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2015

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Articles 11611 - 11640 of 12617

Full-Text Articles in Physical Sciences and Mathematics

An Exposition Of Kasteleyn's Solution Of The Dimer Model, Eric Stucky Jan 2015

An Exposition Of Kasteleyn's Solution Of The Dimer Model, Eric Stucky

HMC Senior Theses

In 1961, P. W. Kasteleyn provided a baffling-looking solution to an apparently simple tiling problem: how many ways are there to tile a rectangular region with dominos? We examine his proof, simplifying and clarifying it into this nearly self-contained work.


Chromatic Polynomials And Orbital Chromatic Polynomials And Their Roots, Jazmin Ortiz Jan 2015

Chromatic Polynomials And Orbital Chromatic Polynomials And Their Roots, Jazmin Ortiz

HMC Senior Theses

The chromatic polynomial of a graph, is a polynomial that when evaluated at a positive integer k, is the number of proper k colorings of the graph. We can then find the orbital chromatic polynomial of a graph and a group of automorphisms of the graph, which is a polynomial whose value at a positive integer k is the number of orbits of k-colorings of a graph when acted upon by the group. By considering the roots of the orbital chromatic and chromatic polynomials, the similarities and differences of these polynomials is studied. Specifically we work toward proving a conjecture …


A Combinatorial Exploration Of Elliptic Curves, Matthew Lam Jan 2015

A Combinatorial Exploration Of Elliptic Curves, Matthew Lam

HMC Senior Theses

At the intersection of algebraic geometry, number theory, and combinatorics, an interesting problem is counting points on an algebraic curve over a finite field. When specialized to the case of elliptic curves, this question leads to a surprising connection with a particular family of graphs. In this document, we present some of the underlying theory and then summarize recent results concerning the aforementioned relationship between elliptic curves and graphs. A few results are additionally further elucidated by theory that was omitted in their original presentation.


Microtopographic Ecohydrology Of A Forested Wetland In Louisiana, Yu-Hsin Hsueh Jan 2015

Microtopographic Ecohydrology Of A Forested Wetland In Louisiana, Yu-Hsin Hsueh

LSU Master's Theses

Coastal wetland forest ecosystems rely on the intimate interactions of hydrology, salinity, and coastal forest vegetation. The boundary between marsh and forest is often where hummock-swale terrain exists. It remains unknown as to the degree to which trees may experience varied salinity level within hummocks provided with freshwater flux. This study examined the hydrological regime of the hummock-swale terrain that resulted in salinity variation and whether freshwater source exists for baldcypress. Natural tracers of stable isotopes of water and salinity were applied to understand the sources of water. To better examine the tracers used, we conducted several experiments to gain …


Rare Earth Element Patterns In Conodont Apatite From The Upper Ordovician: Testing Enrichment Sources And Possible Oceanographic Changes, Cody Christian Schulte Jan 2015

Rare Earth Element Patterns In Conodont Apatite From The Upper Ordovician: Testing Enrichment Sources And Possible Oceanographic Changes, Cody Christian Schulte

LSU Master's Theses

The Mohawkian series of the Middle Late Ordovician was a time of great lithological and faunal changes that coincide with a positive ä13C excursion known as the Guttenberg Isotopic Carbon Excursion (GICE). Two prevailing hypotheses have been proposed to explain the cause of these changes. The “cold-water” hypothesis suggests that global cooling caused the tropical belt to shrink and cold water to invade the epicontinental sea while the “tectonic-forcing” hypothesis suggests that increased weathering rates led to basinal deepening, resulting in cooler oceanic waters invading the midcontinent sea. This study tests if regional tectonics caused by the Taconic Orogeny led …


Anthropogenic Impacts On Soil Microbial Processes In Coastal Wetlands: Nutrient Loading And Rising Co2 Levels, Havalend Ellen Steinmuller Jan 2015

Anthropogenic Impacts On Soil Microbial Processes In Coastal Wetlands: Nutrient Loading And Rising Co2 Levels, Havalend Ellen Steinmuller

