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Experimental Study Of Micro-Vortex Generators At Mach 2.5, Adam J. Pierce 2010 University of Texas at Arlington

Experimental Study Of Micro-Vortex Generators At Mach 2.5, Adam J. Pierce

Mechanical and Aerospace Engineering Theses

Vortex generators are geometrical shapes that produce trailing vortices and are widely used for their ability to improve the flow quality over areas where flow separation may occur. Current topics involve utilizing the performance capabilities of vortex generators to influence the boundary layer under supersonic conditions. Such influence may provide an alternative means of reducing boundary layer flow separation and improving the overall quality of the flow in the boundary layer. This influence would maintain low drag in supersonic inlets and reduce the need for mechanical equipment used for boundary layer bleed leading to a reduction in aircraft weight and …


Computational Model For Transient And Steady State Analysis Of A 1-Dimensional Auto-Thermal Reformer, Srikanth Honavara Prasad 2010 University of Texas at Arlington

Computational Model For Transient And Steady State Analysis Of A 1-Dimensional Auto-Thermal Reformer, Srikanth Honavara Prasad

Mechanical and Aerospace Engineering Theses

This study presents a 1-dimensional mathematical model of steam reformer to be used with high temperature solid oxide fuel cell (SOFC). Steam reforming (SR) is widely used in industries to produce hydrogen from hydrocarbons. There are various physical processes associated with chemical reactions in the SR of methane such as mass, heat and momentum transport. In this study a one-dimensional SR reactor with built-in preheater and mixing chamber connected to fuel gas and steam reservoirs is modeled and analyzed. The main part of the reformer is a metallic tube with catalyst coating on the inner walls, and it can be …


Experimental Investigation Of Thermal Behaviour Of Air Foil Bearings, Ramesh Pandeshwara Sadashiva 2010 University of Texas at Arlington

Experimental Investigation Of Thermal Behaviour Of Air Foil Bearings, Ramesh Pandeshwara Sadashiva

Mechanical and Aerospace Engineering Theses

Micro-turbo machinery demands gas bearings to ensure compactness, lightweight and extreme temperature operation. Gas bearings with large stiffness and damping, and preferably of low cost, will enable successful commercial applications. One of the gas bearing which is used for experimental investigation is the Air foil bearing. Previously developed test rig has been modified and further developed for investigating this bearing at various temperatures and speeds. These gas bearings are self acting hydrodynamic air bearings which have been successfully applied to a variety of turbo machinery applications. This new modified test rig also has the capability to measure bearing torque during …


Applications Of Sensitivity Data To Eigensolution Reanalysis Of Modified Structures, Chandrashekhar Sureshchandra Patadia 2010 University of Texas at Arlington

Applications Of Sensitivity Data To Eigensolution Reanalysis Of Modified Structures, Chandrashekhar Sureshchandra Patadia

Mechanical and Aerospace Engineering Theses

Methods of computing eigensolution sensitivity have been known for a long time. Both exact and approximate methods are available in the literature. While eigenvalue sensitivity is used routinely in structural optimization with eigenvalue constraints, few application of eigenvector derivatives are reported in the literature. The objective of this thesis is to present an effective eigensolution reanalysis approach using first and second order eigenvector sensitivity data. In the proposed new approach, modes shapes and their derivatives are used as basis vector for eigensolution of the modified system. Comparison of numerical results with several existing eigensolution reanalysis methods shows the proposed algorithms …


Inverse Design Of Airfoils Using A Flexible Membrane Method, Kamon Thinsurat 2010 University of Texas at Arlington

Inverse Design Of Airfoils Using A Flexible Membrane Method, Kamon Thinsurat

Mechanical and Aerospace Engineering Theses

The Modified Garabedian Mc-Fadden (MGM) method is used to inversely design airfoils. The Finite Difference Method (FDM) for Non-Uniform Grids was developed to discretize the MGM equation for numerical solving. The Finite Difference Method (FDM) for Non-Uniform Grids has the advantage of being used flexibly with an unstructured grids airfoil. The commercial software FLUENT is being used as the flow solver. Several conditions are set in FLUENT such as subsonic inviscid flow, subsonic viscous flow, transonic inviscid flow, and transonic viscous flow to test the inverse design code for each condition. A moving grid program is used to create a …


Comprehensive Studies On Deep Soil Mixing And Lightweight Aggregates Applications To Mitigate Approach Slab Settlements, Ekarut Archeewa 2010 University of Texas at Arlington

Comprehensive Studies On Deep Soil Mixing And Lightweight Aggregates Applications To Mitigate Approach Slab Settlements, Ekarut Archeewa

