Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2014

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 10831 - 10860 of 12299

Full-Text Articles in Physical Sciences and Mathematics

Norden Structures Of Hessian Type, Arif Salimov, Aydin Gezer Jan 2014

Norden Structures Of Hessian Type, Arif Salimov, Aydin Gezer

Turkish Journal of Mathematics

In this paper, we show that Kähler (para-Kähler) manifolds admit a Norden--Hessian metric h = \nabla^2f if the function f is holomorphic (para-holomorphic), and we further consider the existence condition of para-Kähler structures for Norden--Hessian metrics.

Go to article

Equivariant Structure Constants For Hamiltonian-T-Spaces, Ho Hon Leung Jan 2014

Equivariant Structure Constants For Hamiltonian-T-Spaces, Ho Hon Leung

Turkish Journal of Mathematics

If there exists a set of canonical classes on a compact Hamiltonian-T-space in the sense of R Goldin and S Tolman, we derive some formulas for certain equivariant structure constants in terms of other equivariant structure constants and the values of canonical classes restricted to some fixed points. These formulas can be regarded as a generalization of Tymoczko's results.

Go to article

Moment Equalities For Sums Of Random Variables Via Integer Partitions And Faà Di Bruno's Formula, Dietmar Ferger Jan 2014

Moment Equalities For Sums Of Random Variables Via Integer Partitions And Faà Di Bruno's Formula, Dietmar Ferger

Turkish Journal of Mathematics

We give moment equalities for sums of independent and identically distributed random variables including, in particular, centered and specifically symmetric summands. Two different types of proofs, combinatorial and analytical, lead to 2 different types of formulas. Furthermore, the combinatorial method allows us to find the optimal lower and upper constants in the Marcinkiewicz--Zygmund inequalities in the case of even moment-orders. Our results are applied to give elementary proofs of the classical central limit theorem (CLT) and of the CLT for the empirical bootstrap. Moreover, we derive moment and exponential inequalities for self-normalized sums.

Go to article

Burrow Morphology Of The Land Crab Gecarcinus Lateralis And The Ghost Crab Ocypode Quadrata On San Salvador Island, The Bahamas: Comparisons And Palaeoenvironmental Implications, Koji Seike, H. Allen Curran Jan 2014

Burrow Morphology Of The Land Crab Gecarcinus Lateralis And The Ghost Crab Ocypode Quadrata On San Salvador Island, The Bahamas: Comparisons And Palaeoenvironmental Implications, Koji Seike, H. Allen Curran

Geosciences: Faculty Publications

Burrow morphologies of the land crab Gecarcinus lateralis and the ghost crab Ocypode quadrata were investigated on East Beach, San Salvador Island, The Bahamas, with the goals of critical comparison of their morphologies and of clarifying and advancing their palaeoenvironmental usefulness. In comparing land crab burrows to those of the ghost crab, the former are simpler but more variable in overall shape. G. lateralis burrows have a more compressed form in the transverse section of the burrow shaft and possess lower (more horizontal) shaft inclination than those of O. quadrata. In the late Holocene backshore and dune deposits on San …

Go to article

Discontinuity Surfaces In Upper Cretaceous To Paleogene Carbonates Of Central Dalmatia (Croatia): Glossifungites Ichnofacies, Biogenic Calcretes, And Stratigraphic Implications, Mihovil Brlek, Tvrtko Korbar, Adrijan Košir, Bosiljka Glumac, Anita Grizelj, Bojan Otoničar Jan 2014

Discontinuity Surfaces In Upper Cretaceous To Paleogene Carbonates Of Central Dalmatia (Croatia): Glossifungites Ichnofacies, Biogenic Calcretes, And Stratigraphic Implications, Mihovil Brlek, Tvrtko Korbar, Adrijan Košir, Bosiljka Glumac, Anita Grizelj, Bojan Otoničar