LSU Master's Theses

Atmospheric carbon dioxide (CO2) levels and global eutrophication are anthropogenic stressors impacting the environment of specific interest in wetland systems. Wetlands occupy a critical interface between terrestrial and aquatic environments. Fertilizer use for agriculture and treated wastewater disposal has increased nutrient loading to wetlands. Conflicting results on impacts of nitrogen loading to coastal wetland soils have been reported, though most studies have investigated short-term impacts of nutrient loading, not long-term integrated impacts. I investigated an 11-year period of nutrient loading on soils in an oligohaline coastal wetland. Nitrogen treatments of 0, 50, 200, and 1200 kg ha-1 yr-1 were paired …


Synoptic Patterns Associated With Northeast And South East Ice Storms, Ricardo Vargas Jan 2015

Synoptic Patterns Associated With Northeast And South East Ice Storms, Ricardo Vargas

Dissertations and Theses

Wintertime storms that produce precipitation events such as snow, freezing rain, and ice pellets cause significant damage to utility services and disrupt travel. These synoptic systems involve deep isothermal regions where warm, moist air over-runs surface sub-freezing air. Much attention has been focused on Northeast ice storms, where a study by Cortinas et al. (2004) identified the Northeast as the region with the highest spatial distribution of freezing rain and ice pellets. Castellano (2012) also identified 2 types events where ice storms occur in the Northeast as a result of cold-air intrusions from Canada and from an absence of cold …


Degradation Of Carbon Tetrachloride Using Hydrophobic Green Rust, Sheena Bowman Jan 2015

Degradation Of Carbon Tetrachloride Using Hydrophobic Green Rust, Sheena Bowman

Dissertations and Theses

Hydrophobic green rusts (GR) were produced using aerial oxidation of solutions containing bis (2-ethylhexyl) sulfosuccinate (BIS) and sodium N-lauroylsarcosinate (SNLS), iron (II) sulfate and sodium hydroxide. The synthesis was conduced at constant pH 8.0±0.1 for the duration of 1-3 hrs. Partition tests showed GRBIS and GRSNLS suspended in the organic phase (tetrachloroethylene). Through X-ray diffraction analysis both GRs exhibit similar patterns to Green Rust II, an inorganic form of GR. The kinetics of GR reductive dechlorination of carbon tetrachloride (CT) was investigated. CT at high concentrations was degraded at high percentages for GRBIS-3, 88.5% and GRSNLS-5, 97.6%. Their reactions were …


Metadata And Linked Data In Word Sense Disambiguation, Matthew Corsmeier Jan 2015

Metadata And Linked Data In Word Sense Disambiguation, Matthew Corsmeier

Library Philosophy and Practice (e-journal)

Word Sense Disambiguation (WSD) can be assisted by taking advantage of the metadata embedded in the various ontologies, lexica, databases, etc… that exist in the Semantic Web. Automated processes that exploit the links already present in the Semantic Web can strengthen parsing of word senses by using user-contributed and semantically-linked data. These processes are only possible because of a commitment to interoperability and the creation of shared standards. This paper will review some of the most heavily used Linguistic Linked Open Data (LLOD) tools and models which show the most promise for using metadata to alleviate problems caused by polysemous …


Extracting Flow Features Using Bag-Of-Features And Supervised Learning Techniques, Yifei Li Jan 2015

Extracting Flow Features Using Bag-Of-Features And Supervised Learning Techniques, Yifei Li

Dissertations, Master's Theses and Master's Reports

Measuring the similarity between two streamlines is fundamental to many important flow data analysis and visualization tasks such as feature detection, pattern querying and streamline clustering. This dissertation presents a novel streamline similarity measure inspired by the bag-of-features concept from computer vision. Different from other streamline similarity measures, the proposed one considers both the distribution of and the distances among features along a streamline. The proposed measure is tested in two common tasks in vector field exploration: streamline similarity query and streamline clustering. Compared with a recent streamline similarity measure, the proposed measure allows users to see the interesting features …


