xiaohua Zhang, Brian C. Berry, Alamgir Karim, Ronald L. Jones
We investigate block-copolymer (BCP) thin film ordering kinetics during annealing across a moving in-plane temperature gradient. We operate in the so-called cold zone annealing (CZA) regime, where ordering temperatures are above the glass-transition, but well below the order-disorder transition. By measuring the order through the in-plane gradient, using atomic force microscopy and grazing-incidence small-angle X-ray scattering (GISAXS), we confirm that CZA greatly enhances ordering kinetics, as compared to uniform oven annealing. The maximal ordering occurs over a narrow range of the heating-up phase, and not during the subsequent cooling phase. The large grain sizes obtained using CZA are due to ...
Retrofit Of Distillation Columns In Biodiesel Production Plants, 2009 University of Nebraska Lincoln
Retrofit Of Distillation Columns In Biodiesel Production Plants, Yasar Demirel, N. Nguyen
Column grand composite curves and the exergy loss profiles produced by the Column-Targeting Tool of the Aspen Plus simulator are used to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a biodiesel production plant. Effectiveness of the retrofits is assessed by means of thermodynamics and economic improvements. We have considered a biodiesel plant utilizing three distillation columns to purify biodiesel (fatty acid methyl ester) and byproduct glycerol as well as reduce the waste. The assessments of the base case simulation have indicated the need for modifications for the distillation columns ...
Observation Of A Characteristic Length Scale In The Healing Of Glassy Polymer Interfaces, 2009 University of Akron
Observation Of A Characteristic Length Scale In The Healing Of Glassy Polymer Interfaces, Guangcui Yuan, Clive Li, Sushil K. Satija, Alamgir Karim, Jack F. Douglas, Charles C. Han
We examine the evolution (‘healing’) of the interface between two polymer films at various temperatures below the glass transition temperature, Tg. Specifically, neutron reflectometry is used to study the relaxation of the interface between both unentangled and entangled deuterated polystyrene (d-PS) and hydrogenated polystyrene (h-PS) films in the glass state where these bilayer films are supported on silicon substrates. We find that the initially sharp interface between the glassy polymer layers broadens with time (t), but the average interfacial thickness Δσ(t) between these layers then saturates after long time to a thickness (ξp) in a range between 1 nm ...
Spr Imaging Study Of Dna Wrapped Single Wall Carbon Nanotube (Ssdna-Swcnt) Adsorption On A Model Biological (Collagen) Substrate, Jung Jin Park, Jeffrey A. Fagan, Ji Yeon Huh, Kalman B. Migler, Alamgit Karim, Dharmaraj Raghaven
The adsorption kinetics of single stranded-DNA dispersed single wall carbon nanotubes (ssDNA-SWCNTs) onto an immobilized collagen layer in a microfluidic channel was probed using surface plasmon resonance imaging (SPRi). The adsorption was measured for a range of both nanotube and solution parameters including the nanotube concentration, nanotube length, solution pH, and the type of medium (buffer and river water). The kinetic adsorption data suggests that the adsorption of the nanotubes to the collagen layer is irreversible in HEPES buffer, pH ≈ 7.4, at room temperature, with the nanotube adsorption displaying two different kinetic adsorption regimes for different concentration ranges. A ...
2009 Report Of Crerg Research Activities, 2009 Instituto Superior Engenharia Lisboa
2009 Report Of Crerg Research Activities, João F. Gomes
João F Gomes
No abstract provided.
A Short Method For The Design Of Reactive Distillation Column, 2009 Universidad de Guanajuato
A Short Method For The Design Of Reactive Distillation Column, Marcelino Carrera-Rodriguez, Juan Gabriel Segovia-Hernandez, Adrian Bonilla-Petriciolet
In this study, a short method for the design of reactive distillation is presented. The method is based on distillation lines and tray-by-tray calculations, and a new strategy is suggested to locate the reflux ratio, the number of stages, and feed tray. The material balances are solved from the outside (top and bottom) to the inside of the distillation column (feed), to ensure that the product compositions are met. To reduce the numerical difficulties, the method is based on the application of reaction-invariant composition variables. The synthesis of MTBE with the presence of inert is used as case of study ...