Civil Engineering Dissertations

Bridge approach settlement is a common problem to the Transportation Departments nationwide. This uneven transition causes inconvenience to passengers and increases the cost of maintenance and repair of the distressed approach slabs. The Texas Department of Transportation spends millions of dollars annually to mitigate this problem across the state. The potential causes for this problem are numerous and purely site specific. Hence this problem may not have a unique solution. In this research, two methods were selected to mitigate the approach slab settlements. The first one is an improvement of ground foundation technique by using Deep Soil Mixing (DSM) columns …


Environmentally-Conscious Supply Chain Design In Support Of Food Security, Caroline C. Krejci, Benita M. Beamon 2010 University of Texas at Arlington

Environmentally-Conscious Supply Chain Design In Support Of Food Security, Caroline C. Krejci, Benita M. Beamon

Industrial, Manufacturing, and Systems Engineering Faculty Publications

This paper seeks to design food supply chain structures that can provide food security for every person in the world while supporting long-term environmental sustainability. In particular, we provide alternatives to the current food supply chain structure and analyze their potential for providing food security, in terms of productive capacity and long-term environmental sustainability. Given the current world population and expected continued growth, our analysis suggests that environmentally-sustainable food supply chains would be most effectively supported by local and organic agriculture, while maintaining a parallel industrial agricultural system. This hybrid system would adopt environmentally-sustainable principles whenever possible, seeking to increase …


Corporate Environmental Performance Rating Methodology, Arunapprakasini Sankaranarayanan 2010 University of Texas at Arlington

Corporate Environmental Performance Rating Methodology, Arunapprakasini Sankaranarayanan

Industrial, Manufacturing, and Systems Engineering Dissertations

Environmental issues are becoming increasingly important to all kinds of stakeholders and companies themselves, not only for cost avoidance due to regulations, laws, cleanup costs, litigations, controversies, etc, but to improve their intrinsic ethical worth as a company for better environmental sustainability. Off late, companies are increasingly investing in environmental initiatives for cost savings and to generate profits as well. However, since no clear definition of greenness exists, companies are finding it difficult to measure environmental performance as an internal and external benchmark and hence a sound performance measurement system with formal guidelines is yet to be in place. What …


Enriched Coal Ash Utilization For Augmenting Production Of Rice Under Acid Lateritic Soil, S. Karmakar, B.N. Mittra, B.C. Ghosh 2010 Department of Agronomy, Birsa Agricultural University, Ranchi, Jharkhand- 834 006, India.

Enriched Coal Ash Utilization For Augmenting Production Of Rice Under Acid Lateritic Soil, S. Karmakar, B.N. Mittra, B.C. Ghosh

Coal Combustion and Gasification Products Journal Archive

The use of industrial wastes such as fly ash (FA) or rice husk ash (RHA), along with paper factory sludge (PFS), farmyard manure (FYM), and chemical fertilizers (CF), under integrated nutrient management, was studied in acid lateritic soil on rice. Application of combined fertilization sources increased growth, yield attributes, and yield (up to 92.3 and 9.7% over control and CF, respectively) of wet season rice. The uptake of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, and Co was increased under combined fertilization sources. The study also indicated that such integrated plant nutrition system improved physico-chemical properties of soil …


Erosive Wear In Pipelines At Pneumatic Conveying Of Fine Silicon-Containing Materials, Viacheslav Y. Putilov, Vijay K. Agarwal, Irina V. Putilova 2010 Russia, Moscow Power Engineering Institute (MPEI), Informational and Analytical Center ‘‘Ecology in Power Engineering’’ , 111250 Moscow, Krasnokazarmennaya str.,14

Erosive Wear In Pipelines At Pneumatic Conveying Of Fine Silicon-Containing Materials, Viacheslav Y. Putilov, Vijay K. Agarwal, Irina V. Putilova

Coal Combustion and Gasification Products Journal Archive

Erosive wear is a major operational problem in conveying of hard abrasive bulk materials like silica sand, fly ash, coal dust, etc., in pneumatic conveying systems. Erosion results in emergency downtime of pneumatic conveying installations of ash and slag removal and dust-preparation systems at TPPs caused by holes in pipelines. That leads to worsening of technical, economic, and ecological parameters of thermal power plants as a whole. In MPEI, a model of estimating erosion of rectilinear and curvilinear sections of pneumatic conveying pipelines has been developed. To validate the estimating model developed in the MPEI, experimental investigations in the Indian …