Deterministic And Stochastic Inversion Techniques Used To Predict Porosity: A Case Study From F3-Block, Hao Wu Jan 2015

Deterministic And Stochastic Inversion Techniques Used To Predict Porosity: A Case Study From F3-Block, Hao Wu

Dissertations, Master's Theses and Master's Reports

Within large-scale sigmoidal bedding of the F3-block in the shallow zone there appear to be some indicators of hydrocarbon deposits. In order to characterize target zone in the sigmoidal bedding, I combine the analysis of inverted results of post-stack seismic data with rock-physics relationships developed from well log data to predict the porosity, which ranges from 20% to 33%, for different system tracts in this area. The methods used in this study include conventional deterministic inversion and novel stochastic inversion. Through a rock physics analysis of the density, velocity and gamma-ray logs in two wells, I constructed relationships between the …


Legacy And Opportunity In Northern Hardwood Forests, Wilfred Previant Jan 2015

Legacy And Opportunity In Northern Hardwood Forests, Wilfred Previant

Dissertations, Master's Theses and Master's Reports

Northern hardwood management reflects a combination of historic exploitation, current efforts for sustainability, and a desired future condition that incorporates complexity, resiliency, and adaptability. Stand structure and species diversity were assessed at two study locations within Michigan (USA): (1) long-term northern hardwood cutting trials at the Ford Forestry Center (FFC; Michigan Technological University, USA); and (2) vernal pool habitat within Pictured Rocks National Lakeshore (PRNL). Following the fifth cutting entry at the FFC, age structure and pre- and post-harvest relative species abundance, stocking, and volume were compared across three diameter-limit treatments, three residual basal area treatments, and an uncut control. …


Laboratory And Field Investigation Of Mixing, Morphology And Optical Properties Of Soot And Secondary Organic Aerosols, Noopur Sharma Jan 2015

Laboratory And Field Investigation Of Mixing, Morphology And Optical Properties Of Soot And Secondary Organic Aerosols, Noopur Sharma

Dissertations, Master's Theses and Master's Reports

Soot/ black carbon particles are believed to be the second largest anthropogenic contributor to the Earth’s radiative forcing, and are emitted from combustion processes. Freshly emitted soot has a fractal-like structure in which monomers are arranged into branched chain-like configuration. In the atmosphere, soot mixes with and is processed by interacting with other co-existing particle and vapors. The processing that soot undergo after emission alters its morphology; for example, condensation of vapors results into coated, mixed or compacted soot depending upon the environmental conditions. Changes in soot morphology have a strong and direct influence on its optical properties.

The unique …


Investigating Diurnal And Seasonal Climatic Response To Land Use And Land Cover Change Over Monsoon Asia With The Community Earth System Model, Rezaul Mahmood Jan 2015

Investigating Diurnal And Seasonal Climatic Response To Land Use And Land Cover Change Over Monsoon Asia With The Community Earth System Model, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.


Neural Network Analysis On The Effect Of Heat Fluxes On Greenhouse Gas Emissions From Anaerobic Swine Waste Treatment Lagoon, N. Lovanh, J. Loughrin, M. Rysz, A. I. Quintanar, B. T. Oh, Rezaul Mahmood Jan 2015

Neural Network Analysis On The Effect Of Heat Fluxes On Greenhouse Gas Emissions From Anaerobic Swine Waste Treatment Lagoon, N. Lovanh, J. Loughrin, M. Rysz, A. I. Quintanar, B. T. Oh, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.