Carbon Accounting Initiatives: Case Study Of A Petroleum Refinery In Malaysia To Prepare For Future Carbon Market, Abdul Aziz Abdul Raman
Abdul Aziz Abdul Raman
Petroleum refining process produces a large amount of atmospheric pollutants including greenhouse gases which are attributed to global warming. The international community inevitably addressed the global warming issue by introducing a market-based mechanism known as Emission Trading Systems (ETS) under the Kyoto Protocol which imposes binding limits to developed nations using three flexibility mechanisms, including the Clean Development Mechanism (CDM). © School of Engineering, Taylor's University College.
Degradation Of Organic Pollutants In Domestic Wastewaters By Concrete Plates Containing Of Photocatalyst Nanoparticles, Masoud Rastegar
No abstract provided.
Toxicological Assessment Of Coated Versus Uncoated Rubber Granulates Obtained From Used Tires For Use In Sport Facilities, 2009 Instituto Superior Engenharia Lisboa
Toxicological Assessment Of Coated Versus Uncoated Rubber Granulates Obtained From Used Tires For Use In Sport Facilities, João F. Gomes
João F Gomes
Reuse of tire crumb in sport facilities is currently a very cost-effective waste management measure. Considering that incorporation of the waste materials in artificial turf would be facilitated if the rubber materials were already colored green, coatings were specifically developed for this purpose. This paper presents an experimental toxicological and environmental assessment aimed at comparing the obtained emissions to the environment in terms of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and ecotoxicity for coated and noncoated rubber granulates. This study is a comprehensive evaluation of the major potential critical factors related with the release of all of these classes of ...
Mining And Civilization, An Illustrated History, 2009 Laval University, Quebec City, Canada
Mining And Civilization, An Illustrated History, Fathi Habashi
Production Of Jet And Diesel Fuel Range Alkanes From Waste Hemicellulose-Derived Aqueous Solutions, 2009 University of Massachusetts - Amherst
Production Of Jet And Diesel Fuel Range Alkanes From Waste Hemicellulose-Derived Aqueous Solutions, George W. Huber, R. Xing, A. V. Subrahmanyam, H. Olcay, W. Qi, G. P. Van Walsum, H. P. Pendse
George W. Huber
In this paper we report a novel four-step process for the production of jet and diesel fuel range alkanes from hemicellulose extracts derived from northeastern hardwood trees. The extract is representative of a byproduct that could be produced by wood-processing industries such as biomass boilers or pulp mills in the northeastern U.S. The hemicellulose extract tested in this study contained mainly xylose oligomers (21.2 g/l xylose after the acid hydrolysis) as well as 0.31 g/l glucose, 0.91 g/l arabinose, 0.2 g/l lactic acid, 2.39 g/l acetic acid, 0.31 ...
Poly(Beta-Alanoid-Block-Beta-Alanine)S: Synthesis Via Cobalt-Catalyzed Carbonylative Polymerization And Self-Assembly, 2009 University of Akron Main Campus
Poly(Beta-Alanoid-Block-Beta-Alanine)S: Synthesis Via Cobalt-Catalyzed Carbonylative Polymerization And Self-Assembly, Shaohui Lin, Xinfei Yu, Yinfeng Tu, Hongyu Xu, Stephen Z. D. Cheng, Li Jia
The titled diblock copolymers are synthesized via cobalt-catalyzed living carbonylative polymerization of N-alkylaziridines under moderate pressures followed by a deprotection step. The poly(beta-alanine) block is solubilized by the poly(beta-alanoid) block in chloroform and remains fully hydrogen-bonded in the form of a sheet-like assembly.