Testing Of Interactions Between Coal Ash Leachates And Rock Materials For Mine Backfill Evaluations, Colin R. Ward, David French, Leanne Stephenson, Ken Riley, Zhongsheng Li 2010 School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney 2052, Australia, CSIRO Energy Technology, PMB 7 Menai 2234, Australia

Testing Of Interactions Between Coal Ash Leachates And Rock Materials For Mine Backfill Evaluations, Colin R. Ward, David French, Leanne Stephenson, Ken Riley, Zhongsheng Li

Coal Combustion and Gasification Products Journal Archive

A series of laboratory-based leaching tests has been developed to evaluate the chemical interaction between ash, water and different mine-site rock materials, as a basis for assessing the potential environmental impact of using coal ash as backfill in coal mines. Two different test protocols were used: a two-stage serial batch testing program in which leachate from representative ash samples were allowed to interact separately with relevant rock materials under laboratory conditions, and a single-stage mixed batch testing program in which 50:50 mixtures of the same ashes and rock samples were extracted with water following a similar procedure to leaching tests …


The Effect Of Drag-Reducing Additives On The Rheological Properties Of Fly Ash-Water Suspensions At Varying Temperature Environment, H.K. Naik, M.K. Mishra, Rao Karanam U.M. 2010 Department of Mining Engineering, National Institute of Technology, Rourkela, India

The Effect Of Drag-Reducing Additives On The Rheological Properties Of Fly Ash-Water Suspensions At Varying Temperature Environment, H.K. Naik, M.K. Mishra, Rao Karanam U.M.

Coal Combustion and Gasification Products Journal Archive

Fly ash transportation and disposal is a major problem in India. Presently fly ash is being transported as lean slurry in pipe lines requiring about 80 to 85% of water which, in turn, consumes more energy input. The objective of the present study is to evaluate the rheological characteristics of fly ash slurry at varying temperatures with and without an additive to facilitate smooth flow in the pipelines. Six fly ash slurry samples were prepared from the fly ash obtained from a thermal power plant situated in the southern part of India. The main constituents of the slurry were fly …


Waste Stabilization/Solidification (S/S) Of Eaf Dust Using Fly Ash-Based Geopolymers. Influence Of Carbonation On The Stabilized Solids, Y. Luna Galiano, C. Fernandez Pereira, J. Vale 2010 University of Seville, School of Engineering, Chemical and Environmental Engineering Department, Camino de los Descubrimientos s/n 41092, Seville, Spain

Waste Stabilization/Solidification (S/S) Of Eaf Dust Using Fly Ash-Based Geopolymers. Influence Of Carbonation On The Stabilized Solids, Y. Luna Galiano, C. Fernandez Pereira, J. Vale

Coal Combustion and Gasification Products Journal Archive

The effect of the curing in a carbonated ambient of the solids obtained after the stabilization/solidification (S/S) of metallurgical waste using geopolymerization technology is described in this paper. The electric arc furnace (EAF) dust to stabilize contains hazardous metals such as Pb, Cd, Cr, or Zn. Different geopolymeric agents such as potassium hydroxide, potassium silicate, metakaolin, and blast furnace slag have been used. Mixtures of EAF waste with these geopolymeric materials and class F fly ash as main silica and alumina source have been processed. Samples were submitted to an accelerated carbonation test. Compressive strength tests and different leaching tests …


Complexity Reduction For Vp6 To H.264 Transcoder Using Motion Vector Reuse, Jay R. Padia 2010 University of Texas at Arlington

Complexity Reduction For Vp6 To H.264 Transcoder Using Motion Vector Reuse, Jay R. Padia

Electrical Engineering Theses

VP6 is a video coding standard developed by On2 Technologies, Inc. It is the preferred codec for Macromedia Flash 8 video. VP6 gained importance with Macromedia Flash emerging as a widely adopted video streaming technology over the internet. H.264 is currently one of the most widely accepted video coding standards in the industry. It enables high quality video at low bitrates. Adobe adopted H.264 for its Flash video in August 2007. Adobe looks at adoption of H.264 as a major step towards enabling high quality video on the web. Hence there is increasing importance of techniques which can convert video …


Implementation And Performance Analysis Of 2-D Order 16 Integer Transforms In H.264/Avc And Avs-Video For High Definition Video Coding, Madhu Peringassery Krishnan 2010 University of Texas at Arlington

Implementation And Performance Analysis Of 2-D Order 16 Integer Transforms In H.264/Avc And Avs-Video For High Definition Video Coding, Madhu Peringassery Krishnan

