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2015

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Articles 5431 - 5460 of 7525

Full-Text Articles in Engineering

An Investigation Of The Covariations Between Variations In Exhaled Carbon Dioxide And Cerebral Blood Flow Levels During Apnea, Varun Ajay Kanal Jan 2015

An Investigation Of The Covariations Between Variations In Exhaled Carbon Dioxide And Cerebral Blood Flow Levels During Apnea, Varun Ajay Kanal

Bioengineering Theses - Archive

Sleep apnea is a breathing disorder characterized by repetitive reduction or cessation of breathing during sleep. It is estimated that that around 17% of adults suffer from mild to severe sleep disordered breathing. The aim of this study was to investigate the level of correlation between variations in exhaled CO2 and cerebral blood flow (CBF) during apnea. It is difficult to measure the CBF during sleep. This relationship was found in an effort to substitute the measurement of the changes in CBF with the changes in the CO2. The relationship between these two physiological parameters was first studied in healthy …

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Two-Stage Stochastic Programming In Adaptive Interdisciplinary Pain Management, Na Wang Jan 2015

Two-Stage Stochastic Programming In Adaptive Interdisciplinary Pain Management, Na Wang

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Chronic pain is a global health problem. About 100 million adult Americans suffering from chronic pain, which costs $560 - $635 billion per year. The Eugene McDermott Center for Pain Management at the University of Texas Southwestern Medical Center at Dallas conducted a two-stage pain management program for patients who suffer from chronic pain. Data information such as patient’s parameter, past treatment, pain outcome at different evaluation point and so on has been collected by the McDermott Center. The University of Texas at Arlington is collaborating with the McDermott Center to find optimal treatment strategies for individual patients.A treatment strategy …

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High-Dimensional Adaptive Dynamic Programming With Mixed Integer Linear Programming, Zirun Zhang Jan 2015

High-Dimensional Adaptive Dynamic Programming With Mixed Integer Linear Programming, Zirun Zhang

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Dynamic programming (DP, Bellman 1957) is a classic mathematical programming approach to solve multistage decision problems. The “Bellman equation” uses a recursive concept that includes both the current contribution and future contribution in the objective function of an optimization. The method has potential to represent dynamic decision-making systems, but an exact DP solution algorithm is limited to small problems with restrictions, such as problems with linear transitions and problems without uncertainty. Approximate dynamic programming (ADP) is a modern branch of DP that seeks to achieve numerical solutions via approximation. It is can be applied to real-world DP problems, but there …

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Performance Characteristics Of Single Effect Lithium Bromide/ Water Absorption Chiller For Small Data Centers, Abhishek Arun Babu Mysore Jan 2015

Performance Characteristics Of Single Effect Lithium Bromide/ Water Absorption Chiller For Small Data Centers, Abhishek Arun Babu Mysore

Mechanical and Aerospace Engineering Theses - Archive

A medium data center consists of servers performing operations such as file sharing, collaboration and email. There are a large number of small and medium data centers across the world which consume more energy and are less efficient when compared to large data center facilities of companies such as GOOGLE, APPLE and FACEBOOK. Such companies are making their data center facilities more environmental friendly by employing renewable energy solutions such as wind and solar to power the data center or in data center cooling. This not only reduces the carbon footprint significantly but also decreases the costs incurred over a …

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Chip Package Interaction Study To Analyze The Mechanical Integrity Of A 3-D Tsv Package, Pavan Rajmane Jan 2015

Chip Package Interaction Study To Analyze The Mechanical Integrity Of A 3-D Tsv Package, Pavan Rajmane

Mechanical and Aerospace Engineering Theses - Archive

The convergence and miniaturization of computing and communications dictates building up rather than out. As planar device miniaturization continues to its ultimate limits, the complexity of circuit interconnections for 2-D devices becomes a limitation for performance and drives up power dissipation [1]. As the consumers demand more functions on their hand-held electronic devices, the need for more devices such as memory, CPU and GPU in hand-held type footprints is increasing. Chip-stacking (3-D) is emerging as a powerful tool that satiates such IC package requirements. A 3-D FPGA would overcome the interconnect limitations, resulting in greater silicon efficiency per function (number …

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Experimental Study Of Quaternary Nitrate/Nitrite Molten Salt As Advanced Heat Transfer Fluid And Energy Storage Material In Concentrated Solar Power Plant, Sumeet Changla Jan 2015

