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Articles 147151 - 147180 of 302639

Full-Text Articles in Physical Sciences and Mathematics

Density Functional Theory Study Of Dilute Transition Metal Phthalocyanines, Daniel Burrill Jan 2015

Density Functional Theory Study Of Dilute Transition Metal Phthalocyanines, Daniel Burrill

Graduate College Dissertations and Theses

Organometallic (OM) crystals are studied in fields ranging from spintronics to photovoltaics. This thesis focuses on studying a particular class of OM crystals known as transition metal-phthalocyanines (TM-Pc) - a molecular crystal composed of chains of planar OM molecules with a transition metal center and four coordinated pyrrole-aromatic rings joined by nitrogen atoms, similar to porphyrin. The structure resembles a dish rack pattern where the planar TM-Pcs of adjacent chains are oriented nearly perpendicular to each other. While TM-Pcs have been studied for decades due to their interesting optical properties and applications as dyes, there has been recent interest in …

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Gis Analysis Of Brownfield Sites In The City Of Minneapolis, Shreya Vaidya Jan 2015

Gis Analysis Of Brownfield Sites In The City Of Minneapolis, Shreya Vaidya

All Graduate Theses, Dissertations, and Other Capstone Projects

Brownfield sites have many negative ramifications on a local area which includes loss of economy, decline in land use value and potential hazard to human health and the environment. Despite the efforts on redeveloping brownfields, Minnesota Pollution Control Agency (MPCA) claims that over 10,000 known contaminated or potentially contaminated sites remain across Minnesota and thousands are likely to exist but have not been identified and recorded. The objectives of this study are to map the brownfield sites in Minneapolis based on the information provided by the regulatory sources and to categorize and analyze all the sites on the basis of …

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Zebra Mussel (Dreissena Polymorpha) Habitat Associations In Four West-Central Minnesota Lakes, April Rose Londo Jan 2015

Zebra Mussel (Dreissena Polymorpha) Habitat Associations In Four West-Central Minnesota Lakes, April Rose Londo

All Graduate Theses, Dissertations, and Other Capstone Projects

In 1989, zebra mussels (Dreissena polymorpha) were first documented in the land of ten thousand lakes in the Lake Superior Basin at Duluth. Zebra mussels are successful invaders because the species attaches to substrates with byssal threads, can adapt to a wide range of environmental conditions, and has a free-swimming veligers that are easily transported. Although invasive mollusks pose a range of economic and ecological threats to inland waters, our understanding of zebra mussels in Minnesota lakes remains limited. To gain additional information regarding zebra mussel ecology in lake systems, I conducted research in four west-central Minnesota lakes that were …

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Reforestation, Renewal, And The Cost Of Coal: Opposing A Manichean Worldview In Central Appalachia, Elizabeth R. Hansen Jan 2015

Reforestation, Renewal, And The Cost Of Coal: Opposing A Manichean Worldview In Central Appalachia, Elizabeth R. Hansen

Pomona Senior Theses

Surface coal mining is a major form of land change and environmental degradation in Central Appalachia. Traditional mine reclamation iresults in unmanaged, unproductive grasslands that fail to mitigate many of the environmental costs of coal mining and are of minimal use to communities. Forestry reclamation is an alternative reclamation tactic that has the potential to address both environmental and socioeconomic concerns in Central Appalachia. A case study of Laurel Fork Mine in Eastern Kentucky is included.

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Innovation Or Inundation: The Political Economy Of Sea Level Rise In The San Francisco Bay Area, Nicole Quilliam Jan 2015

Innovation Or Inundation: The Political Economy Of Sea Level Rise In The San Francisco Bay Area, Nicole Quilliam

Pomona Senior Theses

Sea levels are rising around the world due to climate change and the rise in greenhouse gas emissions causing an environmental climate crisis. This thesis paper analyzes how sea level rise is affecting the San Francisco Bay Area. It walks through the geographical factors contribute to more severe impacts of sea level rise, potential adaptation strategies, and discusses the economic impacts and political challenges of protecting communities from sea level rise.

