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Finite Element Analysis Of A Nose Gear During Landing, Thoai D. Nguyen 2010 University of North Florida

Finite Element Analysis Of A Nose Gear During Landing, Thoai D. Nguyen

UNF Graduate Theses and Dissertations

Nose gear failure is a high concern in the aviation industries. According to the Federal Aviation Administration reports, 55% of aircraft failures occur during takeoff and landing while 45% of failures occur during flight. The objective of this thesis is to determine the stress behavior and the displacement of a nose gear of an aircraft during landing using structural finite element analysis. The nose gear was first modeled using computer-aided design software and then imported into finite element software. The external forces were determined analytically and the interactions between components were carefully modeled using contact analysis. The tire was modeled ...


Optimal Design Of Trusses With Geometric Imperfections, Mehdi Jalalpour, Takeru Igusa, James K. Guest 2010 Cleveland State University

Optimal Design Of Trusses With Geometric Imperfections, Mehdi Jalalpour, Takeru Igusa, James K. Guest

Civil and Environmental Engineering Faculty Publications

The present paper focuses on optimization of trusses that have randomness in geometry that may arise from fabrication errors. The analysis herein is a generalization of a perturbation approach to topology optimization under geometric uncertainties. The main novelty in the present paper is in the consideration of potential buckling due to misaligned structural members. The paper begins with a brief review of the aforementioned perturbation approach, then proceeds with the analysis of the nonlinear effects of geometric imperfection. The paper concludes with some numerical examples.


A New Class Of Attacks On Time Series Data Mining, Ye Zhu, Yongjian Fu, Huirong Fu 2010 Cleveland State University

A New Class Of Attacks On Time Series Data Mining, Ye Zhu, Yongjian Fu, Huirong Fu

Electrical Engineering & Computer Science Faculty Publications

Traditional research on preserving privacy in data mining focuses on time-invariant privacy issues. With the emergence of time series data mining, traditional snapshot-based privacy issues need to be extended to be multi-dimensional with the addition of time dimension. We find current techniques to preserve privacy in data mining are not effective in preserving time-domain privacy. We present the data flow separation attack on privacy in time series data mining, which is based on blind source separation techniques from statistical signal processing. Our experiments with real data show that this attack is effective. By combining the data flow separation method and ...


Delay, Cost And Infrastructure Tradeoff Of Epidemic Routing In Mobile Sensor Networks, Shan Zhou, Lei Ying, Srikanta Tirthapura 2010 Iowa State University

Delay, Cost And Infrastructure Tradeoff Of Epidemic Routing In Mobile Sensor Networks, Shan Zhou, Lei Ying, Srikanta Tirthapura

Electrical and Computer Engineering Conference Papers, Posters and Presentations

This paper studies the delay, cost and infrastructure tradeoff of epidemic routing in mobile sensor networks. We consider a mobile sensor network with M mobiles and B static base stations. The mobile sensors collect information when moving around and need to report the information to the base stations. Three different epidemic routing schemes --- target epidemic routing, uncontrolled epidemic routing and controlled epidemic routing --- are analyzed in this paper. For each of the three schemes, we characterize the scaling behaviors of the delay, which is defined to be the average number of time slots required to deliver a message, and the ...


Reconfiguration Of Power Networks Based On Graph-Theoretic Algorithms, Juan Li 2010 Iowa State University

Reconfiguration Of Power Networks Based On Graph-Theoretic Algorithms, Juan Li

Graduate Theses and Dissertations

The intentional area partitioning and automated distribution system restoration are two important "Smart Grid" technologies to enhance the robustness of a power network and improve the system reliability. In this dissertation, the research work is focused on deriving and implementing efficient graph-theoretic algorithms to analyze and solve such two real-world problems in power systems as follows.

In response to disturbances, a self-healing system reconfiguration that splits a power network into self-sufficient islands can stop the propagation of disturbances and avoid cascading events. An area partitioning algorithm that minimizes both real and reactive power imbalance between generation and load within islands ...


