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Bed Height And Material Density Effects On Fluidized Bed Hydrodynamics, David Roberto Escudero 2010 Iowa State University

Bed Height And Material Density Effects On Fluidized Bed Hydrodynamics, David Roberto Escudero

Graduate Theses and Dissertations

Fluidized bed reactors are important assets of many industrial applications. Understanding how a fluidized bed as a multiphase flow system operates will improve its capabilities and operations. Minimum fluidization velocity and local gas holdup are important parameters used to characterize the hydrodynamic behavior of a material inside the fluidized bed. Due to the opaque nature of a fluidized bed system, noninvasive X-ray techniques are often used to visualize and obtain valuable data regarding the internal flow structures of the fluidized material.

This research determines how fluidized bed hydrodynamics are influenced by different experimental conditions. X-ray computed tomography imaging is applied ...


Audio Watermarking Using Transformation Techniques, Rajkiran Ravula 2010 Louisiana State University and Agricultural and Mechanical College

Audio Watermarking Using Transformation Techniques, Rajkiran Ravula

LSU Master's Theses

Watermarking is a technique, which is used in protecting digital information like images, videos and audio as it provides copyrights and ownership. Audio watermarking is more challenging than image watermarking due to the dynamic supremacy of hearing capacity over the visual field. This thesis attempts to solve the quantization based audio watermarking technique based on both the Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT). The underlying system involves the statistical characteristics of the signal. This study considers different wavelet filters and quantization techniques. A comparison is performed on diverge algorithms and audio signals to help examine the performance ...


Integrating Bioprocesses Into Industrial Complexes For Sustainable Development, Debalina Sengupta 2010 Louisiana State University and Agricultural and Mechanical College

Integrating Bioprocesses Into Industrial Complexes For Sustainable Development, Debalina Sengupta

LSU Doctoral Dissertations

The objective of this research is to propose, develop and demonstrate a methodology for the optimal integration of bioprocesses in an existing chemical production complex. Chemical complex optimization is determining the optimal configuration of chemical plants in a superstructure of possible plants based on economic, environmental and sustainable criteria objective function (triple bottomline) and solves a mixed integer non linear programming problem. This research demonstrated the transition of production of chemicals from non-renewable to renewable feedstock. A conceptual design of biochemical processes was converted to five industrial scale designs in Aspen HYSYS® process simulator. Fourteen input-output block models were created ...


Understanding The Product Distribution From Biomass Fast Pyrolysis, Pushkaraj Ramchandra Patwardhan 2010 Iowa State University

Understanding The Product Distribution From Biomass Fast Pyrolysis, Pushkaraj Ramchandra Patwardhan

Graduate Theses and Dissertations

Fast pyrolysis of biomass is an attractive route to transform solid biomass into a liquid bio-oil, which has been envisioned as a renewable substitute for crude oil. However, lack of fundamental understanding of the pyrolysis process poses a significant challenge in developing cost-effective pyrolysis based technologies for producing transportation fuels. The fundamental knowledge of pyrolysis pathways, product distribution and underlying mechanisms will have a direct and significant impact on the reactor design, strategic operation and kinetic modeling of the pyrolysis process. However, this knowledge has remained obscure due to the complexity of the pyrolysis process and lack of well established ...


Estimation, Training, And Effect Of Timing Offsets In Distributed Cooperative Networks, Hani Mehrpouyan, Steven D. Blostein 2010 Boise State University

Estimation, Training, And Effect Of Timing Offsets In Distributed Cooperative Networks, Hani Mehrpouyan, Steven D. Blostein

Hani Mehrpouyan

Successful collaboration in cooperative networks requires accurate estimation of multiple timing offsets. When combined with signal processing algorithms, the estimated timing offsets can be applied to mitigate the resulting inter-symbol interference (ISI). This paper seeks to address timing synchronization in distributed multi-relay amplify-and-forward (AF) and decode-andforward (DF) relaying networks, where timing offset estimation using a training sequence is analyzed. First, training sequence design guidelines are presented that are shown to result in improved estimation performance. Next, two iterative estimators are derived that can determine multiple timing offsets at the destination. The proposed estimators have a considerably lower computational complexity while ...


