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Full-Text Articles in Engineering

Programmable Cmos Analog-To-Digital Converter Design And Testability, Rajiv Soundararajan Jan 2012

Programmable Cmos Analog-To-Digital Converter Design And Testability, Rajiv Soundararajan

LSU Doctoral Dissertations

In this work, a programmable second order oversampling CMOS delta-sigma analog-to-digital converter (ADC) design in 0.5µm n-well CMOS processes is presented for integration in sensor nodes for wireless sensor networks. The digital cascaded integrator comb (CIC) decimation filter is designed to operate at three different oversampling ratios of 16, 32 and 64 to give three different resolutions of 9, 12 and 14 bits, respectively which impact the power consumption of the sensor nodes. Since the major part of power consumed in the CIC decimator is by the integrators, an alternate design is introduced by inserting coder circuits and reusing the …


Plasmonic Devices For Manipulating Light At The Nanoscale: Slow-Light Waveguides And Compact Couplers, Yin Huang Jan 2012

Plasmonic Devices For Manipulating Light At The Nanoscale: Slow-Light Waveguides And Compact Couplers, Yin Huang

LSU Doctoral Dissertations

In this dissertation, I explore new plasmonic structures and devices for manipulating light at the nanoscale: slow-light waveguides and compact couplers. I first introduce a plasmonic waveguide system, based on a plasmonic analogue of electromagnetically induced transparency (EIT), which supports a subwavelength slow-light mode, and exhibits a small group velocity dispersion. The system consists of a periodic array of two metal-dielectric-metal (MDM) stub resonators side-coupled to a MDM waveguide. Decreasing the frequency spacing between the two resonances increases the slowdown factor and decreases the bandwidth of the slow-light band. I also show that there is a trade-off between the slowdown …


New Coding/Decoding Techniques For Wireless Communication Systems, Yonas Gebregziabher Debessu Jan 2012

New Coding/Decoding Techniques For Wireless Communication Systems, Yonas Gebregziabher Debessu

LSU Doctoral Dissertations

Wireless communication encompasses cellular telephony systems (mobile communication), wireless sensor networks, satellite communication systems and many other applications. Studies relevant to wireless communication deal with maintaining reliable and efficient exchange of information between the transmitter and receiver over a wireless channel. The most practical approach to facilitate reliable communication is using channel coding. In this dissertation we propose novel coding and decoding approaches for practical wireless systems. These approaches include variable-rate convolutional encoder, modified turbo decoder for local content in Single-Frequency Networks, and blind encoder parameter estimation for turbo codes. On the other hand, energy efficiency is major performance issue …


Study On Permanent Magnet Transverse Flux Machine, Oleksandr Dobzhanskyi Jan 2012

Study On Permanent Magnet Transverse Flux Machine, Oleksandr Dobzhanskyi

LSU Doctoral Dissertations

This dissertation is concentrated mainly on the newest PMTF machine topology proposed and patented by Jacek F. Gieras in March 4, 2010. Such a topology (topology of 2010) is an object of this dissertation. A prototype that was built with 3D Finite Element Method (FEM) modeling of PMTF generator proves that the generator that was built on the basis of topology of 2010 has several significant disadvantages among which the greatest impact have high leakage flux losses. Applying FEM modeling, various steps to improve machine performance have been undertaken. Results obtained from modeling show, that keeping the same diameter and …


Controller Reduction For Linear Systems, Lili Kong Jan 2012

Controller Reduction For Linear Systems, Lili Kong

LSU Doctoral Dissertations

This dissertation proposes some H-infinity and H2 performance preserving controller reduction methods for linear systems. The proposed methods can guarantee robust stability and performance for the closed-loop system with the reduced order controllers. Several H-infinity stability and performance preserving controller reduction methods are proposed in this dissertation. It is shown that the weighting functions used in the proposed controller reduction methods can be directly obtained from the parametrization of the H-infinity controllers. Hence, comparing with the most existing controller reduction approaches, the proposed controller reduction methods require less computation and are easy to apply. At the same time, several algorithms …


Microfabrication Of Conductive Polymer Nanocomposite For Sensor Applications, Chaoxuan Liu Jan 2012

Microfabrication Of Conductive Polymer Nanocomposite For Sensor Applications, Chaoxuan Liu

LSU Doctoral Dissertations

This dissertation developed novel microfabrication techniques of conductive polymer nanocomposite and utilized this material as a functional element for various physical sensor applications. Microstructures of nanocomposite were realized through novel microcontact printing and laser ablation assisted micropatterning processes. Prototype devices including large-strain strain sensor and highly-sensitive pressure sensor were demonstrated showing distinct advantages over existing technologies. The polymer nanocomposite used in this work comprised elastomer poly(dimexylsiloxane) (PDMS) as polymer matrix and multi-walled carbon nananotubes (MWCNTs) as a conductive nanofiller. To achieve uniform distribution of carbon nanotubes within the polymer, an optimized dispersion process was developed, featuring a strong organic solvent—chloroform, …


Low Temperature Carbon Material Deposition With Photo-Enhanced Chemical Vapor Deposition, Kyungnam Kang Jan 2012

Low Temperature Carbon Material Deposition With Photo-Enhanced Chemical Vapor Deposition, Kyungnam Kang

LSU Doctoral Dissertations

Photo-enhanced chemical vapor deposition (CVD) technique is investigated here for low temperature deposition of carbon nanotubes (CNTs) and hexagonal diamond. Most current deposition methods require high substrate temperature. Photo-enhanced CVD utilizes light energy to dissociate carbon containing precursor molecules and hence has a potential for low temperature deposition. CCl4, having a high absorption coefficient compared to other commonly employed hydrocarbons in the UV emission spectrum from a Xe arc lamp, is selected as a carbon precursor in this work. Extensive experimentation conducted by varying Al/Ni/Al catalyst layer thicknesses on SiO2 coated Si substrates, substrate annealing temperature in the range 350 …