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New Atlas Features Corn Belt Farmers' Perspectives On Agriculture And Climate, John Tyndall, J. Gordon Arbuckle, Tonya Haigh, Cody L. Knutson, Lois Wright Morton, Linda Stalker Prokopy, Melissa Widhalm Jan 2015

New Atlas Features Corn Belt Farmers' Perspectives On Agriculture And Climate, John Tyndall, J. Gordon Arbuckle, Tonya Haigh, Cody L. Knutson, Lois Wright Morton, Linda Stalker Prokopy, Melissa Widhalm

Drought Mitigation Center: Faculty Publications

The Farmer Perspectives on Agriculture and Weather Variability in the Corn Belt: A Statistical Atlas is a new publication available online at . The atlas includes maps and tables that make it easy for readers to gauge farmer perspectives within the US Corn Belt. Topics covered include farmer beliefs about climate change, attitudes toward actions in response to increased weather variability, risk perceptions, and experiences with weather extremes. This region-specific information on farmers' climate change and risk beliefs is designed to help Extension personnel tailor the climate adaptation and education programming they offer in their region.

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The Effect Of Basement Fault Reactivation On The Triassic—Recent Geology Of Kurdistan, North Iraq, Caroline M. Burberry Jan 2015

The Effect Of Basement Fault Reactivation On The Triassic—Recent Geology Of Kurdistan, North Iraq, Caroline M. Burberry

Department of Earth and Atmospheric Sciences: Faculty Publications

The Zagros orogenic belt is underlain by a complex faulted Precambrian basement. Major fault trends originating in this basement have been invoked to explain large-scale structural changes along the strike of the orogen, e.g. the development of the Kirkuk Embayment (Kurdistan, Iraq) and the Lurestan Salient (Iran). However, within the Kirkuk Embayment, these structural trends have not previously been considered as an interacting group of faults which are periodically reactivated. This contribution first presents a revised basement fault map for the Kirkuk Embayment, created from interpreted gravity data, existing fault maps and remote sensing lineament analyses. This map is then …

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Temporal And Spatial Variability In Dune Reactivation Across The Nebraska Sand Hills, Usa, Rebecca L. Schmeisser Mckean, Ronald J. Goble, Joseph B. Mason, James Swinehart, David B. Loope Jan 2015

Temporal And Spatial Variability In Dune Reactivation Across The Nebraska Sand Hills, Usa, Rebecca L. Schmeisser Mckean, Ronald J. Goble, Joseph B. Mason, James Swinehart, David B. Loope

Department of Earth and Atmospheric Sciences: Faculty Publications

The Nebraska Sand Hills is a stabilized dune field on the Great Plains of North America. Although it is well known that this dune field, like several others on the Great Plains, last experienced widespread activity during the Medieval Climatic Anomaly (MCA, ~AD 900–1300), spatial variation in the timing and nature of drought development is poorly constrained. To elucidate spatial trends in dune reactivation, samples potentially representing MCA activity across the Sand Hills were collected and dated using optically stimulated luminescence (OSL). Ages from the older part of the MCA were obtained from eolian sediments in the northwestern Sand Hills, …

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Atmospheric Circulation Processes Contributing To A Multidecadal Variation In Reconstructed And Modeled Indian Monsoon Precipitation, Qianru Wu, Qi Hu Jan 2015

Atmospheric Circulation Processes Contributing To A Multidecadal Variation In Reconstructed And Modeled Indian Monsoon Precipitation, Qianru Wu, Qi Hu

Department of Earth and Atmospheric Sciences: Faculty Publications

An analysis of the recently reconstructed gridded May–September total precipitation in the Indian monsoon region for the past half millennium discloses significant variations at multidecadal timescales. Meanwhile, paleo-climate modeling outputs from the National Center for Atmospheric Research Community Climate System Model 4.0 show similar multidecadal variations in the monsoon precipitation. One of those variations at the frequency of 40–50 years per cycle is examined in this study. Major results show that this variation is a product of the processes in that the meridional gradient of the atmospheric enthalpy is strengthened by radiation loss in the high-latitude and polar region. Driven …