Creating A Responsive, Real-Time, Malleable Environment For Dancers, Valerie Jane Williams 2010 Iowa State University

Creating A Responsive, Real-Time, Malleable Environment For Dancers, Valerie Jane Williams

Graduate Theses and Dissertations

The traditional choreographer/dancer paradigm uses the dancer as a tool of the choreographer. By contrast, a real-time responsive environment, consisting of rendered video and motion-generated video and sound allows the dancer to become a co-creator in both the rehearsal process and the performances. A malleable visual and sonic environment means that the dancer's relation to their environment becomes a self-directed mixture of expressive and responsive elements. This results in a more authentic experience, as the dancer can use his or her movement to not just alter the environment, but use that environment to accompany the dancer rather than ...


On The Interaction Of An Eddy Current Coil With A Right-Angled Conductive Wedge, John R. Bowler, Theodoros Theodoulidis 2010 Iowa State University

On The Interaction Of An Eddy Current Coil With A Right-Angled Conductive Wedge, John R. Bowler, Theodoros Theodoulidis

John R. Bowler

A fundamental problem in eddy-current nondestructive evaluation is one of finding the quasi-static electromagnetic field of a cylindrical coil in the vicinity of the edge of a metal block. Although the field can be calculated numerically, an effective analytical approach can potentially provide a better understanding of the edge fields and form the basis of a procedure for solving a whole class of related edge problems including edge structures that contain corner cracks. One can represent the metal block as a conductive quarter space in an unbounded region. However, it has been found that the analysis is more straightforward if ...


Dynamic Modeling And Ascent Flight Control Of Ares-I Crew Launch Vehicle, Wei Du 2010 Iowa State University

Dynamic Modeling And Ascent Flight Control Of Ares-I Crew Launch Vehicle, Wei Du

Graduate Theses and Dissertations

This research focuses on dynamic modeling and ascent flight control of large flexible launch vehicles such as the Ares–I Crew Launch Vehicle (CLV). A complete set of six–degrees–of–freedom dynamic models of the Ares–I, incorporating its propulsion, aerodynamics, guidance and control, and structural flexibility, is developed. NASA's Ares–I reference model and the SAVANT Simulink–based program are utilized to develop a Matlab–based simulation and linearization tool for an independent validation of the performance and stability of the ascent flight control system of large flexible launch vehicles. A linearized state–space model as well ...


A Selective Sampling Method For Imbalanced Data Learning On Support Vector Machines, Jong Myong Choi 2010 Iowa State University

A Selective Sampling Method For Imbalanced Data Learning On Support Vector Machines, Jong Myong Choi

Graduate Theses and Dissertations

The class imbalance problem in classification has been recognized as a significant research problem in recent years and a number of methods have been introduced to improve classification results. Rebalancing class distributions (such as over-sampling or under-sampling of learning datasets) has been popular due to its ease of implementation and relatively good performance. For the Support Vector Machine (SVM) classification algorithm, research efforts have focused on reducing the size of learning sets because of the algorithm's sensitivity to the size of the dataset. In this dissertation, we propose a metaheuristic approach (Genetic Algorithm) for under-sampling of an imbalanced dataset ...


Rapid Optimization Of Interior Permanent Magnet (Ipm) Machines Using The Response Surface Method And Dimensionless Parameters, Ron D. Bremner 2010 Iowa State University

Rapid Optimization Of Interior Permanent Magnet (Ipm) Machines Using The Response Surface Method And Dimensionless Parameters, Ron D. Bremner

Graduate Theses and Dissertations

The primary objective for this work is to create a method to rapidly optimize interior permanent magnet (IPM) machines. For this research, a method was created called dimensionless optimization (DO). Eight dimensionless parameters determine nineteen dimensions of the machine based on design rules, stresses in the rotor and back EMF. Given a maximum torque specification and a local design space, a hypercube design of 64 machines is created using an 8 factor I-optimal design. Analysis is performed using a commercial program which incorporates electromagnetic FEA, and provides the current and phase angle requirements, and efficiency of the machines at the ...