Geosciences: Faculty Publications

Substrate-controlled ichnofacies and biogenic calcretes represent key features for identification and interpretation of discontinuities in the carbonate rock record, which are of great significance for stratigraphic interpretations and correlations. Intraformational firmground and composite surfaces, as well as a regional Cretaceous to Paleogene (K-Pg) subaerial unconformity, developed in Upper Cretaceous to Paleogene intra-platform peritidal successions in central Dalmatia, Croatia (Adriatic-Dinaridic Carbonate Platform, ADCP), were analyzed for their trace fossil and subaerial exposure features. Thalassinoides (probably T. paradoxicus) box-work burrow systems of the substrate-controlled Glossifungites ichnofacies characterize the two documented firmgrounds and one composite (polygenic) surface. Rhizogenic laminar calcretes developed subsequently inside …

Go to article

Conformal Gravity Holography In Four Dimensions, Daniel Grumiller, Maria Irakleidou, Iva Lovrekovic,, Robert Mcnees Jan 2014

Conformal Gravity Holography In Four Dimensions, Daniel Grumiller, Maria Irakleidou, Iva Lovrekovic,, Robert Mcnees

Physics: Faculty Publications and Other Works

We formulate four-dimensional conformal gravity with (anti–)de Sitter boundary conditions that are weaker than Starobinsky boundary conditions, allowing for an asymptotically subleading Rindler term concurrent with a recent model for gravity at large distances. We prove the consistency of the variational principle and derive the holographic response functions. One of them is the conformal gravity version of the Brown–York stress tensor, the other is a “partially massless response”. The on shell action and response functions are finite and do not require holographic renormalization. Finally, we discuss phenomenologically interesting examples, including the most general spherically symmetric solutions and rotating black hole …

Go to article

Stable Isotopic (Δ13C And Δ18O) Signatures Of Biogenic Calcretes Marking Discontinuity Surfaces: A Case Study From Upper Cretaceous Carbonates Of Central Dalmatia And Eastern Istria, Croatia, Mihovil Brlek, Bosiljka Glumac Jan 2014

Stable Isotopic (Δ13C And Δ18O) Signatures Of Biogenic Calcretes Marking Discontinuity Surfaces: A Case Study From Upper Cretaceous Carbonates Of Central Dalmatia And Eastern Istria, Croatia, Mihovil Brlek, Bosiljka Glumac

Geosciences: Faculty Publications

Biogenic calcretes associated with a regional Cretaceous to Paleogene subaerial unconformity and an intraformational composite (polygenic) surface in Upper Cretaceous intra-platform peritidal successions in central Dalmatia and eastern Istria, Croatia (Adriatic-Dinaridic Carbonate Platform), were analyzed for their δ13C and δ18O signatures in order to provide insight into the conditions of subaerial exposure and calcrete development. The distinctly negative δ13C signatures of biogenic calcretes marking the regional subaerial unconformity differ considerably from the δ13C values of the host marine limestones. This indicates carbon isotope exchange of primary marine CaCO3 with CO2 released by root and rhizomicrobial respiration and subsequent precipitation of …

Go to article

New Carbohydrate-Based Anti-Cancer And Anti-Bacterial Vaccines, Zhifang Zhou Jan 2014

New Carbohydrate-Based Anti-Cancer And Anti-Bacterial Vaccines, Zhifang Zhou

Wayne State University Dissertations

The unique carbohydrates expressed on the surface of cancer, bacterial, viral and fungal cells are excellent target antigens for the design of therapeutic or preventive vaccines. However, as antigens carbohydrates have problems. First, carbohydrates usually have low immunogenicity. Second, even if immunogenic, carbohydrates typically elicit T cell-independent immune responses. To overcome these problems and design useful vaccines based on carbohydrate antigens, they are usually coupled with carrier proteins to form conjugates to enhance the immunogenicity of the antigens. However, there are still some issues existing in glycoprotein vaccines, such as poor reproducibility of the conjugates, difficulties in quality control and …

Go to article

Measurement Of Branching Fractions Of Rare Semi-Leptonic Ds Decays Ds → Π0 L Ν, Ds →Ρ L Ν, Ds →Ks L Ν (Near ϒ (4s), ϒ (5s)) At Belle, Sudeshna Ganguly Jan 2014