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Diatoms At >5000 Meters In The Quelccaya Summit Dome Glacier, Peru, Sherilyn C. Fritz, Bruce E. Brinson, W. E. Billups, Lonnie G. Thompson Jan 2015

Diatoms At >5000 Meters In The Quelccaya Summit Dome Glacier, Peru, Sherilyn C. Fritz, Bruce E. Brinson, W. E. Billups, Lonnie G. Thompson

Department of Earth and Atmospheric Sciences: Faculty Publications

Diatoms were found in late Holocene age ice-core samples recovered from the Quelccaya Summit Dome in the tropical Andes of Peru and were imaged by environmental scanning electron microscopy and identified. Freshwater diatoms in the genera Hantzschia, Pinnularia, and Aulacoseira were the most common taxa in the samples and indicate a freshwater source for the material, which also is suggested by the presence of the freshwater alga Volvox. The overall species composition of the diatoms suggests that the majority of taxa originated from a high-elevation lake or wetland in the cordillera surrounding the ice cap. The abundant …

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The Footprints Of Ancient Co2-Driven Flow Systems: Ferrous Carbonate Concretions Below Bleached Sandstone, David B. Loope, Richard M. Kettler Jan 2015

The Footprints Of Ancient Co2-Driven Flow Systems: Ferrous Carbonate Concretions Below Bleached Sandstone, David B. Loope, Richard M. Kettler

Department of Earth and Atmospheric Sciences: Faculty Publications

Iron-rich carbonates and the oxidized remains of former carbonates (iron-oxide concretions) underlie bleached Navajo Sandstone over large portions of southern Utah. Iron in the carbonates came from hematite rims on sand grains in the upper Navajo that were dissolved when small quantities of methane accumulated beneath the sealing Carmel Formation. As a second buoyant gas (CO2 derived from Oligocene–Miocene magmas) reached the seal and migrated up dip, it dissolved in the underlying water, enhancing the solution’s density. This water carried the released ferrous iron and the methane downward. Carbonates precipitated when the descending, reducing water degassed along fractures. The …

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Diagenetic Incorporation Of Sr Into Aragonitic Bivalve Shells: Implications For Chronostratigraphic And Palaeoenvironmental Interpretations, Maria C. Marcano, Tracy D. Frank, Samuel B. Mukasa, Kyger C. Lohmann, Marco Taviani Jan 2015

Diagenetic Incorporation Of Sr Into Aragonitic Bivalve Shells: Implications For Chronostratigraphic And Palaeoenvironmental Interpretations, Maria C. Marcano, Tracy D. Frank, Samuel B. Mukasa, Kyger C. Lohmann, Marco Taviani

Department of Earth and Atmospheric Sciences: Faculty Publications

Aragonite is easily altered during diagenesis, therefore presumed pristine when present. In effect, beyond polymorphic transformation to calcite, alteration paths of aragonite remain poorly understood despite heavy reliance on such material to produce palaeoenvironmental and chronostratigraphic interpretations. Previous work on core material from Southern McMurdo Sound, Antarctica, showed that unlike their calcitic counterparts, seemingly unaltered aragonite shell fragments invariably produced older than expected 87Sr/86Sr ages. In this study, we pursued additional analyses of these aragonite shells and of the porewater of the core to understand this discrepancy. Aragonite mineralogy was reconfirmed and elemental mapping of shell fragments …

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Negative Feedbacks On Bark Beetle Outbreaks: Widespread And Severe Spruce Beetle Infestation Restricts Subsequent Infestation, Sarah J. Hart, Thomas T. Veblen, Nathan Mietkiewicz, Dominik Kulakowski Jan 2015

Negative Feedbacks On Bark Beetle Outbreaks: Widespread And Severe Spruce Beetle Infestation Restricts Subsequent Infestation, Sarah J. Hart, Thomas T. Veblen, Nathan Mietkiewicz, Dominik Kulakowski