Influence Of Post-Consumer Recycled Asphalt Shingles On Hot Mix Asphalt Containing Fractionated Recycled Asphalt Pavement, Andrew Aaron Cascione 2010 Iowa State University

Influence Of Post-Consumer Recycled Asphalt Shingles On Hot Mix Asphalt Containing Fractionated Recycled Asphalt Pavement, Andrew Aaron Cascione

Graduate Theses and Dissertations

As the cost of construction materials continue to rise and place financial constraints on transportation agencies, engineers are looking for sustainable methods that minimize construction costs and optimize the selection of materials used in asphalt pavements. Two methods that are beginning to receive considerable attention for highway construction are adding post-consumer recycled asphalt shingles (RAS) to hot mix asphalt (HMA) and increasing the percentage of recycled asphalt pavement being added to HMA through the process of fractionation.

The objective of this research is to characterize the effects of post-consumer RAS on the laboratory performance of HMA and its compatibility with ...


Efficient Methods For Solving Boundary Integral Equation In Diffusive Scalar Problem And Eddy Current Nondestructive Evaluation, Ming Yang 2010 Iowa State University

Efficient Methods For Solving Boundary Integral Equation In Diffusive Scalar Problem And Eddy Current Nondestructive Evaluation, Ming Yang

Graduate Theses and Dissertations

Eddy current nondestructive evaluation (NDE) of airframe structures involves the detection of electromagnetic field irregularities due to non-conducting inhomogeneities in an electrically conducting material. Usually, the eddy current NDE problem can be formulated by the boundary integral equations (BIE) and discretized into matrix equations by the method of moments (MoM) or the boundary element method (BEM). The fast multipole method (FMM) is a well-established and effective method for accelerating numerical solutions of the matrix equations. Accelerated by the FMM, the BIE method can now solve large-scale electromagnetic wave propagation and diffusion problems. The traditional BIE method requires O(N2 ...


Solid-State Compatibilization Of Immiscible Polymer Blends: Cryogenic Milling And Solid-State Shear Pulverization, Marc Frederick Henry 2010 Bucknell University

Solid-State Compatibilization Of Immiscible Polymer Blends: Cryogenic Milling And Solid-State Shear Pulverization, Marc Frederick Henry

Master’s Theses

The blending of common polymers allows for the rapid and facile synthesis of new materials with highly tunable properties at a fraction of the costs of new monomer development and synthesis. Most blends of polymers, however, are completely immiscible and separate into distinct phases with minimal phase interaction, severelydegrading the performance of the material. Cross-phase interactions and property enhancement can be achieved with these blends through reactive processing or compatibilizer addition. A new class of blend compatibilization relies on the mechanochemical reactions between polymer chains via solid-state, high energy processing. Two contrasting mechanochemical processing techniques are explored in this thesis ...


Modified Sheet Pile Abutments For Low Volume Road Bridges, Ryan Richard Evans 2010 Iowa State University

Modified Sheet Pile Abutments For Low Volume Road Bridges, Ryan Richard Evans

Graduate Theses and Dissertations

Iowa Highway Research Board Project TR-568 was initiated in January 2007 to investigate the use of steel sheet piling as an alternative foundation component for Low Volume Road (LVR) bridges. A total of 14 different sites were initially investigated in several counties as potential candidates for the construction of demonstration projects utilizing steel sheet pile abutments. Based on site conditions, three sites were selected for demonstration projects; these are located in Black Hawk, Boone, and Tama Counties. Each of the demonstration projects utilizes a different experimental abutment system.

Steel sheet piling, typically used for retaining structures in the United States ...


Transfer Operator-Based Approach For Domain Of Attraction Computation And Experimental Data Analysis, Kai Wang 2010 Iowa State University

Transfer Operator-Based Approach For Domain Of Attraction Computation And Experimental Data Analysis, Kai Wang

Graduate Theses and Dissertations

We present novel transfer operator-based methods for domain of attraction computation and experimental data analysis of nonlinear systems. The problem of domain of attraction (DA) computation is of great practical interest with applications in various engineering and physical systems such as power system, chemical processes, aircraft control, and biological systems. We propose linear transfer operator-based set-oriented numerical method for DA computation of nonlinear systems. The proposed method overcomes some of the shortcoming of the existing methods of DA computation; in particular the proposed method can be used for DA computation of non-polynomial vector fields and for systems with non-equilibrium dynamics ...


A General Approach Towards The Synthesis Of Amido-Functionalized Biodegradable Polyesters, Joseph Russell 2010 Bucknell University

A General Approach Towards The Synthesis Of Amido-Functionalized Biodegradable Polyesters, Joseph Russell

Master’s Theses

The thesis presented here describes methodologies to produce pendant group functionalized polyesters from amido-functionalized α-hydroxy acids. The synthetic methods used to produce the functionalized α-hydroxy acids are compatible with a wide array of functional groups, making this technique highly versatile. The synthesis of functionalized polyesters was investigated to develop polymers with properties that may improve the capabilities of existing biodegradable polyesters for applications in controlled release pharmaceuticals. Chemically modified a-hydroxy acids were synthesized by reacting glyoxylic acid with a primary or secondary amide. To demonstrate the utility of this reaction, fourstructurally dissimilar amide substituents were examined including 2-pyrrolidione ...


