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262 full-text articles. Page 7 of 9.

Optimal Control And Cfd Modeling For Heat Flux Estimation Of A Baking Process, Abdellah Ousegui 2011 Laval University

Optimal Control And Cfd Modeling For Heat Flux Estimation Of A Baking Process, Abdellah Ousegui

Abdellah Ousegui

No abstract provided.


Investigation Of Hydrodynamic Scaling Relationships In Shallow Spouted Beds, Irma Deytia Lima Rojas 2011 University of Tennessee, Knoxville

Investigation Of Hydrodynamic Scaling Relationships In Shallow Spouted Beds, Irma Deytia Lima Rojas

Doctoral Dissertations

Important global hydrodynamic relationships for shallow spouted beds of high-density particles were characterized in terms of three features: minimum spouting velocity, overall bed pressure drop at minimum spouting velocity; and fountain height. Spouted bed literature is sparse for shallow beds (static particle depth to bed diameter ≤ 1) and beds with heavy particles (density > 3000 kg/m3). Correlations for such beds were developed here by varying column diameter, static bed height, particle diameter, particle density, gas density and gas flow in an ambient temperature and pressure bed.

The degree of correlation between each of the observed hydrodynamic features and a ...


Dynamics Of Polymeric Solutions In Complex Kinematics Bulk And Free Surface Flows: Multiscale/Continuum Simulations And Experimental Studies, Arash Abedijaberi 2011 University of Tennessee, Knoxville

Dynamics Of Polymeric Solutions In Complex Kinematics Bulk And Free Surface Flows: Multiscale/Continuum Simulations And Experimental Studies, Arash Abedijaberi

Doctoral Dissertations

While rheological and microstructural complexities have posed tremendous challenges to researchers in developing first principles models and simulation techniques that can accurately and robustly predict the dynamical behaviour of polymeric flows, the past two decades have offered several significant advances towards accomplishing this goal. These accomplishments include: (1). Stable and accurate formulation of continuum-level viscoelastic constitutive models and their efficient implementation using operator splitting methods to explore steady and transient flows in complex geometries, (2). Prediction of rheology of polymer solutions and melts based on micromechanical models as well as highly parallel self-consistent multiscale simulations of non-homogeneous flows. The main ...


Reactive Molecular Dynamics Study Of Proton Transport In Polymer Electrolyte Membranes, Myvizhi Esai Selvan, David Keffer, Shengting Cui 2011 University of Tennessee - Knoxville

Reactive Molecular Dynamics Study Of Proton Transport In Polymer Electrolyte Membranes, Myvizhi Esai Selvan, David Keffer, Shengting Cui

David Keffer

Dynamical properties of water and protons in Nafion with an equivalent weight of 1144 are studied using the recently developed reactive molecular dynamics (RMD) algorithm at various water contents. The structural diffusion of a proton along the aqueous domains is modeled via a mechanism similar to that observed in bulk aqueous systems. The algorithm implements reactivity in classical MD simulations by three steps: (i) satisfaction of the trigger, (ii) instantaneous reaction, and (iii) local equilibration. Two different schemes (Method 1 and Method 2) of execution of the algorithm are investigated, which differ in terms of the range of the local ...


A Review Of X-Ray Flow Visualization With Applications To Multiphase Flows, Theodore J. Heindel 2011 Iowa State University

A Review Of X-Ray Flow Visualization With Applications To Multiphase Flows, Theodore J. Heindel

Mechanical Engineering Publications

Flow visualization and characterization of multiphase flows have been the quest of many fluid mechanicians. The process is fairly straight forward only when there is good optical access (i.e., the vessel is not opaque or there are appropriate viewing ports) and the flow is transparent, implying a very low volume fraction of the dispersed phase; however, when optical access is not good or the fluid is opaque, alternative methods must be developed. Several different noninvasive visualization tools have been developed to provide high-quality qualitative and quantitative data of various multiphase flow characteristics, and overviews of these methods have appeared ...


Rayleigh Test Apparatus Design Report, Josef Duller, Owen Raybould, James Nicovich 2011 California Polytechnic State University - San Luis Obispo

Rayleigh Test Apparatus Design Report, Josef Duller, Owen Raybould, James Nicovich

Mechanical Engineering

The Rayleigh Test Apparatus is a device that will be used to test the thermodynamic properties of Nitrous Oxide to assess the feasibility of using this fluid as a coolant for a hybrid rocket aero spike. The aero spike is intended to redirect the propulsion flow as it leaves the engine to create a more efficient flow pattern at low and high altitudes. However, there are issues of overheating which leads to melting of the aero spike. For this reason, the use of nitrous oxide (N2O) as a coolant is being explored. N20 is being considered because it is already ...