Measurement Of Branching Fractions Of Rare Semi-Leptonic Ds Decays Ds → Π0 L Ν, Ds →Ρ L Ν, Ds →Ks L Ν (Near ϒ (4s), ϒ (5s)) At Belle, Sudeshna Ganguly

Wayne State University Dissertations

In Particle physics, a flavor-less meson whose constituents are a quark and an anti-quark is known as quarkonium. Mesons which are formed by a bound state of charm quark and anti-charm quark are known as charmonium states. Different inspections of exotic charmonium states have been understood as 4-quark states. Charmonium states are produced via e+e− annihilation. We search at Belle, based on 119000 tagged events in the ϒ (4S) and ϒ (5S) energy regions, to look for Ds → π0 l ν, Ds →ρ l ν, Ds →Ks l ν ; considering the electron candidates as well the heavy electron …

Go to article

Computational Studies Of Enzymatic Reactions And Inorganic Compounds, Dong Fang Jan 2014

Computational Studies Of Enzymatic Reactions And Inorganic Compounds, Dong Fang

Wayne State University Dissertations

Quantum mechanics (QM) calculations have been demonstrated to give very accurate results in studying a variety of chemical reactions. However, the current computing resources limits its use in large-size systems such as enzymes. Compared to QM, Molecular Mechanics (MM) have an advantage in computing time but disadvantage in accuracy, and MM cannot be used in reactions involving bonding forming and breaking. To combine the advantages of these two types of methods, QM/MM has been introduced to study reactions and processes in large-size systems, and it has been proven to give accurate results with moderate computational expense. When studying enzymatic reactions, …

Go to article

Progress In Zeolite Synthesis Promotes Advanced Applications, Moussa Zaarour, Biao Dong, Izabela Naydenova, Richard Retoux, Svetlana Mintova Jan 2014

Progress In Zeolite Synthesis Promotes Advanced Applications, Moussa Zaarour, Biao Dong, Izabela Naydenova, Richard Retoux, Svetlana Mintova

Articles

This article outlines the importance of zeolite synthesis and their unique physicochemical characteristics promoting advanced applications. The main strategies for preparation of zeolites including organic-template assisted, organic-template free and alternative procedures are considered for synthesis of crystallites offering control and fine-tuning of their properties. Besides, rational design of zeolites with pre-determined structure, porosity, size, morphology, and composition are more viable by studying carefully the chemical and physical parameters controlling the zeolite synthesis and understanding the crystallization mechanism. Finally, a particular attention to the preparation of zeolites with nanosized dimensions and their utilization in innovative applications including photovoltaic, medicine and holographic …

Go to article

Getting Started With Research " Beginning: Defining A Research Question And Preparing A Research Plan, Jacinta Browne Jan 2014

Getting Started With Research " Beginning: Defining A Research Question And Preparing A Research Plan, Jacinta Browne

Articles

Research is the lifeblood of medicine with innovations being made in the different technologies used to diagnose and / or screen for the presence of disease or to deliver treatments with higher efficacy. Scientific publication is the network of vessels which delivers the lifeblood. The outputs of research provides us with tomorrows medicine. In this series of articles we will be discussing the different aspects of carrying out research from the conception of the research idea to publication in a peer reviewed journal with the cycle repeating again with new research ideas emerging from the research conducted.

Go to article

Getting Started With Research "Carrying Out Your Research Project", Jacinta Browne Jan 2014

Getting Started With Research "Carrying Out Your Research Project", Jacinta Browne

Articles

This paper gives an overview of the considerations and practical aspects of carrying out a research project which may be of use to those beginning their research career or simply carrying out a research project for the first time as part of an academic qualification. It outlines practical steps for consideration in the day to day management of a research project and highlights areas which require particular consideration for a project to be completed successfully.