Experimental Study Of Quaternary Nitrate/Nitrite Molten Salt As Advanced Heat Transfer Fluid And Energy Storage Material In Concentrated Solar Power Plant, Sumeet Changla

Mechanical and Aerospace Engineering Theses - Archive

Solar energy is used to produce electricity by two methods namely photovoltaic and concentrated solar power plant systems. Concentrated Solar power plants hold a distinct advantage over photovoltaic, which is that of energy storage. Energy can be stored in thermal energy storage system during day time and can be used to dispatch energy during peak demand and during raining or cloudy days to produce electricity. All concentrated solar power plants in operation use sensible heat storage method to store energy. Sensible heat storage system have been used in industry owing to ease of dispatch ability. Currently a binary mixture of …

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Impact Of Viscoelastic Material Characterization Of Pcb's On Thermomechanical Properties Of Qfn Thick Package Under Thermal Cycling, Karthik Rajashekar Jan 2015

Impact Of Viscoelastic Material Characterization Of Pcb's On Thermomechanical Properties Of Qfn Thick Package Under Thermal Cycling, Karthik Rajashekar

Mechanical and Aerospace Engineering Theses - Archive

The QFN component package is a quad flat pack (QFP) with “no-leads”, where the electrical contact to the printed circuit board (PCB) is made through soldering of the lands underneath the package body rather than the traditional leads formed along the perimeter. The popularity of this device package style is primarily due to the superior electrical and thermal performance demonstrated. It is one of the most cutting-edge technologies emerged in the market, exhibiting high performance with unparalleled cost effectiveness. But using thick PCBs (>3mm) is detrimental to the package reliability. The motivation of this work is to understand and …

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Liquid Cooling Of A High-Power Multi-Chip Module Using A Sectioned Cold Plate, Ananthavijayan Sridhar Jan 2015

Liquid Cooling Of A High-Power Multi-Chip Module Using A Sectioned Cold Plate, Ananthavijayan Sridhar

Mechanical and Aerospace Engineering Theses - Archive

With the advancement in micro-fabrication techniques and high performance chips, the heat flux generated through these electronics is reaching a point where air-cooling of these devices is not efficient enough. By definition, Multi-Chip Modules (MCMs) are specialized electronic packages where multiple Integrated-Circuits (ICs) and semiconductor dies are unified onto a single substrate. Increasing advancements in ICs enable MCMs as alternate packaging finding its application in high power electronics like power generation and cooling, medical devices, lasers and, military electronics etc. Hence, liquid cooling techniques are explored as possible solutions. In this study, a high power MCM is considered and, its …

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A Critical Realist Approach To Engineering Ethics, Eddie Conlon Jan 2015

A Critical Realist Approach To Engineering Ethics, Eddie Conlon

Conference papers

This paper is focused on the teaching of engineering ethics (EE). Through a focus on safety and the lens of what sociologists call the agency/ structure relationship it examimes various approaches to this teaching. Drawing on Critical Realism it argues there are deficiencies in both the dominant approach and a number of proposed alternatives as they suffer from various forms of conflationism . By drawing on Critical Realism (CR) a more robust agenda for teaching engineering ethics can be developed. It is argued that CR offers a basis for understanding the range of factors which lead to accidents and disasters. …

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Study Of The Effect Of Ion Concentration, Ph, And Surface Charge On Single-Particle Placement, Kunhua Yu Jan 2015

Study Of The Effect Of Ion Concentration, Ph, And Surface Charge On Single-Particle Placement, Kunhua Yu

Material Science and Engineering Theses - Archive

Supervising Professor: Seong Jin Koh Single particle placement (SPP) in which nanoparticles are placed on exact substrate positions on a single particle level has drawn a lot of attention as it can be used as an effective tool for bottom-up fabrications of nanoscale systems. In SPP, single nanoparticles are electrically guided toward substrate target positions through electrostatic funneling mechanism and once a single nanoparticle is placed on a target position it prevents the other nanoparticles from approaching toward the substrate, leading to placement of exactly one nanoparticle on each target position. This thesis investigates the role of three key parameters …

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Effect Of Termite Gut Microbe Tav5 On Methane Production From Municipal Solid Waste Degradation, Hoda Rahimi Jan 2015

Effect Of Termite Gut Microbe Tav5 On Methane Production From Municipal Solid Waste Degradation, Hoda Rahimi