Geography

Understanding disturbance interactions and their ecological consequences remains a major challenge for research on the response of forests to a changing climate. When, where, and how one disturbance may alter the severity, extent, or occurrence probability of a subsequent disturbance is encapsulated by the concept of linked disturbances. Here, we evaluated 1) how climate and forest habitat variables, including disturbance history, interact to drive 2000s spruce beetle (Dendroctonus rufipennis) infestation of Engelmann spruce (Picea engelmannii) across the Southern Rocky Mountains; and 2) how previous spruce beetle infestation affects subsequent infestation across the Flat Tops Wilderness in northwestern Colorado, which experienced …

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Great South Bay, Long Island, New York Summer Water Quality Monitoring Program, Cercom, Molloy University, John Tanacredi Ph.D., Sixto E. Portilla Jan 2015

Great South Bay, Long Island, New York Summer Water Quality Monitoring Program, Cercom, Molloy University, John Tanacredi Ph.D., Sixto E. Portilla

CERCOM Reports

The Center for Environmental Research and Coastal Oceans Monitoring (CERCOM) visits 15 locations in Great South Bay to monitor for dissolved oxygen (DO), pH, salinity, clarity, total and fecal coliforms and temperature. This monitoring program has been conducted for the past 13 years. These parameters are critical in determining long-term water quality conditions in Long Island estuaries. Methodologies for monitoring parameters are provided by the Standard Methods for the Examination of Water and Wastewater 20th Edition (1998). Criteria for determining water quality conditions in marine eco-systems are based on the type of contact (uses) people have with the water system. …

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Small Sample Umpu Equivalence Testing Based On Saddlepoint Approximations, Renren Zhao Jan 2015

Small Sample Umpu Equivalence Testing Based On Saddlepoint Approximations, Renren Zhao

Doctoral Dissertations

"In the first section, we consider small sample equivalence tests for exponentiality. Statistical inference in this setting is particularly challenging since equivalence testing procedures typically require a much larger sample size, in comparison to classical "difference tests", to perform well. We make use of Butler's marginal likelihood for the shape parameter of a gamma distribution in our development of equivalence tests for exponentiality. We consider two procedures using the principle of confidence interval inclusion, four Bayesian methods, and the uniformly most powerful unbiased (UMPU) test where a saddlepoint approximation to the intractable distribution of a canonical sufficient statistic is used. …

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Investigation Of Respiratory And Heart Rate Variability In Hypertensive Patients, Ramazan Aldemi̇r, Mahmut Tokmakçi Jan 2015

Investigation Of Respiratory And Heart Rate Variability In Hypertensive Patients, Ramazan Aldemi̇r, Mahmut Tokmakçi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, in order to examine the effect of respiration on heart rate variability (HRV), signal processing analyses were performed between the signal received from the periodic movement of the chest of respiration and the pulse plethysmograph (PPS) signal, providing the calculation of both the time and frequency behavior of HRV and also including pulse rate information at the same time. Respiration is used as the comparison parameter in both healthy subjects and in hypertensive patients, not only with the time and frequency components of the HRV, but also with the galvanic skin resistance simultaneously taken with body temperature …

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A Hierarchic Approach Based On Swarm Intelligence To Solve The Traveling Salesman Problem, Mesut Gündüz, Mustafa Servet Kiran, Eren Özceylan Jan 2015

A Hierarchic Approach Based On Swarm Intelligence To Solve The Traveling Salesman Problem, Mesut Gündüz, Mustafa Servet Kiran, Eren Özceylan

Turkish Journal of Electrical Engineering and Computer Sciences

The purpose of this paper is to present a new hierarchic method based on swarm intelligence algorithms for solving the well-known traveling salesman problem. The swarm intelligence algorithms implemented in this study are divided into 2 types: path construction-based and path improvement-based methods. The path construction-based method (ant colony optimization (ACO)) produces good solutions but takes more time to achieve a good solution, while the path improvement-based technique (artificial bee colony (ABC)) quickly produces results but does not achieve a good solution in a reasonable time. Therefore, a new hierarchic method, which consists of both ACO and ABC, is proposed …