Experimental Demonstration Of Localized Excess Protons At A Water-Membrane Interface, Haitham A. Saeed, James W. Lee Jan 2015

Experimental Demonstration Of Localized Excess Protons At A Water-Membrane Interface, Haitham A. Saeed, James W. Lee

Chemistry & Biochemistry Faculty Publications

The widespread Mitchellian proton motive force equation has recently been revised with the proton-electrostatics localization hypothesis, which, for the first time, successfully elucidates the 30-year longstanding energetic conundrum of ATP synthesis in alkalophilic bacteria. To demonstrate the fundamental behavior of localized protons in a pure water-membrane-water system in relation to the newly derived pmf equation, excess protons and excess hydroxyl anions were generated by utilizing an "open-circuit" water-electrolysis system and their distributions were tested using a proton-sensing aluminum membrane. The proton-sensing film placed at the membrane-water interface displayed dramatic localized proton activity while that placed into the bulk water phase …


Interesting Properties Of P-, D-, And F-Block Elements When Coordinated With Dipicolinic Acid And Its Derivatives As Ligands: Their Use As Inorganic Pharmaceuticals, Michael J. Celestine, Jimmie L. Bullock, Shivani Boodram, Varma H. Rambaran, Alvin A. Holder Jan 2015

Interesting Properties Of P-, D-, And F-Block Elements When Coordinated With Dipicolinic Acid And Its Derivatives As Ligands: Their Use As Inorganic Pharmaceuticals, Michael J. Celestine, Jimmie L. Bullock, Shivani Boodram, Varma H. Rambaran, Alvin A. Holder

Chemistry & Biochemistry Faculty Publications

This is a review of the literature concerning the interesting properties of p-, d-, and f-block elements when coordinated with 2,6-pyridinedicarboxylic acid (dipicolinic acid, H2dipic) and its derivatives as ligands, with a focus on their use as inorganic pharmaceuticals. Some of the complexes reported were used as insulin-like, bioimaging contrasting agents, antimicrobial agents, and anticancer agents.


Dye-Sensitized Solar Cells Based On Dyes Extracted From Dried Plant Leaves, Sofyan A. Taya, Taher M. El-Agez, Kamal S. Elrefi, Monzir S. Abdel-Latif Jan 2015

Dye-Sensitized Solar Cells Based On Dyes Extracted From Dried Plant Leaves, Sofyan A. Taya, Taher M. El-Agez, Kamal S. Elrefi, Monzir S. Abdel-Latif

Turkish Journal of Physics

In this work, natural dyes were extracted from dried plant leaves of plant cream, apricot, figs, apples, sage, thyme, mint, Ziziphus jujuba, orange, shade tree, basil, berry, Mirabelle plum, Victoria plum, peach, mango, pomegranate, banana, guava, and fluoridation-treated plant. The extracts were used as photosensitizers for dye-sensitized solar cells (DSSCs). The cells were assembled using nanostructured TiO_2 films. The best performance was observed for the DSSC sensitized with Ziziphus jujuba with an efficiency of 1.077%. The impedance spectroscopy of 3 cells was carried out and the equivalent circuits were found.


Studies On Mass Attenuation Coefficient, Mass Energy Absorption Coefficient, And Kerma For Fe Alloys At Photon Energies Of 17.44 To 51.70 Kev, Demet Yilmaz, Yusuf Şahi̇n, Lütfü Demi̇r Jan 2015

Studies On Mass Attenuation Coefficient, Mass Energy Absorption Coefficient, And Kerma For Fe Alloys At Photon Energies Of 17.44 To 51.70 Kev, Demet Yilmaz, Yusuf Şahi̇n, Lütfü Demi̇r

Turkish Journal of Physics

The mass attenuation coefficient (mu_m), the mass energy absorption coefficient (mu_{en}/ rho), and kerma relative to air were determined for some alloys, namely Fe_{0.5}Cr_{0.5}, Fe_{0.7}Cr_{0.3}, Fe_{0.8}Cr_{0.2}, Fe_{0.9}Cr_{0.1}, Fe_{0.2}Ni_{0.8}, Fe_{0.3}Ni_{0.7}, Fe_{0.5}Ni_{0.5}, Fe_{0.6}Ni_{0.4}, Fe_{0.7}Ni_{0.3}, and Fe_{0.8}Ni_{0.2}, at 17.44, 19.63, 22.10, 24.90, 32.06, 36.39, 37.26, 43.74, 44.48, 50.38, and 51.70 photon energies by using an HPGe detector with a resolution of 182 eV at 5.9 keV. The experimental results of mu_m were compared with the theoretical results. The theoretical values of mu_{en}/ rho were compared with the semiempirical values. It was observed that kerma values relative to air values were different in Fe-Ce …