A Microfluidic Method To Measure Diffusion In Hydrogels, Andrew Lee Litzenberger 2010 Bucknell University

A Microfluidic Method To Measure Diffusion In Hydrogels, Andrew Lee Litzenberger

Master’s Theses

A novel microfluidic method is proposed for studying diffusion of small molecules in a hydrogel. Microfluidic devices were prepared with semi-permeable microchannels defined by crosslinked poly(ethylene glycol) (PEG). Uptake of dye molecules from aqueous solutions flowing through the microchannels was observedoptically and diffusion of the dye into the hydrogel was quantified. To complement the diffusion measurements from the microfluidic studies, nuclear magnetic resonance(NMR) characterization of the diffusion of dye in the PEG hydrogels was performed. The diffusion of small molecules in a hydrogel is relevant to applications such asdrug delivery and modeling transport for tissue-engineering applications. The diffusion ...


Microfluidic Single Cell Sorting And Trapping Using Dual Spiral Channels, Pooja Ramesh 2010 Iowa State University

Microfluidic Single Cell Sorting And Trapping Using Dual Spiral Channels, Pooja Ramesh

Graduate Theses and Dissertations

The recent research and development of microfluidic systems for biological and chemical analysis has enabled interfacing and analyzing single or small population of biological cells. In this thesis, we describe a passive microfluidic device with dual spiral geometry for the separation and single cell trapping from a heterogeneous mixture. The device makes use of two spirals to sort and trap cells. Cells flowing in the primary channel experience centrifugal acceleration as they travel along the spiral. A combination of Dean drag force and inertial lift force acting on the cells in the primary channel, cause them to migrate towards the ...


Numerical Study On Mixture Formation Characteristics In A Direct-Injection Hydrogen Engine, Sujith Sukumaran 2010 Iowa State University

Numerical Study On Mixture Formation Characteristics In A Direct-Injection Hydrogen Engine, Sujith Sukumaran

Graduate Theses and Dissertations

Numerical modeling of direct hydrogen injection and in-cylinder mixture formation is performed in this paper. Numerical studies on direct-injection hydrogen engines are very limited due mainly to the complexity in modeling the physical phenomena associated with the high-velocity gas jet. The high injection pressure will result in a choked flow and develop an underexpanded jet at the nozzle exit, which consists of oblique and normal shock waves. A robust numerical model and a very fine computational mesh are required to model these phenomena. However, a very fine mesh may not be feasible in the practical engine application. Therefore, in this ...


A Novel And Cost-Effective Hydrogen Sulfide Removal Technology Using Tire Derived Rubber Particles, Andrea Mary Siefers 2010 Iowa State University

A Novel And Cost-Effective Hydrogen Sulfide Removal Technology Using Tire Derived Rubber Particles, Andrea Mary Siefers

Graduate Theses and Dissertations

Hydrogen sulfide (H2S) is corrosive, toxic, and produced during the anaerobic digestion process at wastewater treatment plants. Tire derived rubber particles (TDRPTM) and other rubber material (ORMTM) are recycled waste rubber products distributed by Envirotech Systems, Inc (Lawton, IA). They were found to be effective at removing H2S from biogas in a previous study. A scrubber system utilizing TDRPTM and ORMTM was tested at the Ames Water Pollution Control Facility (WPCF) to determine operational conditions that would optimize the amount of H2S removed from biogas in order to allow for ...


Survey Of Gas-Liquid Mass Transfer In Bioreactors, Enes Kadic 2010 Iowa State University

Survey Of Gas-Liquid Mass Transfer In Bioreactors, Enes Kadic

Graduate Theses and Dissertations

Bioreactors are becoming more important in the production of biobased products such as proteins, medicines, and renewable fuels. The economic viability of these processes is dependent on the bioreactor's ability to aid the microorganism and provide a friendly environment. One of the important microorganism requirements is proper gas concentrations so that the microorganism has the necessary inputs for proper metabolism. These gas concentrations are obtained and maintained through optimized gas-liquid mass transfer and mixing, also known as hydrodynamics. Other bioreactor responsibilities include damage mitigation and bioreactor volume utilization. A proper bioreactor design should also maximize profitability through ease of ...