Electrical Engineering Theses

H.264/AVC and AVS-video are two video coding standards that have a wide range of applications ranging from high-end professional camera and editing systems to low-end mobile applications. They strive to achieve maximum compression efficiency without compromising the quality of video. To this end many coding tools are defined in them. Transform coding is one among them. Transform coding represents the signal/image (that is currently in time/spatial domain) in another domain (transform domain), where most of the energy in signal/image is concentrated in a fewer number of coefficients. Thus the insignificant coefficients can be discarded after transform coding to achieve compression. …


Implementation Of Security Within Gen2 Protocol, Shesh Kumar Jagannatha 2010 University of Texas at Arlington

Implementation Of Security Within Gen2 Protocol, Shesh Kumar Jagannatha

Electrical Engineering Theses

In this thesis, I propose and evaluate several methods to integrate security within the identification process and memory access processes of the ISO 18000-6C (or GEN2) passive UHF radio frequency identification (RFID) protocol. The RFID Tags are promiscuous and they emit their unique identifiers in clear upon interrogation from the Reader. They do not have a mutual authentication process to validate the Readers and Tags, this allows eavesdropping, illicit reading from a malicious Reader and counterfeit Tags. GEN2 Tags are being integrated into driver's licenses and being used for border crossing identities; thus, there is a need to secure both …


Physics Behind Rfid Smart Card Security In Context Of Privacy, Kirti Chopra 2010 University of Texas at Arlington

Physics Behind Rfid Smart Card Security In Context Of Privacy, Kirti Chopra

Electrical Engineering Theses

In this thesis I prove that existing HF protocol is not secure. Lack of security in turn leads to violation of privacy.The unique ID on the HF RFID smart card can be sniffed by any eavesdropper. Not only eavesdropping, but cloning of the card is another significant problem that poses a privacy threat. An attacker can skim the information on a proximity card and clone it to use for his malicious purposes.RFID smart cards are now widely being used in credit cards,access system, transit system and many more such application. Tampering or malicious usage of data on aforementioned cards raises …


Analysis And Improvement Of Multiple Optimal Learning Factors For Feed-Forward Networks, Praveen Jesudhas 2010 University of Texas at Arlington

Analysis And Improvement Of Multiple Optimal Learning Factors For Feed-Forward Networks, Praveen Jesudhas

Electrical Engineering Theses

The effects of transforming the net function vector in the Multilayer Perceptron (MLP) are analyzed. The use of optimal diagonal transformation matrices on the net function vector is proved to be equivalent to training the MLP using multiple optimal learning factors (MOLF). A method for linearly compressing large ill-conditioned MOLF Hessian matrices into smaller well-conditioned ones is developed. This compression approach is shown to be equivalent to using several hidden units per learning factor. The technique is extended to large networks. In simulations, the proposed algorithm performs almost as well as the Levenberg Marquardt (LM) algorithm with the computational complexity …


An Fpga-Based System For Tracking Digital Information Transmitted Via Peer-To-Peer Protocols, Karl R. Schrader, Barry E. Mullins, Gilbert L. Peterson, Robert F. Mills 2010 Air Force Institute of Technology

An Fpga-Based System For Tracking Digital Information Transmitted Via Peer-To-Peer Protocols, Karl R. Schrader, Barry E. Mullins, Gilbert L. Peterson, Robert F. Mills

Faculty Publications

This paper presents a Field Programmable Gate Array (FPGA)-based tool designed to process file transfers using the BitTorrent Peer-to-Peer (P2P) protocol and VoIP phone calls made using the Session Initiation Protocol (SIP). The tool searches selected control messages in real time and compares the unique identifier of the shared file or phone number against a list of known contraband files or phone numbers. Results show the FPGA tool processes P2P packets of interest 92% faster than a software-only configuration and is 97.6% accurate at capturing and processing messages at a traffic load of 89.6 Mbps.


Nonlinear Circuit Analysis Via Perturbation Methods And Hardware Prototyping, Kofi Odame, P. E. Hasler 2010 Dartmouth College

Nonlinear Circuit Analysis Via Perturbation Methods And Hardware Prototyping, Kofi Odame, P. E. Hasler

Dartmouth Scholarship

Nonlinear signal processing is necessary in many emerging applications where form factor and power are at a premium. In order to make such complex computation feasible under these constraints, it is necessary to implement the signal processors as analog circuits. Since analog circuit design is largely based on a linear systems perspective, new tools are being introduced to circuit designers that allow them to understand and exploit circuit nonlinearity for useful processing. This paper discusses two such tools, which represent nonlinear circuit behavior in a graphical way, making it easy to develop a qualitative appreciation for the circuits under study.


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