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Full-Text Articles in Engineering
Thermoelectric Power Factor Of In2O3:Pd Nanocomposite Films., Otto J. Gregory, Matin Amani, Gustave C. Fralick
Thermoelectric Power Factor Of In2O3:Pd Nanocomposite Films., Otto J. Gregory, Matin Amani, Gustave C. Fralick
Chemical Engineering Faculty Publications
A nanocomposite exhibiting large thermoelectric powers and capable of operating at temperatures as high as 1100 °C in air was fabricated by embedding palladium nanoparticles into an indium oxide matrix via co-sputtering from metal and ceramic targets. Combinatorial chemistry techniques were used to systematically investigate the effect of palladium content in these nanocomposite films on thermoelectric response. Based on these rapid screening experiments, the thermoelectric properties of the most promising nanocomposites were evaluated as a function of post-deposition heat treatment at high temperatures. An n-type nanocomposite film was developed exhibiting a power factor of 4.5 x 10-4 W/m·K2 …
Thermoelectric Properties Of ZnXInYOX+1.5y Films, Otto J. Gregory, Matin Amani
Thermoelectric Properties Of ZnXInYOX+1.5y Films, Otto J. Gregory, Matin Amani
Chemical Engineering Faculty Publications
Ceramic thin film thermocouples are being developed to replace noble metal thermocouples operating within the harsh environments of advanced turbine engines used for power generation and propulsion. Seebeck coefficients as large as 158 V/°C were determined for indium oxide (In2O3) at 950°C and 256 V/°C for zinc oxide ZnO at 1250°C relative to platinum reference electrodes. Because these Seebeck coefficients are appreciably larger than those for metallic thermocouples, alloys in the system indium zinc oxide ZnxInyOx+1.5y were investigated by cosputtering from high purity ZnO and In2O3 targets. Thermocouple …
Hydration Repulsion Effects Of The Formation Of Supported Lipid Bylayers, Selver Ahmed, Rajesh Raman Madathingal, Stephanie L. Wunder, Yanjing Chen, Geoffrey D. Bothun
Hydration Repulsion Effects Of The Formation Of Supported Lipid Bylayers, Selver Ahmed, Rajesh Raman Madathingal, Stephanie L. Wunder, Yanjing Chen, Geoffrey D. Bothun
Chemical Engineering Faculty Publications
When zwitterionic lipids fuse onto substrates such as silica (SiO2), the water of hydration between the two approaching surfaces must be removed, giving rise to an effective hydration repulsion. Removal of water around the polar headgroups of the lipid and the silanols (SiOH) of SiO2 allows supported lipid bilayer (SLB) formation, although an interstitial water layer remains between the lipid and surface. The importance of hydration repulsion in SLB formation is demonstrated by monitoring fusion of zwitterionic lipids onto silica (SiO2) nanoparticles heat treated to control the silanol group (SiOH) density and thus the amount of bound …
Rotational Relaxation Times Of Individual Compounds With Simulations Of Molecular Asphalt Models, Liqun Zhang, Michael L. Greenfield
Rotational Relaxation Times Of Individual Compounds With Simulations Of Molecular Asphalt Models, Liqun Zhang, Michael L. Greenfield
Chemical Engineering Faculty Publications
The dynamical properties of a complex system incorporate contributions from the diverse components from which it is constituted. To study this relationship in a multicomponent system, relaxation times based on rotation autocorrelation functions in molecular dynamics simulations were analyzed for molecules in two sets of unmodified and polymer-modified model asphalt/bitumen systems over 298–473 K. The model asphalt systems were proposed previously to approximate the chemical and mechanical properties of real asphalts. Relaxations were modeled using a modified Kaulrausch–Williams–Watts function and were based on the third Legendre polynomial of normal vector time correlation functions for aromatic species asphaltene, polar aromatic, naphthene …
A Multiscale Gibbs-Helmholtz Constrained Cubic Equation Of State, Angelo Lucia
A Multiscale Gibbs-Helmholtz Constrained Cubic Equation Of State, Angelo Lucia
Chemical Engineering Faculty Publications