A Computational Study On The Interaction Between O$_{2}$ And Pristine And Ge-Doped Aluminum Phosphide Nanotubes, Mahdi Rezaei Sameti, Alireza Kazemi Jan 2015

A Computational Study On The Interaction Between O$_{2}$ And Pristine And Ge-Doped Aluminum Phosphide Nanotubes, Mahdi Rezaei Sameti, Alireza Kazemi

Turkish Journal of Physics

In this research the interaction between oxygen molecules and the outside and inside surfaces of pristine and Ge-doped (4,4) armchair and (6,0) zigzag models of aluminum phosphide nanotubes (AlPNTs) was systematically investigated using density function theory. Structural parameters, adsorption energy, quantum parameters, HOMO/LUMO orbitals, and nuclear quadrupole resonance (NQR) parameters were calculated for all models of AlPNTs. The aim of this work was to investigate the effects of Ge doping and O$_{2}$ adsorption on the electrical and structural parameters of (4,4) armchair and (8,0) zigzag models of AlPNTs. The results revealed that adsorption energies for all models were negative with …


Description Of The Yrast Superdeformed Bands In Even-Even Nuclei In A $\Sim$ 190 Region Using The Nuclear Softness Model, Ali Khalaf, Karima Abdelmageed, Manal Sirag Jan 2015

Description Of The Yrast Superdeformed Bands In Even-Even Nuclei In A $\Sim$ 190 Region Using The Nuclear Softness Model, Ali Khalaf, Karima Abdelmageed, Manal Sirag

Turkish Journal of Physics

A two-parameter nuclear softness (NS2) model for the transition energies is proposed by treating the variation of the moment of inertia with spin. The model has been applied to the yrast superdeformed (SD) bands in even-even nuclei in the mass region A $\sim $ 190. The model parameters have been determined from the fitting procedure in order to minimize the relative root mean square deviation between the experimental E2 transition $\gamma $-ray energies and the calculated ones. The basic experimental data on SD bands are given in the form of a series of $\gamma $-ray transitional energies and the spins …


A Full Relativistic Treatment In Analyzing $\Alpha $-$^{12}$C And $\Alpha $-$^{40,42,44,48}$Ca Elastic Scattering Data At 1.37 Gev, Zuhair Fayyad Mahmoud Shehadeh Jan 2015

A Full Relativistic Treatment In Analyzing $\Alpha $-$^{12}$C And $\Alpha $-$^{40,42,44,48}$Ca Elastic Scattering Data At 1.37 Gev, Zuhair Fayyad Mahmoud Shehadeh

Turkish Journal of Physics

A simple optical potential of Woods-Saxon form is used within the framework of the Klein-Gordon equation, for the first time, to analyze the elastic differential cross sections for 1.37 GeV (lab) incident $\alpha $-particles on $^{12}$C and calcium isotopes $^{40,42,44,48}$Ca. The relativistic energy-momentum relation assures the need for relativistic calculations. As such, the previously determined parameters of all optical potential forms, used in the nonrelativistic Schrödinger equation and successfully analyzing the $\alpha $-$^{12}$C and $\alpha $-$^{40,42,44,48}$Ca data at 1.37 GeV, are to be revised. In the presence of Coulomb potential, as in the cases under consideration, the asymptotic solution of …


Identifying A Mechanism For An Infiltration Threshold From The Sunflower River, Ms To The Underlying Alluvial Aquifer, Austin Cole Patton Jan 2015

Identifying A Mechanism For An Infiltration Threshold From The Sunflower River, Ms To The Underlying Alluvial Aquifer, Austin Cole Patton