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Discrete-Time Modeling Of Hamiltonian Systems, Yaprak Yalçin, Leyla Gören Sümer, Salman Kurtulan Jan 2015

Discrete-Time Modeling Of Hamiltonian Systems, Yaprak Yalçin, Leyla Gören Sümer, Salman Kurtulan

Turkish Journal of Electrical Engineering and Computer Sciences

The problem of discrete-time modeling of the lumped-parameter Hamiltonian systems is considered for engineering applications. Hence, a novel gradient-based method is presented, exploiting the discrete gradient concept and the forward Euler discretization under the assumption of the continuous Hamiltonian model is known. It is proven that the proposed discrete-time model structure defines a symplectic difference system and has the energy-conserving property under some conditions. In order to provide alternate discrete-time models, 3 different discrete-gradient definitions are given. The proposed models are convenient for the design of sampled-data controllers. All of the models are considered for several well-known Hamiltonian systems and …

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Mras-Based Sensorless Speed Backstepping Control For Induction Machine, Using A Flux Sliding Mode Observer, Mohamed Moutchou, Ahmed Abbou, Hassan Mahmoudi Jan 2015

Mras-Based Sensorless Speed Backstepping Control For Induction Machine, Using A Flux Sliding Mode Observer, Mohamed Moutchou, Ahmed Abbou, Hassan Mahmoudi

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, an induction machine rotor speed and rotor flux control using a sensorless backstepping control scheme is discussed. The most interesting point of this technique is that it deals with the nonlinearity of a high-order system by using the virtual control variable to make this system simple, and thus the control outputs can be derived step by step through appropriate Lyapunov functions. To avoid the use of a mechanical sensor, the rotor speed estimation is made by an observer using the model reference adaptive system (MRAS) technique; in order to estimate rotor flux, a sliding mode observer is …

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Short-Term Load Forecasting Without Meteorological Data Using Ai-Based Structures, İdi̇l Işikli Esener, Tolga Yüksel, Mehmet Kurban Jan 2015

Short-Term Load Forecasting Without Meteorological Data Using Ai-Based Structures, İdi̇l Işikli Esener, Tolga Yüksel, Mehmet Kurban

Turkish Journal of Electrical Engineering and Computer Sciences

STLF is used in making decisions about economical power generation capacity, fuel purchasing, safety assessment, and power system planning in order to have economical power conditions. In this study, Turkey's 24-hour-ahead load forecasting without meteorological data is studied. ANN, wavelet transform and ANN, wavelet transform and RBF NN, and EMD and RBF NN structures are used in STLF procedures. Local holidays' historical load data are changed into data with normal day characteristics, and the estimation results of these days are not included in error computation. To obtain more accurate results, a regulation on forecasted loads is proposed. Regulated and unregulated …

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An Intelligence-Based Islanding Detection Method Using Dwt And Ann, Mehrdad Heidari, Ghodratollah Seifossadat, Morteza Razaz Jan 2015

An Intelligence-Based Islanding Detection Method Using Dwt And Ann, Mehrdad Heidari, Ghodratollah Seifossadat, Morteza Razaz

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new method based on artificial neural network (ANN) and discrete wavelet transform (DWT) is proposed for electrical islanding detection. Transient signals produced during an event are used in the proposed method. ANN is trained to classify the transient events as islanding and nonislanding. The required features for classifying are extracted through DWT of voltage and current transient signals. The proposed method is then simulated on a medium voltage distribution system of CIGRE with 2 kinds of DGs. Results show that this method can detect electrical islands more rapidly and accurately.