This paper presents a radically new approach to cubic equations of state (EOS) in which the Gibbs-Helmholtz equation is used to constrain the attraction or energy parameter, a. The resulting expressions for a(T, p) for pure components and a(T, p, x) for mixtures contain internal energy departure functions and completely avoid the need to use empirical expressions like the Soave alpha function. Our approach also provides a novel and thermodynamically rigorous mixing rule for a(T, p, x).When the internal energy departure function is computed using Monte …
Relaxation Time, Diffusion, And Viscosity Analysis Of Model Asphalt Systems Using Molecular Simulation, Liqun Zhang, Michael L. Greenfield
Relaxation Time, Diffusion, And Viscosity Analysis Of Model Asphalt Systems Using Molecular Simulation, Liqun Zhang, Michael L. Greenfield
Chemical Engineering Faculty Publications
Molecular dynamics simulation was used to calculate rotational relaxation time, diffusion coefficient, and zero-shear viscosity for a pure aromatic compound naphthalene and for aromatic and aliphatic components in model asphalt systems over a temperature range of 298–443 K. The model asphalt systems were chosen previously to represent real asphalt. Green–Kubo and Einstein methods were used to estimate viscosity at high temperature 443.15 K. Rotational relaxation times were calculated by nonlinear regression of orientation correlation functions to a modified Kohlrausch–Williams–Watts function. The Vogel–Fulcher–Tammann equation was used to analyze the temperature dependences of relaxation time, viscosity, and diffusion coefficient. The temperature dependences …
Mesophase Separation And Probe Dynamics In Protein-Polyelectrolyte Coacervates, A. Basak Kayitmazer, Himadri B. Bohidar, Kevin W. Mattison, Arijit Bose, Jayashri Sarkar, Akihito Hashidzume, Paul S. Russo, Werner Jaeger, Paul L. Dubin
Mesophase Separation And Probe Dynamics In Protein-Polyelectrolyte Coacervates, A. Basak Kayitmazer, Himadri B. Bohidar, Kevin W. Mattison, Arijit Bose, Jayashri Sarkar, Akihito Hashidzume, Paul S. Russo, Werner Jaeger, Paul L. Dubin
Chemical Engineering Faculty Publications
Protein–polyelectrolyte coacervates are self-assembling macroscopically monophasic biomacromolecular fluids whose unique properties arise from transient heterogeneities. The structures of coacervates formed at different conditions of pH and ionic strength from poly(dimethyldiallylammonium chloride) and bovine serum albumin (BSA), were probed using fluorescence recovery after photobleaching. Measurements of self-diffusion in coacervates were carried out using fluorescein-tagged BSA, and similarly tagged Ficoll, a non-interacting branched polysaccharide with the same size as BSA. The results are best explained by temporal and spatial heterogeneities, also inferred from static light scattering and cryo-TEM, which indicate heterogeneous scattering centers of several hundred nm. Taken together with previous dynamic …
Transition From Unilamellar To Bilameller Vesicles Induced By An Amphiphilic Biopolymer, Jae-Ho Lee, Vivek Argarwal, Arijit Bose, Gregory F. Payne, Srinivasa R. Raghavan
Transition From Unilamellar To Bilameller Vesicles Induced By An Amphiphilic Biopolymer, Jae-Ho Lee, Vivek Argarwal, Arijit Bose, Gregory F. Payne, Srinivasa R. Raghavan
Chemical Engineering Faculty Publications
We report some unusual structural transitions upon the addition of an amphiphilic biopolymer to unilamellar surfactant vesicles. The polymer is a hydrophobically modified chitosan and it embeds its hydrophobes in vesicle bilayers. We study vesicle-polymer mixtures using small-angle neutron scattering (SANS) and cryotransmission electron microscopy (cryo-TEM). When low amounts of the polymer are added to unilamellar vesicles of ca. 120 nm diameter, the vesicle size decreases by about 50%. Upon further addition of polymer, lamellar peaks are observed in the SANS spectra at high scattering vectors. We show that these spectra correspond to a co-existence of unilamellar and bilamellar vesicles. …
A Simple Extrusion Method For The Synthesis Of Aligned Silica Nanowires Using The Template Of A Rigid Surface Mesophase, Limin Liu, Grace Tan, Vivek Agarwal, Arijit Bose, Jibao He, Gary L. Mcpherson, Vijay T. John
A Simple Extrusion Method For The Synthesis Of Aligned Silica Nanowires Using The Template Of A Rigid Surface Mesophase, Limin Liu, Grace Tan, Vivek Agarwal, Arijit Bose, Jibao He, Gary L. Mcpherson, Vijay T. John
Chemical Engineering Faculty Publications
Long range alignment of silica nanowires has been accomplished by extrusion of a novel surfactant mesophase prior to silica synthesis.