L'Oreal Waste Minimization, Caitlin Burns, Joe Baugh, Allen Busick, Ryan Black, Emily Evans, Matthew Margis 2011 University of Arkansas, Fayetteville

L'Oreal Waste Minimization, Caitlin Burns, Joe Baugh, Allen Busick, Ryan Black, Emily Evans, Matthew Margis

Chemical Engineering Undergraduate Honors Theses

No abstract provided.


Cell Power Input Or Hydrodynamics - Which Is More Important In Flotation?, Sami Grönstrand, Alejandro Yañez, Gijsbert Wierink, Juha Tiitinen 2011 Selected Works

Cell Power Input Or Hydrodynamics - Which Is More Important In Flotation?, Sami Grönstrand, Alejandro Yañez, Gijsbert Wierink, Juha Tiitinen

Gijsbert Wierink

This paper presents the results of the studies carried out at Chuquicamata Concentrator, related to the hydrodynamic set-up of the forced air TankCell® 300. This 300 m3 cell was operating as the first rougher of the line of cells, and its performance was compared to a parallel line with TankCell® 160 machines. In the 300 m3 cell, three different hydrodynamic set-ups were trialed. First, using the new FloatForce® mechanism with the standard rotating speed in the TankCell 300, secondly adding one auxiliary FlowBooster™ impeller in the shaft while maintaining speed, and finally keeping the FloatForce and FlowBooster, but reducing the ...


Toward A Predictive Understanding Of Water And Charge Transport In Proton Exchange Membranes, Myvizhi Esai Selvan, Elisa Calvo-Muñoz, David Keffer 2011 University of Tennessee - Knoxville

Toward A Predictive Understanding Of Water And Charge Transport In Proton Exchange Membranes, Myvizhi Esai Selvan, Elisa Calvo-Muñoz, David Keffer

David Keffer

An analytical model for water and charge transport in highly acidic and highly confined systems such as proton exchange membranes of fuel cells is developed and compared to available experimental data. The model is based on observations from both experiment and multiscale simulation. The model accounts for three factors in the system including acidity, confinement, and connectivity. This model has its basis in the molecular-level mechanisms of water transport but has been coarse-grained to the extent that it can be expressed in an analytical form. The model uses the concentration of H3O+ ion to characterize acidity, interfacial surface area per ...


A Combined Numerical And Experimental Study Of Hydrodynamics For An Air-Water External Loop Airlift Reactor, Deify Law, Samuel T. Jones, Theodore J. Heindel, Francine Battaglia 2011 Virginia Polytechnic Institute and State University

A Combined Numerical And Experimental Study Of Hydrodynamics For An Air-Water External Loop Airlift Reactor, Deify Law, Samuel T. Jones, Theodore J. Heindel, Francine Battaglia

Mechanical Engineering Publications

The external loop airlift reactor (ELALR) is a modified bubble column reactor that is composed of two vertical columns that are interconnected with two horizontal tubes and is often preferred over traditional bubble column reactors because they can operate over a wider range of conditions. In the present work, the gas-liquid flow dynamics in an ELALR was simulated using an Eulerian–Eulerian ensemble-averaging method in two-dimensional (2D) and three-dimensional (3D) coordinate systems. The computational fluid dynamics (CFD) simulations were compared to experimental measurements from a 10.2 cm diameter ELALR for superficial gas velocities ranging from 1 cm/s to ...


Stability And Growth Behavior Of Transition Metal Nanoparticles In Ionic Liquids Prepared By Thermal Evaporation: How Stable Are They Really?, Kai Richter, Alexander Birkner, Anja V. Mudring 2011 Iowa State University

Stability And Growth Behavior Of Transition Metal Nanoparticles In Ionic Liquids Prepared By Thermal Evaporation: How Stable Are They Really?, Kai Richter, Alexander Birkner, Anja V. Mudring

Anja V. Mudring

Recently we developed an access to metal- and metal-oxide colloids based on thermal evaporation of metals into ionic liquids (ILs). Here we present systematic studies on the long-time stability of gold and copper nanoparticles (NPs) in different ILs. The influence of metal concentration and temperature on the ripening of the as-prepared gold NPs in different ILs was investigated by transmission electron microscopy (TEM) and UV-vis absorption measurements. Short alkyl chain-length-methyl-imidazolium salts with weakly coordinating perfluorinated counter anions (PF6, BF4 or Tf2N, bis(trifluoromethanesulfonyl)amide) were found to be better stabilizers compared to ILs with cations bearing long alkyl chains (trihexyltetradecylphosphonium ...


