Effects Of Tethering A Multistate Folding Protein To A Surface,
2011
Brigham Young University
Effects Of Tethering A Multistate Folding Protein To A Surface, Shuai Wei, Thomas A. Knotts Iv
Faculty Publications
Protein/surface interactions are important in a variety of fields and devices, yet fundamental understanding of the relevant phenomena remains fragmented due to resolution limitations of experimental techniques. Molecular simulation has provided useful answers, but such studies have focused on proteins that fold through a two-state process. This study uses simulation to show how surfaces can affect proteins which fold through a multistate process by investigating the folding mechanism of lysozyme (PDB ID: 7LZM). The results demonstrate that in the bulk 7LZM folds through a process with four stable states: the folded state, the unfolded state, and two stable intermediates. The …
Development Of A Phase Separation Model For A Biodiesel Reactor,
2011
University of Connecticut - Storrs
Development Of A Phase Separation Model For A Biodiesel Reactor, Lu Han
Honors Scholar Theses
The goal of this work is to establish a phase separation model for a biodiesel system, for the purpose of modeling a continuous flow multiphase biodiesel reactor. The Cahn-Hilliard theory is applied for a ternary system of two immiscible components and a third partially miscible component. The results of this work shows that phase field theory can be applied in phase modeling of a biodiesel system, and further investigations are required to develop a comprehensive biodiesel reactor model.
Comparison Of Entrainment Rate In Acrylonitrile Reactors Using Plant Data And Cfd Simulations,
2011
Ascend Performance Materials, LLC
Comparison Of Entrainment Rate In Acrylonitrile Reactors Using Plant Data And Cfd Simulations, S. Moffatt, S. Ramchandran, P. Zhao, K. Williams
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Accurate entrainment rates are important in fluidized bed reactors for several reasons, including determination of cyclone loadings and efficiencies, sizing of diplegs, and inputs to population balance models. Entrainment correlations exist in the literature and from other sources to predict entrainment rates from fluidized beds, but they can vary by orders of magnitude. In addition, many correlations do not take into account effects of internals which are present in many types of industrial reactors. A study was undertaken to better understand entrainment rates from Sohiotype acrylonitrile fluidized bed reactors containing catalyst classified as a Geldart type A powder. As part …
Cfd Simulation Of Co2 Sorption In A Circulating Fluidized Bed Using Deactivation Kinetic Model,
2011
Department of Chemical and Biological Engineering, Wanger Institute for Sustainable Energy Research (WISER), Illinois Institute of Technology
Cfd Simulation Of Co2 Sorption In A Circulating Fluidized Bed Using Deactivation Kinetic Model, Emadoddin Abbasi, Hamid Arastoopour
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
The Computational Fluid Dynamics (CFD) approach was used to simulate sorption of CO2 using solid sorbents in the riser section of a circulating fluidized bed. The simulation results were compared with the experimental data of Korea Institute for Energy Research (KIER) for continuous CO2 sorption using potassium carbonate in a circulating fluidized bed system.
Critical Evaluation Of Euler-Euler And Euler-Lagrangian Modelling Strategies In A 2-D Gas Fluidized Bed,
2011
Carlos III University of Madrid, Spain
Critical Evaluation Of Euler-Euler And Euler-Lagrangian Modelling Strategies In A 2-D Gas Fluidized Bed, F. Hernández-Jiménez, J. R. Third, A. Acosta-Iborra, C. R, Müller
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Two-phase granular systems are commonly encountered in industry, and fluidized beds are particularly important due to their excellent heat and mass transfer characteristics. Here, we critically evaluate the differences between two modelling strategies, Euler-Euler and Euler-Lagrangian models. Euler-Euler simulations were performed using MFIX and an in-house code was used for Euler-Lagrangian simulations. A 2D bed of width, height and transverse thickness of respectively, 0.2 m, 0.5 m and 0.01 m, served as a test case. The settled bed height was H0 = 0.2 m. Particles of density ρ = 1000 kg/m³ and diameter dp = 1.2 mm were fluidized with …
Particle-Fluid Flow Simulations Of An Fcc Regenerator,
2011
CPFD Software, LLC
Particle-Fluid Flow Simulations Of An Fcc Regenerator, Sam Clark
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
A particle-fluid flow simulation of a commercial-scale fluidized catalytic cracking unit has been conducted. The simulation was full-scale, three-dimensional, and with complex internal geometries. The focus of the computational model was to predict wear on internal structures. The geometry of the particle feed pipe was found to cause asymmetric flow of high-speed gas which led to significant wear.