Go to article

Investigation Of The Sensitivity To Humidity Of An Acrylamide-Based Photopolymer Containing N-Phenylglycine As A Photoinitiator, Tatsiana Mikulchyk, Suzanne Martin, Izabela Naydenova Jan 2014

Investigation Of The Sensitivity To Humidity Of An Acrylamide-Based Photopolymer Containing N-Phenylglycine As A Photoinitiator, Tatsiana Mikulchyk, Suzanne Martin, Izabela Naydenova

Articles

Sensitivity of holographic recording materials to the relative humidity (RH) of the environment often restricts their use in fabrication of holographic optical elements and other applications. It is important to develop materials with little or no sensitivity to humidity. In this paper the humidity response of transmission gratings recorded in an acrylamide-based photopolymer containing N-phenylglycine (NPG) as a photoinitiator is studied at RH = 20 – 90 %. The hologram is found to be completely insensitive to humidity at RH below 70 % and its diffraction efficiency remains constant. A decrease in diffraction efficiency is observed at RH = 80 …

Go to article

Study Of ¹⁸Ne Using The Array For Nuclear Astrophysics And Structure With Exotic Nuclei, Laura Pratt Jan 2014

Study Of ¹⁸Ne Using The Array For Nuclear Astrophysics And Structure With Exotic Nuclei, Laura Pratt

LSU Doctoral Dissertations

Reactions involving radioactive nuclei play an important role in stellar explosions, but limited experimental information is available due to difficulties in producing and studying radioactive nuclei. Several facilities aim to provide greater access to these unstable isotopes at higher intensities, but more efficient and selective techniques and devices are required to be able to study many important reactions. The Array for Nuclear Astrophysics and Structure with Exotic Nuclei (ANASEN), a charged particle detector designed by Louisiana State University (LSU) and Florida State University (FSU), was created for this purpose. ANASEN is used to study the reactions important for the αp- …

Go to article

Engineering Collaborations In Medical Modeling And Simulation, Frederic D. Mckenzie, Salim Chemlal, Tom Hubbard, Robert E. Kelly, Roderick C. Borgie, David A. Besachio, Michel Audette Jan 2014

Engineering Collaborations In Medical Modeling And Simulation, Frederic D. Mckenzie, Salim Chemlal, Tom Hubbard, Robert E. Kelly, Roderick C. Borgie, David A. Besachio, Michel Audette

Computational Modeling & Simulation Engineering Faculty Publications

Fifty years ago computer science was just beginning to see common acceptance as a growing discipline and very few universities had a computer science department although other departments were utilizing computers and software to enhance their methodologies. We believe modeling and simulation (M&S) is on a similar path. Many other disciplines utilize M&S to enhance their methodologies but we also believe that M&S fundamentals can be essential in making better decisions by utilizing the appropriate model for the problem at hand, expanding the solution space through simulation, and understanding it through visualization and proper analyses. After our students learn these …

Go to article

Graph Partitioning Using Matrix Values For Preconditioning Symmetric Positive Definite Systems, Eugenr Vecharynski, Yousef Saad, Masha Sosonkina Jan 2014

Graph Partitioning Using Matrix Values For Preconditioning Symmetric Positive Definite Systems, Eugenr Vecharynski, Yousef Saad, Masha Sosonkina

Computational Modeling & Simulation Engineering Faculty Publications

Prior to the parallel solution of a large linear system, it is required to perform a partitioning of its equations/unknowns. Standard partitioning algorithms are designed using the considerations of the efficiency of the parallel matrix-vector multiplication, and typically disregard the information on the coefficients of the matrix. This information, however, may have a significant impact on the quality of the preconditioning procedure used within the chosen iterative scheme. In the present paper, we suggest a spectral partitioning algorithm, which takes into account the information on the matrix coefficients and constructs partitions with respect to the objective of enhancing the quality …

Go to article

Estimating Hydroxyl Radical Photochemical Formation Rates In Natural Waters During Long-Term Laboratory Irradiation Experiments, Luni Sun, Hongmei Chen, Hussain A. Abdulla, Kenneth Mopper Jan 2014

Estimating Hydroxyl Radical Photochemical Formation Rates In Natural Waters During Long-Term Laboratory Irradiation Experiments, Luni Sun, Hongmei Chen, Hussain A. Abdulla, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