A New Open-Framework Iron Borophosphate From Ionic Liquids: Kfe[Bp2o8(Oh)], Guangmei Wang, Anja V. Mudring 2011 Iowa State University

A New Open-Framework Iron Borophosphate From Ionic Liquids: Kfe[Bp2o8(Oh)], Guangmei Wang, Anja V. Mudring

Anja V. Mudring

A new open-framework iron borophosphate, KFe[BP2O8(OH)], has been obtained by ionothermal synthesis from KH2PO4, FeCl3∙4H2O, H3BO3 and [C4mpyr]Br (1-butyl-1-methylpyrrolidinium bromide). Single-crystal X-ray diffraction analysis shows that KFe[BP2O8(OH)] (monoclinic, P21/c, a = 9.372(2) Å , b = 8.146(2)Å , c = 9.587(2) Å, β = 101.18(3)°, V = 718.0(2)Å3 and Z = 4) has a three-dimensional (3-D) framework structure composed by {Fe(III)O5(OH)} octahedra as well as {BO3(OH)} and {PO4} tetrahedra. As anionic structural sub-unit, KFe[BP2O8(OH)], contains an infinite open-branched {[BP2O8(OH)]4-} chain which ...


The First Lanthanide Telluride-Bromide: La3te4br, A Valence Compound, Markus Larres, Anja V. Mudring, Gerd Meyer 2011 Iowa State University

The First Lanthanide Telluride-Bromide: La3te4br, A Valence Compound, Markus Larres, Anja V. Mudring, Gerd Meyer

Anja V. Mudring

The first ternary lanthanide telluride-bromide La3Te4Br was obtained from a mixture of LaTe and LaBr3 (in the presence of iridium) in a sealed tantalum container at elevated temperatures. The crystal structure (orthorhombic, Pnma, a = 1634.3(2), b = 435.0(1), c = 1426.6(2) pm, Z = 4, R1 (I0 > 2s(I0)) = 0.0349) is built from dicapped trigonal prisms of tellurium and bromine atoms surrounding lanthanum in two different ways. The dicapped trigonal prisms are connected via common edges to a threedimensional structure, in the same fashion as is known for the binary U3Te5. La3Te4Br is a valence compound ...


In-Situ Crystal Growth And Properties Of The Magnetic Ionic Liquid [C2mim][Fecl4], Tobias Backer, Oliver Breunig, Klaus Merz, Vera Vasylyeva, Anja V. Mudring 2011 Iowa State University

In-Situ Crystal Growth And Properties Of The Magnetic Ionic Liquid [C2mim][Fecl4], Tobias Backer, Oliver Breunig, Klaus Merz, Vera Vasylyeva, Anja V. Mudring

Anja V. Mudring

[C2mim][FeCl4] behaves like a paramagnetic liquid at room temperature. Specific heat measurements indicate that there is a magnetic ordering below 3.8 K. The released entropy is far from the expected value for a J = 5/2 system, implying that the magnetic state is partly disordered. Full magnetic polarization was reached in fields above 4 T, and the anomaly in the magnetic susceptibility can be fully suppressed in higher B fields. Hence, the suggested magnetic ground state is superparamagnetic. In order to better understand the magnetic nature of this compound, structural investigations were carried out. Raman and IR-spectroscopy as ...


Ionic Liquids As Crystallization Media: Weakly-Coordinating Anions Do Coordinate In 1∞[Eu(Otf)3(Ch3cn)3], Sifu Tang, Anja V. Mudring 2011 Iowa State University

Ionic Liquids As Crystallization Media: Weakly-Coordinating Anions Do Coordinate In 1∞[Eu(Otf)3(Ch3cn)3], Sifu Tang, Anja V. Mudring

Anja V. Mudring

Tris(acetonitrile)tris(trifluoromethanesulfonato)-europium(III), 1∞[Eu(OTf)3(CH3CN)3], is the first structurally characterized Ln(OTf)3-solvate where triflate is still in the coordination sphere of the Ln(III) cation and not substituted by solvate molecules. This fact is attributed to the unique crystallization conditions that an ionic liquid provides: 1∞[Eu(OTf)3(CH3CN)3] was obtained from a solution of europium(III) triflate, Eu(OTf)3, with acetonitrile in the ionic liquid [C4py][OTf] (1-butylpyridinium triflate). The crystal structure (triclinic, P1̅ (no. 2), a = 5.734(1) Å, b = 10.500(2) Å, c = 19 ...