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Continuous-Time Hopfield Neural Network-Based Optimized Solution To 2-Channel Allocation Problem, Zekeri̇ya Uykan Jan 2015

Continuous-Time Hopfield Neural Network-Based Optimized Solution To 2-Channel Allocation Problem, Zekeri̇ya Uykan

Turkish Journal of Electrical Engineering and Computer Sciences

The channel allocation problem in cellular radio systems is NP-complete, and thus its general solution is not known for even the 2-channel case. It is well known that the link gain system matrix (or received-signal power system matrix) of the radio network is (and may be highly) asymmetric, and that as the Hopfield neural network is applied to optimization problems, its weight matrix should be symmetric. The main contribution of this paper is as follows: turning the channel allocation problem into a maxCut graph partitioning problem, we propose a simple and effective continuous-time Hopfield neural network-based solution by determining its …

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Numerical Study Of The Supercritical Solution Of The Stationary Forced Korteweg-De Vries (Sfkdv) Equation, Sumi Dey Jan 2015

Numerical Study Of The Supercritical Solution Of The Stationary Forced Korteweg-De Vries (Sfkdv) Equation, Sumi Dey

Open Access Theses & Dissertations

The time independent surface waves on a two dimensional incompressible and inviscid fluid flow passing over a bump on a flat bottom are considered. The stationary forced Korteweg-de Vries (fKdV) equation is defined in an unbounded interval. In this project, this unbounded interval is considered as three parts - on the bump, left hand side of the bump and right hand side of the bump. Exact boundary conditions are applied to the end points of the bump. All the possible combination of boundary conditions are used. A numerical approach is proposed to find the solitary wave solutions of fKdV equation …

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Operator Calculus Algorithms For Multi-Constrained Paths, Jamila Ben Slimane, Rene' Schott, Ye Qiong Song, G. Stacey Staples, Evangelia Tsiontsiou Jan 2015

Operator Calculus Algorithms For Multi-Constrained Paths, Jamila Ben Slimane, Rene' Schott, Ye Qiong Song, G. Stacey Staples, Evangelia Tsiontsiou

SIUE Faculty Research, Scholarship, and Creative Activity

Classical approaches to multi-constrained routing problems generally require construction of trees and the use of heuristics to prevent combinatorial explosion. Introduced here is the notion of constrained path algebras and their application to multi-constrained path problems. The inherent combinatorial properties of these algebras make them useful for routing problems by implicitly pruning the underlying tree structures. Operator calculus (OC) methods are generalized to multiple non-additive constraints in order to develop algorithms for the multi constrained path problem and multi constrained optimization problem. Theoretical underpinnings are developed first, then algorithms are presented. These algorithms demonstrate the tremendous simplicity, flexibility and speed …

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Clifford Algebra Decompositions Of Conformal Orthogonal Group Elements, G. Stacey Staples, David Wylie Jan 2015

Clifford Algebra Decompositions Of Conformal Orthogonal Group Elements, G. Stacey Staples, David Wylie

SIUE Faculty Research, Scholarship, and Creative Activity

Beginning with a finite-dimensional vector space V equipped with a nondegenerate quadratic form Q, we consider the decompositions of elements of the conformal orthogonal group COQ(V), defined as the direct product of the orthogonal group OQ(V) with dilations. Utilizing the correspondence between conformal orthogonal group elements and ``decomposable'' elements of the associated Clifford algebra, ClQ(V), a decomposition algorithm is developed. Preliminary results on complexity reductions that can be realized passing from additive to multiplicative representations of invertible elements are also presented with examples. The approach here is …

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On Some Recent Experimental Results Concerning Turbulent Coanda Wall Jets, Caroline P. Lubert Jan 2015

On Some Recent Experimental Results Concerning Turbulent Coanda Wall Jets, Caroline P. Lubert

Department of Mathematics and Statistics - Faculty Scholarship

The Coanda effect is the tendency of a stream of fluid to stay attached to a convex surface, rather than follow a straight line in its original direction. As a result, in such jets mixing takes place between the jet and the ambient air as soon as the jet issues from its exit nozzle, causing air to be entrained. This air-jet mixture adheres to the nearby surface. Whilst devices employing the Coanda effect usually offer substantial flow deflection, and enhanced turbulence levels and entrainment compared with conventional jet flows, these prospective advantages are generally accompanied by significant disadvantages including a …