In this study it was observed that, during long-term irradiations (>1 day) of natural waters, the methods for measuring hydroxyl radical (˙OH) formation rates based upon sequentially determined cumulative concentrations of photoproducts from probes significantly underestimate actual ˙OH formation rates. Performing a correction using the photodegradation rates of the probe products improves the ˙OH estimation for short term irradiations (<1 day), but not long term irradiations. Only the ‘instantaneous’ formation rates, which were obtained by adding probes to aliquots at each time point and irradiating these sub-samples for a short time (≤2 h), were found appropriate for accurately estimating ˙OH photochemical formation rates during long-term laboratory irradiation experiments. Our results also showed that in iron- and dissolved organic matter (DOM)-rich water samples, ˙OH appears to be mainly produced from the Fenton reaction initially, but subsequently from other sources possibly from DOM photoreactions. Pathways of ˙OH formation in long-term irradiations in relation to H2O2 and iron concentrations are discussed.

Go to article

Retrieval Of Carbon Dioxide Vertical Profiles From Solar Occultation Observations And Associated Error Budgets For Ace-Fts And Cass-Fts, C. E. Sioris, C. D. Boone, R. Nassar, K. J. Sutton, I. E. Gordon, K. A. Walker, P. F. Bernath Jan 2014

Retrieval Of Carbon Dioxide Vertical Profiles From Solar Occultation Observations And Associated Error Budgets For Ace-Fts And Cass-Fts, C. E. Sioris, C. D. Boone, R. Nassar, K. J. Sutton, I. E. Gordon, K. A. Walker, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

An algorithm is developed to retrieve the vertical profile of carbon dioxide in the 5 to 25 km altitude range using mid-infrared solar occultation spectra from the main instrument of the ACE (Atmospheric Chemistry Experiment) mission, namely the Fourier transform spectrometer (FTS). The main challenge is to find an atmospheric phenomenon which can be used for accurate tangent height determination in the lower atmosphere, where the tangent heights (THs) calculated from geometric and timing information are not of sufficient accuracy. Error budgets for the retrieval of CO2 from ACE-FTS and the FTS on a potential follow-on mission named CASS …

Go to article

Derivation Of Tropospheric Methane From Tccon Ch4 And Hf Total Column Observations, K. M. Saad, D. Wunch, P. Bernath, C. Boone, B. Connor, N. M. Deutscher, D.W.T. Griffith, R. Kivi, J. Notholt, C. Roehl, M. Schneider, V. Sherlock, P. O. Wennberg Jan 2014

Derivation Of Tropospheric Methane From Tccon Ch4 And Hf Total Column Observations, K. M. Saad, D. Wunch, P. Bernath, C. Boone, B. Connor, N. M. Deutscher, D.W.T. Griffith, R. Kivi, J. Notholt, C. Roehl, M. Schneider, V. Sherlock, P. O. Wennberg

Chemistry & Biochemistry Faculty Publications

The Total Carbon Column Observing Network (TCCON) is a global ground-based network of Fourier transform spectrometers that produce precise measurements of column-averaged dry-air mole fractions of atmospheric methane (CH4). Temporal variability in the total column of CH4 due to stratospheric dynamics obscures fluctuations and trends driven by tropospheric transport and local surface fluxes that are critical for understanding CH4 sources and sinks. We reduce the contribution of stratospheric variability from the total column average by subtracting an estimate of the stratospheric CH4 derived from simultaneous measurements of hydrogen fluoride (HF). HF provides a proxy for …

Go to article

Methods For The Characterization Of Deep-Sea Benthic Megafauna In The Vicinity Of The Deepwater Horizon Macondo Well, Stephanie Marie Sharuga Jan 2014

Methods For The Characterization Of Deep-Sea Benthic Megafauna In The Vicinity Of The Deepwater Horizon Macondo Well, Stephanie Marie Sharuga

LSU Doctoral Dissertations

Soft-sediment benthic environments are amongst the largest marine ecosystems in the world and play important roles in many ecosystem functions. In recent years, exploitation of resources and unintentional impacts on deep-sea benthic environments has increased. The Deepwater Horizon oil spill of 2010 in the northern Gulf of Mexico (GoM) represented a prime example of this. The oil spill not only highlighted deficiencies of data and information on baseline conditions, but also represented an opportunity to learn more and develop better methods for the future. Deep-sea imaging platforms such as autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROVs) have been …