Acid Catalyzed Carbohydrate Degradation And Dehydration, Basak Cinlar 2010 Iowa State University

Acid Catalyzed Carbohydrate Degradation And Dehydration, Basak Cinlar

Graduate Theses and Dissertations

Facile commercial production of versatile polyfunctional compounds from biomass constitutes a great challenge for establishing a sustainable chemical industry. One such example is the production of furfural and hydroxymethyl furfural via dehydration of pentoses and hexoses. Identified as primary building blocks in polymer industry, their massive production is highly desired, yet suffers from several problems, such as feedstock availability, low product yields due to excessive side reactions and lack of an industrially feasible heterogeneous catalyst.

Organic acid functional groups incorporated onto mesoporous silica offer well defined catalytic sites beside their unique textural properties and therefore could be considered as promising ...


Control And Diagnosis Of Real-Time Systems Under Finite-Precision Measurement Of Time, Songyan Xu 2010 Iowa State University

Control And Diagnosis Of Real-Time Systems Under Finite-Precision Measurement Of Time, Songyan Xu

Graduate Theses and Dissertations

A discrete event system (DES) is an event-driven system that evolves according to abrupt occurrences of discrete changes (events). The domain of such systems encompasses aspects of many man-made systems such as manufacturing systems, telephone networks, communication protocols, traffic systems, embedded software, asynchronous hardware, robotics, etc.

Supervisory control theory for DESs studies the existence and synthesis of the supervisory controllers, namely, supervisors that restrict the system behaviors by dynamically disabling certain controllable events so that the controlled close-loop system could behave as desired. Extensive work on supervisory control of untimed DESs exists and the extension to the timed setting has ...


Differentiating Ethernet Devices Using Normal Link Pulse With Efficient Computation And The Impacts On Performance, Wade David Paustian 2010 Iowa State University

Differentiating Ethernet Devices Using Normal Link Pulse With Efficient Computation And The Impacts On Performance, Wade David Paustian

Graduate Theses and Dissertations

The tolerances in manufacturing Ethernet devices cause detectable differences in the signals sent by two different devices. Here, the design space is examined for using the IEEE 802.3 Normal Link Pulse (NLP) as the signal to use for differentiating devices. A previously collected set of NLP records as well as new sets of NLP data are used for testing the detection algorithm. Further tests have been run to determine the possibility of reducing the sampling rate to the point where Analogue-to-Digital Converters (ADCs) are more readily available and inexpensive. Reduced precision at each decimation was also tested. The design ...


Effect Of Temperature Variation On The Magnetostrictive Properties Of Coalxfe2−Xo4, Ikenna C. Nlebedim, N. Ranvah, Y. Melikhov, P. I. Williams, J. E. Snyder, A. J. Moses, David C. Jiles 2010 Cardiff University

Effect Of Temperature Variation On The Magnetostrictive Properties Of Coalxfe2−Xo4, Ikenna C. Nlebedim, N. Ranvah, Y. Melikhov, P. I. Williams, J. E. Snyder, A. J. Moses, David C. Jiles

David C. Jiles

The effect of temperature variation on the magnetoelasticproperties of the CoAlxFe2−xO4 system (for x=0.0, 0.2, 05, and 0.7) has been studied. Substitution of Al3+ for Fe3+ was found to lower the Curie temperature of the samples and to change the lattice parameter. The magnitude of peak to peak magnetostriction, strain sensitivity, magnetomechanical hysteresis, and relative contributions of λ111 and λ100 to the resultant magnetostriction were found to vary with temperature. The results show the possibility of tailoring the magnetoelasticproperties of highly magnetostrictive cobalt ferrite at temperatures of interest by cation substitution.


Cast Data Matrix Symbols Performance Characterization, Greg Carl Saveraid 2010 Iowa State University

Cast Data Matrix Symbols Performance Characterization, Greg Carl Saveraid

Graduate Theses and Dissertations

Data matrix symbols are used as a robust means of unique part identification in many industries. Research of cast data matrix symbols has been limited and expected symbol performance unknown. To develop knowledge of cast data matrix symbol performance, the investigation initially focused on feasibility of casting data matrix symbol. Results of a feasibility experiment led to further investigation of cast symbol design expected performance.

Bump marks were evaluated initially due to the inherent ease of production and use in previous cast data matrix applications. The results indicate Bump mark geometry is problematic, due to the inherent nature of shadow ...


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