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Architectural Acoustical Oddities, Zev C. Woodstock, Caroline P. Lubert Jan 2015

Architectural Acoustical Oddities, Zev C. Woodstock, Caroline P. Lubert

Department of Mathematics and Statistics - Faculty Scholarship

This paper offers a review of two types of acoustic oddity caused by periodic architecture. These periodic structures of interest are brick plazas and staircases with special dimensions. When an observer stands by one of these periodic structures and produces a percussive white noise, a high-pitched sound can be heard. The frequency of the returned sound is unrelated to the initial sound, and completely determined by the architecture of the structures themselves. This phenomenon is called repetition pitch. Comparative work done at James Madison University is offered to show the relationship between brick plazas at JMU and the repetition pitch …

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A Stable Wavelength-Spacing-Tunable Dual-Wavelength Single-Longitudinal-Mode Fiber Ring Laser Based On A Dmd Filter, Tao Wang, Gang Liu, Su-Hua Zhou, Hui-Chun Yang, Bin-Bin Yan, Xiao Chen, Chong-Xiu Yu, Xin-Zhu Sang, Feng Xiao, Kamal Alameh Jan 2015

A Stable Wavelength-Spacing-Tunable Dual-Wavelength Single-Longitudinal-Mode Fiber Ring Laser Based On A Dmd Filter, Tao Wang, Gang Liu, Su-Hua Zhou, Hui-Chun Yang, Bin-Bin Yan, Xiao Chen, Chong-Xiu Yu, Xin-Zhu Sang, Feng Xiao, Kamal Alameh

Research outputs 2014 to 2021

A stable single-longitudinal-mode dual-wavelength( SLM-DW) multiple ring fiber laser with a tunable wavelength spacing was proposed and demonstrated. In the multiple ring cavities, the mode selection is made by the tunable digital micro-mirror device( DMD) filter and two different length passive sub-ring cavities. The DMD filter can select and couple any two wavelengths from the gain spectrum of the erbium-doped fiber( EDF). The SLM lasing is guaranteed by the two sub-ring cavities which serve as a mode filter. The stable and uniform dual wave length oscillation is obtained by the highly-nonlinear photonic crystal fiber( HN-PCF),which can generate the four-wave-mixing( FWM) …

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Combining Semiparametric Regression And Kriging For Prediction Of Pm2.5 Pollutant Levels At Unmonitored Locations With Meterological And Traffic Data, Justin Jonathan Strate Jan 2015

Combining Semiparametric Regression And Kriging For Prediction Of Pm2.5 Pollutant Levels At Unmonitored Locations With Meterological And Traffic Data, Justin Jonathan Strate

Open Access Theses & Dissertations

Particulate matter (PM) is defined by the Texas Commission on Environmental Quality (TCEQ) as "a mixture of solid particles and liquid droplets found in the air". These particles vary widely in size. Those particles that are less than 2.5 micrometers in aerodynamic diameter are known as Particulate Matter 2.5 or PM2.5. These particles are inhaled, and their health effects are still largely being studied. Past studies have assessed PM2.5 exposure of a population, yet individual exposure is more diffcult to assess and may vary widely in a population. Recent studies have combined semiparametric models with kriging (Li et. al [2012]) …

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A Bayes Approach In Step-Stress Accelerated Life Testings, Hao Yang Teng Jan 2015

A Bayes Approach In Step-Stress Accelerated Life Testings, Hao Yang Teng

Open Access Theses & Dissertations

A Bayesian analysis for the Weibull proportional hazard (PH) model is presented. A comparison between the Weibull PH model and the Weibull cumulative exposure (CE) model is made graphically and mathematically. The PH model is as flexible as the CE model in fitting step-stress data and the mathematical form of the PH model enables researchers to do Bayesian inferencemuch easier than the CE model. In addition, the PH model has the desirable proportional hazard property. A convex tent prior is used for Bayesian analysis. Markov chain Monte Carlo methods are used for posterior inferences. In this study, we adopt two …

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