Time-Resolved X-Ray Tomography Of A Fluidized Bed Of Geldart A Particles,
2011
Delft University of Technology
Time-Resolved X-Ray Tomography Of A Fluidized Bed Of Geldart A Particles, Robert Frank Mudde, Evert C. Wagner, J.R. Van Ommen, Q. Ricoux
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
This paper discusses the influence of fines on the size of bubbles moving through a 23 cm ID fluidized bed of Geldart A particles imaged with an X-ray Tomographic Scanner. In earlier work [1], the bubble distribution in a fluidized bed of Geldart B particles was shown. The current study using Geldart A particles is more challenging to the reconstruction algorithm, since there are more bubbles, and they are smaller in size. We study the influence of adding fines (i.e. particles <= 45 micron) to the system. When adding a mass fraction of fines of 24%, we find a decrease of the average bubble of 40% of the size for the original powder, in line with earlier results from pressure probes and optical probes [2]. We find that the entire distribution of the bubble sizes shifts to smaller values.
A Study Of Solids And Gas Mixing In A Partitioned Fluidized Bed,
2011
Korea Institute of Energy Research, Daejon
A Study Of Solids And Gas Mixing In A Partitioned Fluidized Bed, Young-Ju Seo, Solim Kang, Seung-Yong Lee, Young Cheol Park, Ho-Jung Ryu, Gyoung Tae Jin, Jong-Ho Moon
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
A partitioned fluidized bed gasifier has been developed for improving coal gasification performance. The basic concept is to divide a fluidized bed into two parts, a gasifier and a combustor, by a partition. Char is burnt in the combustor and generated heat is supplied to the gasifier by solid mixing. Therefore, solid mixing should be maximized whereas gas mixing between syngas and the combusted gas should be minimized. In this study, gas and solid mixing behaviors were verified in cold model acrylic beds. For monitoring solid mixing behavior, transient temperature trends in the beds were analyzed. A heat source and …
Cfd Modeling Of Fluidized Bed Reactor For The Synthesis Of Dimethyl Ether,
2011
RTI International
Cfd Modeling Of Fluidized Bed Reactor For The Synthesis Of Dimethyl Ether, Ranjeeth Kalluri, Nandita Akunuri, Aqil Jamal, Raghubir Gupta
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
The syngas-to-DME reaction is highly exothermic, and the catalyst temperature window is very narrow. The fluidized-bed reactor is, therefore, an ideal choice to carry out these reactions. RTI is developing a circulating fluidized bed design for DME synthesis. This paper discusses a two-phase CFD model and optimization of the solids circulation rate.
A New Approach For Modeling Of A Fluidized Bed By Cfd-Dem,
2011
University of Tehran
A New Approach For Modeling Of A Fluidized Bed By Cfd-Dem, Shayan Karimipour, Navid Mostoufi, Rahmat Sotudeh-Gharebagh, H. Chizari
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Numerical studies of 3D cylindrical fluidized bed by means of combined computational fluid dynamics (CFD) and discrete element method (DEM) were carried out. For motion of particles, Newton's second law and 3D compressible Navier-Stokes equations in generalized curvilinear coordinates in its conservative form were used. Navier-Stokes equations were solved with high order compact finite difference scheme by fully implicit flux decomposition method. Non-reflecting boundary conditions (NRBC) were used for the outflow boundary. The convergence of this method, especially at high Reynolds number, is significantly better than the SIMPLE method.