Bounds On Timing Jitter Estimation In Cooperative Networks, Hani Mehrpouyan, Steven Blostein 2010 Queen's University

Bounds On Timing Jitter Estimation In Cooperative Networks, Hani Mehrpouyan, Steven Blostein

Hani Mehrpouyan

Successful collaboration and resource sharing in cooperative networks require accurate estimation of multiple timing jitters. When combined with signal processing algorithms the estimated timing jitters can be applied to mitigate the resulting inter-symbol interference (ISI) and improve performance. In this paper we seek to derive the Cramer-Rao lower bounds (CRLB) for timing jitter estimation in distributed cooperative networks. In addition to being a benchmark for judging the performance of timing jitter estimators, the CRLBs can be applied to determine the effect of the choices of training sequence and cooperative protocol on timing jitter estimation.


Synchronization In Cooperative Networks: Estimation Of Multiple Carrier Frequency Offsets, Hani Mehrpouyan, Steven Blostein 2010 Boise State University

Synchronization In Cooperative Networks: Estimation Of Multiple Carrier Frequency Offsets, Hani Mehrpouyan, Steven Blostein

Hani Mehrpouyan

The distributed nature of cooperative networks may result in multiple carrier frequency offsets (CFOs), which make the channel time-varying and overshadow the performance gainspromised by collaborative communications. However, much of the analysis in the area of cooperative communications assumes perfect synchronization. This paper seeks to address frequency synchronization in cooperative communication systems, where CFO estimation using a training sequence is analyzed. The Cramer-Rao lower bound (CRLB) for various cooperative protocols is derived. In the next step, we propose two computationally efficient iterative estimators based on the MUltiple SIgnal Characterization (MUSIC) algorithm, that can estimate the CFOs from all the relays ...


Numerical Investigation Of Mechanical Durability In Polymer Electrolyte Membrane Fuel Cells, Ahmet Kusoglu, Michael H. Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson 2010 University of Delaware

Numerical Investigation Of Mechanical Durability In Polymer Electrolyte Membrane Fuel Cells, Ahmet Kusoglu, Michael H. Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson

Mechanical Engineering Faculty Publications

The relationship between the mechanical behavior and water transport in the membrane electrode assembly (MEA) is numerically investigated. Swelling plays a key role in the mechanical response of the MEA during fuel cell operation because swelling can be directly linked to the development of stresses. Thus, in the model introduced here, the stresses and the water distribution are coupled. Two membranes are studied: unreinforced perfluorosulfonic acid (PFSA) and an experimental reinforced composite membrane. The results suggest that open-circuit voltage operations lead to a uniform distribution of stresses and plastic deformation, whereas under current-load operation, the stresses and the plastic deformation ...


Development Of A Family Of High Strength Low Carbon Microalloyed Ultra-Thin Cast Strip Products Produced By The Castrip® Process, Chris R. Killmore, Kristin R. Carpenter, Harold R. Kaul, James G. Williams, Daniel G. Edelman, Peter C. Campbell, Walter N. Blejde 2010 BlueScope Steel

Development Of A Family Of High Strength Low Carbon Microalloyed Ultra-Thin Cast Strip Products Produced By The Castrip® Process, Chris R. Killmore, Kristin R. Carpenter, Harold R. Kaul, James G. Williams, Daniel G. Edelman, Peter C. Campbell, Walter N. Blejde

Faculty of Engineering and Information Sciences - Papers: Part B

The manufacture of high strength strip products in strip thicknesses less than 1.5mm is very challenging for the conventional hot and cold rolled processing routes. A range of Nb and Nb/V microalloyed steels have been successfully strip cast by the CASTRIP process enabling the development of a range of high strength Ultra-Thin Cast Strip (UCS) products. It was found that the CASTRIP process fully exploits the strengthening potential of the low C-Mn-Nb-(V) alloy design system. Substantial strengthening by microstructural hardening was provided by Nb. Retention of Nb and V in solid solution in hot rolled coils enabled ...