Piezoresistive Properties Of Ito Strain Sensors Prepared With Controlled Nanoporosity, Otto J. Gregory, Tao You
Piezoresistive Properties Of Ito Strain Sensors Prepared With Controlled Nanoporosity, Otto J. Gregory, Tao You
Chemical Engineering Faculty Publications
A ceramic strain gage based on reactively sputtered indium-tinoxide (ITO) thin films is being developed to monitor the structural integrity of components employed in aerospace propulsion systems operating at temperatures in excess of 1500°C. The hightemperature stability and piezoresistive properties depend to a large extent on the thickness of the active ITO strain elements comprising these ceramic strain gages. Scanning electron microscopy of the thick ITO sensors revealed a partially sintered microstructure consisting of a contiguous network of submicrometer ITO particles with well-defined necks and isolated nanoporosity. It appeared that densification of the ITO particles was retarded during high-temperature exposure …
Numerical Investigation Of Boundary Conditions For Moving Contact Line Problems, Sandesh Somalinga, Arijit Bose
Numerical Investigation Of Boundary Conditions For Moving Contact Line Problems, Sandesh Somalinga, Arijit Bose
Chemical Engineering Faculty Publications
When boundary conditions arising from the usual hydrodynamic assumptions are applied, analyses of dynamic wetting processes lead to a well-known nonintegrable stress singularity at the dynamic contact line, necessitating new ways to model this problem. In this paper, numerical simulations for a set of representative problems are used to explore the possibility of providing material boundary conditions for predictive models of inertialess moving contact line processes. The calculations reveal that up to Capillary number Ca=0.15, the velocity along an arc of radius 10Li (Li is an inner, microscopic length scale! from the dynamic contact line is independent of …
Investigation Of Wetting Hydrodynamics Using Numerical Simulations, David E. Finlow, Prakash R. Kota, Arijit Bose
Investigation Of Wetting Hydrodynamics Using Numerical Simulations, David E. Finlow, Prakash R. Kota, Arijit Bose
Chemical Engineering Faculty Publications
Meniscus shapes from a simulation of a plate immersing into an infinitely deep liquid bath, for a range of outer length scales, have been obtained numerically. These have been compared with the leading‐order prediction from a three‐region asymptotic analysis done in the double limit, Capillary number, Ca→0, LS/LC→0, with Ca ln(LC/LS) of O(1), where LS and LC represent the slip length and an outer macroscopic length, respectively. For Ca<0.01, the numerically computed and the perturbation solutions show excellent agreement. Within this range of Ca, the meniscus slope at a distance 10LS from the dynamic contact line is geometry independent, that is, does not vary with changes …
Large Scale Isolation Of Expression Vector Cassette By Magnetic Triple Helix Affinity Capture, Srinivas V. Sonti, Matthew C. Griffor, T. Sano, S. Narayanswami, Arijit Bose, C. R. Cantor, Albert P. Kausch
Large Scale Isolation Of Expression Vector Cassette By Magnetic Triple Helix Affinity Capture, Srinivas V. Sonti, Matthew C. Griffor, T. Sano, S. Narayanswami, Arijit Bose, C. R. Cantor, Albert P. Kausch
Chemical Engineering Faculty Publications
No abstract provided.
Synthesis Of Aluminum Hydroxide Nanoparticles In Spontaneously Generated Vesicles, Iskandar I. Yaacob, Suhas Bhandarkar, Arijit Bose
Synthesis Of Aluminum Hydroxide Nanoparticles In Spontaneously Generated Vesicles, Iskandar I. Yaacob, Suhas Bhandarkar, Arijit Bose
Chemical Engineering Faculty Publications
Unilamellar vesicles, formed spontaneously by mixing single-tailed cationic (cetyl trimethyl ammonium tosylate, CTAT) and anionic aqueous solutions of (sodium dodecyl benzene sulfonate, SDBS) surfactants have been used as reactors for the aqueous phase precipitation of nanometer sized particles within their inner cores. AlCl3 solution was encapsulated within these vesicles, aluminum ions were replaced with sodium ions in the extravesicular phase, and sodium hydroxide was then added to the extravesicular region. Hydroxyl ions penetrate through the vesicle walls and react with the available aluminum in the intravesicular region to form the product. The morphology and sizes of these particles were examined …