Applications Of A General Random Walk Theory For Confined Diffusion, Elisa Calvo-Muñoz, Myvizhi Esai Selvan, Ruichang Xiong, Madhusudan Ojha, David Keffer, Donald Nicholson, Takeshi Egami 2010 University of Tennessee - Knoxville

Applications Of A General Random Walk Theory For Confined Diffusion, Elisa Calvo-Muñoz, Myvizhi Esai Selvan, Ruichang Xiong, Madhusudan Ojha, David Keffer, Donald Nicholson, Takeshi Egami

David Keffer

A general random walk theory for diffusion in the presence of nanoscale confinement is developed and applied. The random-walk theory contains two parameters describing confinement: a cage size and a cage-to-cage hopping probability. The theory captures the correct nonlinear dependence of the mean square displacement (MSD) on observation time for intermediate times. Because of its simplicity, the theory also requires modest computational requirements and is thus able to simulate systems with very low diffusivities for sufficiently long time to reach the infinite-time-limit regime where the Einstein relation can be used to extract the self-diffusivity. The theory is applied to three ...


Comparison Of Global And Sequential Methods For An Inverse Heat Transfer Problem, Bernard Marcos, Micael Boulet, Abdellah Ousegui, Christine Moresoli 2010 University of Sherbrooke

Comparison Of Global And Sequential Methods For An Inverse Heat Transfer Problem, Bernard Marcos, Micael Boulet, Abdellah Ousegui, Christine Moresoli

Abdellah Ousegui

This paper presents a comparison between global and sequential method to solve inverse 14 problem related to the baking process. The both methods aim to reconstruct the wall 15 temperature profile in the baking oven from the temperature of flux sensor (h-Monitor). 16 The global method solves the adjoint and sensitivity equations to compute the gradient 17 conjugate descent direction. The global method contains regularisation term that modifies 18 the computation of the gradient. The sequential method computes at each time step a 19 quasi-Newton descent direction taking into account a regularisation term. The sequential 20 method may consider one-step ...


On The Relationship Between The Structure Of Metal-Organic Frameworks And The Adsorption And Diffusion Of Hydrogen, Nethika Suraweera, Ruichang Xiong, J. P. Luna, Donald Nicholson, David Keffer 2010 University of Tennessee - Knoxville

On The Relationship Between The Structure Of Metal-Organic Frameworks And The Adsorption And Diffusion Of Hydrogen, Nethika Suraweera, Ruichang Xiong, J. P. Luna, Donald Nicholson, David Keffer

David Keffer

In this work, the adsorptive and diffusive behaviours of molecular hydrogen in 10 different isoreticular metal–organic frameworks (IRMOFs) are studied using molecular-level simulation. Hydrogen adsorption isotherms and heats of adsorption at 77 and 300 K were generated for 10 MOFs at low-pressure conditions (up to 10 bar) using Path Integral Grand Canonical Monte Carlo simulations. Self-diffusivities and activation energies for diffusion were generated using molecular dynamics simulation. Density distributions showing the location and the shape of the adsorption sites are also provided. Statistical correlations for all of the properties as a function of surface area (SA), accessible volume (AV ...


The First Lanthanide Telluride-Bromide: La3te4br, A Valence Compound, Markus Larres, Anja V. Mudring, Gerd Meyer 2010 Iowa State University

The First Lanthanide Telluride-Bromide: La3te4br, A Valence Compound, Markus Larres, Anja V. Mudring, Gerd Meyer

Gerd Meyer

The first ternary lanthanide telluride-bromide La3Te4Br was obtained from a mixture of LaTe and LaBr3 (in the presence of iridium) in a sealed tantalum container at elevated temperatures. The crystal structure (orthorhombic, Pnma, a = 1634.3(2), b = 435.0(1), c = 1426.6(2) pm, Z = 4, R1 (I0 > 2s(I0)) = 0.0349) is built from dicapped trigonal prisms of tellurium and bromine atoms surrounding lanthanum in two different ways. The dicapped trigonal prisms are connected via common edges to a threedimensional structure, in the same fashion as is known for the binary U3Te5. La3Te4Br is a valence compound ...


An Overview Of Technologies For Upgrading Of Biogas To Biomethane, Wojciech M. Budzianowski 2010 Wroclaw University of Technology

An Overview Of Technologies For Upgrading Of Biogas To Biomethane, Wojciech M. Budzianowski

Wojciech Budzianowski

The present contribution presents an overview of technologies available for upgrading of biogas to biomethane. Technologies under study include pressure swing adsorption (PSA), high-pressure water wash (HPWW), reactive absorption (RA), physical absorption (PA), membrane separation (MS) and cryogenic separation (CS).


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