The Mechanical And The Electrical Properties Of Conducting Polypyrrole Fibers, Javad Foroughi, Shaban R. Ghorbani, Germanas Peleckis, Geoffrey M. Spinks, Gordon G. Wallace, Xiaolin Wang, S X. Dou 2010 University of Wollongong

The Mechanical And The Electrical Properties Of Conducting Polypyrrole Fibers, Javad Foroughi, Shaban R. Ghorbani, Germanas Peleckis, Geoffrey M. Spinks, Gordon G. Wallace, Xiaolin Wang, S X. Dou

Australian Institute for Innovative Materials - Papers

The mechanical and the electrical properties of polypyrrole (PPy) fibers and electrochemically deposited PPy films were studied. It was found that the PPy fibers showed a significantly higher strength than the PPy films due to better orientation of the molecular structure. The electrochemically prepared PPy films had a higher electrical conductivity than that of the fibers at high temperature. At low temperature, the PPy fibers showed the higher conductivity. The conductivity results were analyzed in the frame of the three-dimensional variable range hopping model. The results showed that at room temperature the average hopping distance for the fibers was about ...


The Manifestation Of Stopping Sets And Absorbing Sets As Deviations On The Computation Trees Of Ldpc Codes, Eric T. Psota, Lance C. Perez 2010 University of Nebraska-Lincoln

The Manifestation Of Stopping Sets And Absorbing Sets As Deviations On The Computation Trees Of Ldpc Codes, Eric T. Psota, Lance C. Perez

Faculty Publications from the Department of Electrical and Computer Engineering

The error mechanisms of iterative message-passing decoders for low-density parity-check codes are studied. A tutorial review is given of the various graphical structures, including trapping sets, stopping sets, and absorbing sets that are frequently used to characterize the errors observed in simulations of iterative decoding of low-density parity-check codes. The connections between trapping sets and deviations on computation trees are explored in depth using the notion of problematic trapping sets in order to bridge the experimental and analytic approaches to these error mechanisms. A new iterative algorithm for finding low-weight problematic trapping sets is presented and shown to be capable ...


Mimo Self-Encoded Spread Spectrum With Iterative Detection Over Rayleigh Fading Channels, Shichuan Ma, Lim Nguyen, Won Mee Jang, Yaoqing (Lamar) Yang 2010 University of Nebraska - Lincoln

Mimo Self-Encoded Spread Spectrum With Iterative Detection Over Rayleigh Fading Channels, Shichuan Ma, Lim Nguyen, Won Mee Jang, Yaoqing (Lamar) Yang

Faculty Publications from the Department of Electrical and Computer Engineering

Self-encoded spread spectrum (SESS) is a novel communication technique that derives its spreading code from the randomness of the source stream rather than using conventional pseudorandom noise (PN) code. In this paper, we propose to incorporate SESS in multiple-input multiple-output (MIMO) systems as a means to combat against fading effects in wireless channels. Orthogonal space-time block-coded MIMO technique is employed to achieve spatial diversity, and the inherent temporal diversity in SESS modulation is exploited with iterative detection. Simulation results demonstrate that MIMO-SESS can effectively mitigate the channel fading effect such that the system can achieve a bit error rate of ...


Investigation Of The Design Of A Bistable Micro-Chemical-Mechanical Device Utilizing Lateral Buckling, Susan Lyn Barnes 2010 Bucknell University

Investigation Of The Design Of A Bistable Micro-Chemical-Mechanical Device Utilizing Lateral Buckling, Susan Lyn Barnes

Honors Theses

The Gracias Laboratory at Johns Hopkins University has developed microgrippers which utilize chemically-actuated joints to be used in micro-surgery. These grippers, however, take up to thirty minutes to close fully when activated biochemicals in the human body. This is very problematic and could limit the use of the devices in surgery. It is the goal of this research to develop a gripper that uses theGracias Laboratory's existing joints in conjunction with mechanical components to decrease the closing time. The purpose of including the mechanical components is to induce a state of instability at which time a small perturbation would ...


Molecular Modeling Of Energetic Materials And Chemical Warfare Agents, Nandhini Sokkalingam 2010 Wayne State University

Molecular Modeling Of Energetic Materials And Chemical Warfare Agents, Nandhini Sokkalingam

Wayne State University Dissertations

Contamination of military sites by energetic materials and chemical warfare agents is a growing problem. To avoid health hazards associated with these compounds, it is necessary to decontaminate or remediate the contaminated sites. Effective decontamination requires knowledge of environmental fate of contaminants and the appropriate remediation methodologies. While the fate of chemical warfare agents are well studied, the impact of certain energetic materials in the environment is relatively unknown. So the current focus is determining environmental fate of Insensitive Munitions (IM) which are energetic materials that have low shock sensitivity and high thermal stability and developing detection schemes for identifying ...


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