Electronic Theses and Dissertations

Long-term groundwater level and stream stage measurements at a USGS coupled groundwater stream-gaging station located on the Sunflower River in Sunflower, MS show an apparent stage-threshold for infiltration to the underlying alluvial aquifer. This site is located near the center of a large regional groundwater cone of depression in the Mississippi River Valley alluvial aquifer. The USGS well (termed well 3 in this study) was thought to be completed in the regional shallow aquifer, though often recording anomalously high water levels relative to other wells in the region. The purpose of this research was to identify the responsible mechanism for …


Fscan Code Development For Advanced Ligo Detector Characterization, Cody Arceneaux Jan 2015

Fscan Code Development For Advanced Ligo Detector Characterization, Cody Arceneaux

Electronic Theses and Dissertations

The Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) is an experiment designed to provide direct detection of gravitational waves. Its searches for periodic gravitational waves are highly susceptible to long-duration noise that appears as spectral lines. FScan is a tool for finding spectral lines and is used to identify the lines that appear in the gravitational-wave data; it is also used to characterize LIGO's detectors. This thesis details work in rewriting the plotting portion of FScan, making improvements to the FScan driver script, and writing code to assist in the tracking of wandering spectral lines. In particular, this thesis presents the …


Specification And Mechanical Verification Of Performance Profiles Of Software Components, Nighat Yasmin Jan 2015

Specification And Mechanical Verification Of Performance Profiles Of Software Components, Nighat Yasmin

Electronic Theses and Dissertations

Software performance predictability is vital to a system design and unpredictable performance is a leading cause of software failure. The emphasis of this dissertation is on verification that component-based software performs as specified. Performance profiles (specifications) depend on functional specifications and are necessary for all components for modular verification. Modular verification process is scalable because it uses profiles as contracts and allows verification of a single component in isolation with the assumption that any underlying component would have already been verified or will be verified to meet its specifications independently. This dissertation presents an integration of performance specification (profiles) with …


Secondary Metabolites From Sambucus Ebulus, İrem Atay, Hasan Kirmizibekmez, Ahmet Ceyhan Gören, Erdem Yeşi̇lada Jan 2015

Secondary Metabolites From Sambucus Ebulus, İrem Atay, Hasan Kirmizibekmez, Ahmet Ceyhan Gören, Erdem Yeşi̇lada

Turkish Journal of Chemistry

A new nonglycosidic iridoid, sambulin B (1), was isolated from the methanol extract of Sambucus ebulus L. leaves along with a recently reported new nonglycosidic iridoid, 10-O-acetylpatrinoside aglycone (sambulin A) (2); 2 flavonoids, isorhamnetin-3-O-\beta-D-glucopyranoside (3) and isorhamnetin-3-O-rutinoside (4); and a mixture of 2 flavonoids (5), quercetin-3-O-\beta-D-glucopyranoside and quercetin-3-O-\beta-D-galactopyranoside. Their structures were elucidated by 1-D and 2-D nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS) experiments.


Amperometric Biosensing Of Ethanol Based On Integration Of Alcohol Dehydrogenase With A Pt/Ppy--Pvs/Mb Electrode, Özlem Çolak, Fatma Arslan Jan 2015

Amperometric Biosensing Of Ethanol Based On Integration Of Alcohol Dehydrogenase With A Pt/Ppy--Pvs/Mb Electrode, Özlem Çolak, Fatma Arslan

Turkish Journal of Chemistry

A novel amperometric ethanol biosensor with alcohol dehydrogenase (ADH) and nicotinamide adenine dinucleotide (NAD^+) on polypyrrole--polyvinylsulfonate (PPy-PVS) film was accomplished. Meldola's blue (MB) was used as a mediator; it can facilitate the electron transfer that involves a chemical interaction between the electrode surface and NADH. Determination of ethanol was carried out by the oxidation of MB at --0.072 V vs. Ag/AgCl. The effects of pH and temperature were investigated and optimum parameters were found to be 7.0 and 40 °C, respectively. There are 2 linear parts at 1.0 \mu M--10.0 \mu M (R^2 = 0.993) and 0.01 mM--0.1 mM (R^2 …