Description Of Pressure Fluctuations In A Circulating Fluidized Bed By Statistical Analysis,
2011
Sasol Technology, South Africa
Description Of Pressure Fluctuations In A Circulating Fluidized Bed By Statistical Analysis, Adam Luckos, Roelof Coetzer, Andre Mostert
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
In this paper we evaluate different methods for statistically analyzing the variability in pressure fluctuations measured at three locations in an 80-mm-ID, 5-m-tall CFB model operated with natural rutile particles and air at ambient conditions. The methods evaluated are the Shannon entropy, Fischer information matrix together with kernel density estimation, and an estimation of the magnitude of the pressure amplitudes. The accuracy of the different methods is estimated by the bootstrap method. We illustrate how informative statistics from these methods can be used to quantify the effect of the process variables on fluidization at different bed locations. Depending on the …
Characterization Of Fluidization And Mixing Of Binary Mixtures Containing Biomass At Low Velocities Through Analyzing Local Pressure Fluctuations,
2011
École Polytechnique, Canada
Characterization Of Fluidization And Mixing Of Binary Mixtures Containing Biomass At Low Velocities Through Analyzing Local Pressure Fluctuations, Farzam Fotovat, Jaber Shabanian, Jamal Chaouki, Jeffrey Bergthorson
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
To judge qualitatively the effect of biomass properties on its fluidizability and mixing tendency with sand particles at low fluidization velocities, local pressure gradients in the top and bottom of the bed were compared for all investigated systems. It was found that changing the mass fraction and the size of biomass impacted the onset of bubbling and the size of bubbles across the bed, which, in turn, affected the mixing/segregation of the bed content.
Dynamics Of Gas-Solids Fluidized Beds Through Pressure Fluctuations: A Brief Examination Of Methods Of Analysis,
2011
Chalmers University of Technology, Sweden
Dynamics Of Gas-Solids Fluidized Beds Through Pressure Fluctuations: A Brief Examination Of Methods Of Analysis, Srdjan Sasic, Marc-Oliver Coppens, Filip Johnsson, J. Ruud Van Ommen, John Van Der Schaaf, Stefan Gheorghiu
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
This paper revisits and critically examines a number of methods used for analysis of in-bed pressure signals recorded in gas-solid fluidized beds. The goal is to obtain information on the time scales of dominant phenomena present in the pressure time series of four fluidization regimes. It is demonstrated that the average cycle time represents an effective alternative to spectral analysis. In addition, we give evidence that the average cycle time yields equivalent information as some of the advanced methods of non-linear analysis (e.g. the Kolmogorov entropy). Finally, by using wavelets and wavelet packets, we show how to obtain an accurate …
Dynamic Characteristics Of Bubbling And Turbulent Fluidization Using Hurst Analysis Technique,
2011
University of Tehran, Iran
Dynamic Characteristics Of Bubbling And Turbulent Fluidization Using Hurst Analysis Technique, H. Azizpour, Navid Mostoufi, Reza Zarghami, Rahmat Sotudeh-Gharebagh
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
A non-intrusive vibration monitoring technique was used to study the flow behavior in a fluidized bed. This technique has several advantages compared to other techniques, such as pressure probes and optical fiber probes which may influence the measurement because they are intrusive. Experiments were conducted in a 15 cm diameter by 2 m tall fluidized bed using 470 micron sand particles. Auto correlation functions, mutual information function and Hurst exponent analyses were used to analyze the fluidized bed hydrodynamics near the transition point from bubbling to turbulent fluidization regime. These methods were able to detect the regime transition point using …
Dem Study Of Fluidized Bed Dynamics During Particle Coating In A Spouted Bed Apparatus,
2011
Hamburg University of Technology
Dem Study Of Fluidized Bed Dynamics During Particle Coating In A Spouted Bed Apparatus, Sergiy Antonyuk, Stefan Heinrich, A. Ershova
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
A novel process for coating of spherical aerogel particles in a spouted bed is suggested. Using Discrete Element Method the influence of the density and restitution coefficient of experimentally coated aerogels on the fluidized bed dynamics in the developed apparatus was described.