Go to article

Industrial Wireless Sensor Networks, Shancang Li, Hongjian Sun, Arumugam Nallanathan, Li Xu, Shanshan Zhao, Qindong Sun Jan 2014

Industrial Wireless Sensor Networks, Shancang Li, Hongjian Sun, Arumugam Nallanathan, Li Xu, Shanshan Zhao, Qindong Sun

Information Technology & Decision Sciences Faculty Publications

(First Paragraph) Industrial wireless sensor networks (IWSNs) incorporate wireless sensor networks with intelligent industrial systems providing many advantages over existing industrial applications, such as wireless communication, low cost, rapid deployment, self-organization, intelligent controlling, and processing capability. With the proliferation of wireless sensor networks in industrial applications, IWSNs technologies promise to play a significant role in developing more reliable, efficient, stable, flexible, and application-centric industrial systems.

Go to article

Addressing The Land Loss-Fish Production Paradox, Kristy A. Lewis Jan 2014

Addressing The Land Loss-Fish Production Paradox, Kristy A. Lewis

LSU Doctoral Dissertations

Saltmarsh loss is occurring at high rates in Louisiana (LA), but understanding the impacts that marsh degradation has had on historical abundance of estuarine nekton in Barataria Bay, LA is lacking. I first examined the differences between fishery independent and fishery dependent data as indices of relative abundance. Previous studies used landings data to evaluate the importance of marsh habitat (e.g. distance of marsh edge and area of intertidal marsh) to fisheries production, but for most species, landings and survey data showed differing patterns of abundance through time. These findings emphasize the importance of using survey data (not landings data) …

Go to article

Untangling Earth System Responses Recorded In Sulfate's Sulfur And Oxygen Isotopes At The Dawn Of Multicellular Life And Today, Bryan Alan Killingsworth Jan 2014

Untangling Earth System Responses Recorded In Sulfate's Sulfur And Oxygen Isotopes At The Dawn Of Multicellular Life And Today, Bryan Alan Killingsworth

LSU Doctoral Dissertations

Major Earth system perturbations in the deep past and today are recorded in sulfate sulfur and oxygen isotopes, as examined here in three cases. (1) Sedimentary sulfate record of the “Marinoan Oxygen-17 Depletion” (MOSD) event, implies ultra-high CO2 atmosphere at ~635 Ma after global glaciation. MOSD duration is constrained by correlating its most complete record to radiometric dates. Barium sulfate layers in South China sediments show the MOSD in lower layers but persistently absent up section. Carbon-13 correlation locates the MOSD within dated intervals from other sites, yielding a 0 - 0.99 Myr duration. Thus, sedimentary constraint on this non-steady-state …

Go to article

Concordance Between Phylogeographic And Biogeographic Boundaries In The Coral Triangle: Conservation Implications Based On Comparative Analyses Of Multiple Giant Clam Species, Timery S. Deboer, Maria Rio Abdon Naguit, Mark V. Erdmann, Maria Carmen A. Ablan-Lagman, Ambariyanto, Kent E. Carpenter, Abdul Hamid A. Toha, Paul H. Barber Jan 2014

Concordance Between Phylogeographic And Biogeographic Boundaries In The Coral Triangle: Conservation Implications Based On Comparative Analyses Of Multiple Giant Clam Species, Timery S. Deboer, Maria Rio Abdon Naguit, Mark V. Erdmann, Maria Carmen A. Ablan-Lagman, Ambariyanto, Kent E. Carpenter, Abdul Hamid A. Toha, Paul H. Barber

Biological Sciences Faculty Publications

Marine habitats are in decline worldwide, precipitating a strong interest in marine conservation. The use of biogeographic data to designate ecoregions has had significant impacts on terrestrial conservation efforts. However, classification of marine environments into ecoregions has only become available in the last several years, based on biogeographic data supplemented by geomorphology, ocean currents, and water temperatures. Here we use a comparative phylogeographic approach to test for concordant phylogeographic patterns in three closely related species of Tridacna giant clams across the Coral Triangle, the most biodiverse marine region in the world and one of the most threatened. Data from a …