Purification And Characterization Of Nadph-Cytochrome P450 Reductase From Lake Van Fish Liver Microsomes And Investigation Of Some Chemical And Metals' Effects On The Enzyme Activity, Müslüm Kuzu, Mehmet Çi̇ftci̇ Jan 2015

Purification And Characterization Of Nadph-Cytochrome P450 Reductase From Lake Van Fish Liver Microsomes And Investigation Of Some Chemical And Metals' Effects On The Enzyme Activity, Müslüm Kuzu, Mehmet Çi̇ftci̇

Turkish Journal of Chemistry

NADPH-cytochrome P450 reductase was purified from Lake Van fish liver microsomes by primary and secondary DEAE-cellulose column chromatograph with 20.46 \mu M/min/mg enzyme specific activities, 54.4% purification yield, and purification of 38-fold. The purity of the enzyme was established, and its monomer molecular weight was determined by SDS-polyacrylamide gel electrophoresis. SDS-PAGE results showed a single band and the molecular weight of NADPH-cytochrome P450 reductase was 70 kDa. In addition, optimum ionic strength, optimum pH, optimum temperature, and stable pH values were determined for the enzyme in the kinetic studies performed. K_M and V_{max} were determined for NADPH and cytochrome c. …


Low-Cost Sliding Mode Control Of Wecs Based On Dfig With Stability Analysis, Abdelhak Djoudi, Hachemi Chekireb, El Madjid Berkouk, Seddik Bacha Jan 2015

Low-Cost Sliding Mode Control Of Wecs Based On Dfig With Stability Analysis, Abdelhak Djoudi, Hachemi Chekireb, El Madjid Berkouk, Seddik Bacha

Turkish Journal of Electrical Engineering and Computer Sciences

The aim of this work is to developing sliding mode control of active and reactive stator powers produced by a wind energy conversion system (WECS), based on doubly fed induction generator (DFIG). A flux estimation model and rotor current sensor are no longer required. The controller is developed from the DFIG nonlinear-coupled model. Moreover, the global stability and the DFIG states' boundedness when our low-cost sliding mode control is applied are established analytically. It is revealed that the $(dq)$ components of the rotor flux remain near their nominal values. Our approach is validated via simulation in the case of a …


Synthesis Of Methyl 4-(9h-Carbazole-9-Carbanothioylthio) Benzoate: Electropolymerization And Impedimetric Study, Murat Ateş, Nesi̇mi̇ Uludağ, Fati̇h Arican, Tolga Karazehi̇r Jan 2015

Synthesis Of Methyl 4-(9h-Carbazole-9-Carbanothioylthio) Benzoate: Electropolymerization And Impedimetric Study, Murat Ateş, Nesi̇mi̇ Uludağ, Fati̇h Arican, Tolga Karazehi̇r

Turkish Journal of Chemistry

Methyl 4-((9H-(carbazole-9-carbanothioylthio) benzoate (MCzCTB) was chemically synthesized and characterized by FTIR, ^1H NMR, and ^{13}C NMR. A novel synthesized monomer was electropolymerized on a glassy carbon electrode (GCE) in various initial molar concentrations of [MCzCTB]_0= 1, 3, 5, and 10 mM in 0.1 M NaClO_4/CH_3CN and 1 M H_2SO_4. P(MCzCTB)/GCE was characterized by cyclic voltammetry, Fourier transform infrared-attenuated transmittance reflectance, scanning electron microscopy-energy dispersive X-ray, and electrochemical impedance spectroscopy. The capacitive behavior of the modified electrode was obtained by Nyquist, Bode-magnitude, and Bode-phase plots. The highest capacitance at low frequency was obtained as \sim 53.1 mF cm^{-2} from Nyquist plot …