Ecvt Imaging Of 3-D Flow Structures And Solids Concentration Distributions In A Riser And A Bend Of A Gas-Solid Circulating Fluidized Bed,
2011
William G. Lowrie Department of Chemical and Biomolecular Engineering The Ohio State University
Ecvt Imaging Of 3-D Flow Structures And Solids Concentration Distributions In A Riser And A Bend Of A Gas-Solid Circulating Fluidized Bed, Fei Wang, Qussai Marashdeh, Liang Shih Fan
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Experimental studies using electrical capacitance volume tomography (ECVT) are conducted to examine gas-solid flows in a riser and a bend of a 0.05 m (2 in) ID gas-solid circulating fluidized bed (CFB) system. The quantitative measurements using ECVT are made that illustrate a three-dimensional symmetric core-annulus structure in the riser and a non-centro-symmetric core-annulus structure in the bend. Results on the volume solids holdup distributions in the riser and in the bend at various operating conditions are also obtained.
Sulfur Uptake By Limestone-Based Sorbent Particles In Cfbc: The Influence Of Attrition/Fragmentation On Sorbent Inventory And Particle Size Distribution,
2011
Università degli Studi di Napoli Federico II, Italy
Sulfur Uptake By Limestone-Based Sorbent Particles In Cfbc: The Influence Of Attrition/Fragmentation On Sorbent Inventory And Particle Size Distribution, Fabio Montagnaro, Piero Salatino, Fabrizio Scala, Massimo Urciuolo
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
This paper presents a population balance model aiming at the prediction of sorbent inventory and particle size distribution establishing at steady state in the bed of an air-blown CFBC fuelled with a sulphur-bearing solid fuel. The core of the model is represented by population balance equations on sorbent particles which embody terms expressing the extent/rate of sorbent attrition/fragmentation. The effect of the progress of sulphation on attrition and fragmentation is taken into account by selection of appropriate constitutive equations. Model results are presented and discussed with the aim of clarifying the influence of particle attrition/fragmentation on sorbent inventory and particle …
Putting Structure Into Fluidized Bed – From Concept To Industrial Applications,
2011
(FLOTU), Department of Chemical Engineering, Tsinghua University
Putting Structure Into Fluidized Bed – From Concept To Industrial Applications, Fei Wei, Qiang Zhang, Guohua Luo, Weizhong Qian, Yao Wang
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
Structures of particles, particle agglomerates, distributors, and internals have significantly influence on hydrodynamics and transfer behaviors of the dense gas-solid fluidized bed. For nanomaterial production, the particle surface and their agglomerated structures directly influence the fluidization behaviors; while for coal to chemical process, the distributors, internals play an important role in regime transient, and hydrodynamics. Carbon nanotubes mass production, coal to chemicals process. and fuel production were employed as examples to describe the concept of putting structures into fluidized bed, and then to put these structures into industrial applications.
Study Of Standpipe And Loop Seal Behavior In A Circulating Fluidized Bed For Geldart B Particles,
2011
Institute of Combustion and Power Plan Technology, University of Stuttgart
Study Of Standpipe And Loop Seal Behavior In A Circulating Fluidized Bed For Geldart B Particles, Heiko Dieter, Alexander Charitos, Ajay R. Bidwe, An Wei, Mariusz Zieba
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
The loop seal aeration effect on the supply side has been studied through small scale CFB experimentation. Parameters affected include inventory allocation and entrainment. The gas velocity in the standpipe is influenced by loop seal aeration and riser velocity. Variation in slugging behavior above and below solid downflow velocity of 0.025 m/s is analyzed and discussed here.
Observation Of Flow Regime Transition In A Cfb Riser Using An Ldv,
2011
National Energy Technology Laboratory
Observation Of Flow Regime Transition In A Cfb Riser Using An Ldv, Paul C. Yue, Joseph Mei, Lawrence J. Shadle
10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10
The solids flow in a circulating fluidized bed (CFB) riser is often described to have a core-annular structure. For a given superficial gas velocity, at the initial introduction of solids into a riser a flow structure of dilute upflow regime exists. Continuing to increase the solids flow in the riser transitions the flow structure to the core-annular flow regime. However, with further increase of solids flow a condition is reached, depending on the superficial gas velocity, where all the solids across the riser cross section flow upwards, even those at the wall. When the solids flux, solids fraction and gas …