Go to article

Nonexistent Compounds As A Guide To Innovation, Dean F. Martin, Barbara B. Martin Jan 2014

Nonexistent Compounds As A Guide To Innovation, Dean F. Martin, Barbara B. Martin

Chemistry Faculty Publications

A study of nonexistent compounds can be a useful exercise in gaining insight into the factors that can inhibit innovation. Several reasons are suggested: lack of financial support, disinterest in preparing compounds that lack evident utility, notable synthetic challenges with inadequate rewards, inhibition by well-established contemporary knowledge, and invalid interpolations.

Go to article

Voltage Smoothing With A Capacitor, Martin Copello Jan 2014

Voltage Smoothing With A Capacitor, Martin Copello

Undergraduate Journal of Mathematical Modeling: One + Two

A rectifier is an electrical circuit that converts alternating current to direct current, e.g., a half wave rectifier removes lower valleys of the AC voltage wave. If a capacitor is placed in parallel with a half wave rectifier, the transition from voltage peak to peak is smoothed to closer resemble constant DC voltage. The objective of this project was to model the voltage changes of a half wave rectifier with a parallel capacitor. It was found that the smoothness of the voltage waves increased as the capacitance of the capacitor increased.

Go to article

Why Injecting Fine Dust Into A Tornado Is More Promising Than Injecting Coarse Dust: A Geometric Explanation, Octavio Lerma, Olga Kosheleva, Vladik Kreinovich Jan 2014

Why Injecting Fine Dust Into A Tornado Is More Promising Than Injecting Coarse Dust: A Geometric Explanation, Octavio Lerma, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

One of the promising ways to tame a tornado is to inject dust into it. Somewhat counter-intuitively, injecting coarse dust only makes the tornado stronger, while injecting fine dust can indeed help in the taming. This difference has been explained by a mathematical analysis of the corresponding equations, but (in contrast to the usual physics practice) this mathematical analysis has not yet been accompanied by a simple qualitative physical explanation. We show that such a simple explanation can be obtained if we analyze the problem of taming tornados from the geometric viewpoint.

Go to article

Teaching Complex Numbers In High School, Esperanza Gotoman Chavez Jan 2014

Teaching Complex Numbers In High School, Esperanza Gotoman Chavez

LSU Master's Theses

One of the mathematics standards for high schools stated in the Common Core State Standards Initiative (CCSS, 2010 Appendix A, p. 60) is the understanding of the Complex Number system, performing arithmetic operations with complex numbers, representing complex numbers and their operations on the complex plane, and using complex numbers in polynomial identities and equations. In this thesis, we trace back the history of complex numbers and formulate a set of problems based on the history. The thesis gives a description of the Common Core standards and goals. The exercises based on the history of complex numbers are shown to …

Go to article

Detection Of Seagrass Scars Using Sparse Coding And Morphological Filter, Ender Oguslu, Sertan Erkanli, Victoria J. Hill, W. Paul Bissett, Richard C. Zimmerman, Jiang Li, Charles R. Bostater Jr. (Ed.), Stelios P. Mertikas (Ed.), Xavier Neyt (Ed.) Jan 2014

Detection Of Seagrass Scars Using Sparse Coding And Morphological Filter, Ender Oguslu, Sertan Erkanli, Victoria J. Hill, W. Paul Bissett, Richard C. Zimmerman, Jiang Li, Charles R. Bostater Jr. (Ed.), Stelios P. Mertikas (Ed.), Xavier Neyt (Ed.)

OES Faculty Publications

We present a two-step algorithm for the detection of seafloor propeller seagrass scars in shallow water using panchromatic images. The first step is to classify image pixels into scar and non-scar categories based on a sparse coding algorithm. The first step produces an initial scar map in which false positive scar pixels may be present. In the second step, local orientation of each detected scar pixel is computed using the morphological directional profile, which is defined as outputs of a directional filter with a varying orientation parameter. The profile is then utilized to eliminate false positives and generate the final …

Go to article

First Prev Next Last