Civil Engineering Theses - Archive

Methane from anaerobic processes is being increasingly utilized as an alternative energy source in developed countries, via large projects that extract methane from landfills or wastewater treatment plants. Anaerobic degradation of organic material (biomass) involves decomposition by bacteria under humid conditions without any oxygen. Organic carbon deposited in landfills is converted by microbes to carbon dioxide (CO2) and methane (CH4). If the methane is not captured, it contributes to climate change (25 times more effectively than CO2 on a per-mass basis). If the methane is captured, it can be used as a renewable energy resource. Lignocellulose comprises a significant portion …

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A New Technique For The Estimation Of The Elastic Moduli Of Pavement Layers From Light Weight Deflectometer Data, Nickey Akbariyeh Jan 2015

A New Technique For The Estimation Of The Elastic Moduli Of Pavement Layers From Light Weight Deflectometer Data, Nickey Akbariyeh

Civil Engineering Theses - Archive

This study developed a method to estimate the elastic moduli of a flexible pavement system from Light Weight Deflectometer deflection data. The forward method (simple equations) can be easily programmed into the data acquisition device of the Light Weight Deflectometers. The equations can be of a primary assistance in the evaluation of the flexible pavement structures. The method is simple and it eliminates the need for the backcalculation procedure after the LWD test. The pavement systems considered in this study are composed of 2 to 4 inches of the asphalt concrete wearing layer and 4 to 8 inches of compacted …

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Potential Applicability Of Stress Wave Velocity Method On Pavement Base Materials As A Non-Destructive Testing Technique, Masrur Mahedi Jan 2015

Potential Applicability Of Stress Wave Velocity Method On Pavement Base Materials As A Non-Destructive Testing Technique, Masrur Mahedi

Civil Engineering Theses - Archive

Aggregates derived from natural sources have been used traditionally as the pavement base materials. But in recent times, the extraction of these natural aggregates has be-come more labor intensive and costly due to resource depletion and environmental concerns. Thus, the uses of recycled aggregates as the supplementary of natural aggregates are increasing considerably in pavement construction. Use of recycled aggregates such as recycled crushed concrete (RCA) and recycled asphalt pavement (RAP) reduces the rate of natural resource depletion, construction debris and cost. Although recycled aggregates could be used as a viable alternative of conventional base materials, strength characteristics and product …

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Fatigue Life Assessment Of A Critical Field Welded Connection On A Temporary Railway Bridge Span, Curtis Heinsen Jan 2015

Fatigue Life Assessment Of A Critical Field Welded Connection On A Temporary Railway Bridge Span, Curtis Heinsen

Civil Engineering Theses - Archive

There is a need in the railway industry for a flexible solution to the problem of service interruptions due to impacts on railway bridges from highway and other vehicle traffic. One such solution is the placement of a temporary span that can be used on multiple substructure types and configurations and can be quickly assembled from a kit of available parts. In order to minimize the erection time and maximize the span flexibility such a span could utilize welded connections in place of bolted connections throughout the structure. These connections would be vulnerable to fatigue failure which has been shown …

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Factors Influencing The Microbial Calcium Carbonate Precipitation Performance In Sands, Naga Venkata Prasanna Kumar Velpuri Jan 2015

Factors Influencing The Microbial Calcium Carbonate Precipitation Performance In Sands, Naga Venkata Prasanna Kumar Velpuri

Civil Engineering Theses - Archive

Microbial induced calcium carbonate precipitation is relatively a new ground improvement technique for geotechnical engineers. This technique uses non-pathogenic organisms that are found naturally in soil environment to cement sand particles together at their contacts. This thesis describes the influence of various factors on cementation of MICP-treated soil catalyzed by bacteria and urease from an experimental study. Some of these factors include number of nutrient cycles, concentration of calcium chloride solutions, number of injections and particle size. Finally the objective of my research is to have a better understanding about the effects of various parameters on the biological cementation. Ottawa …

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Testing, Analysis And Classification Of No-Dig Manhole Rehabilitation Materials, Alimohammad Entezarmahdi Jan 2015

Testing, Analysis And Classification Of No-Dig Manhole Rehabilitation Materials, Alimohammad Entezarmahdi

Civil Engineering Theses - Archive

Gravity flow wastewater collection systems are comprised of sewer pipes and manholes. Failure of a manhole may have catastrophic consequences such as developing a sinkhole in the street and roadway, and at a minimum, wastewater flow will be blocked and stream of the manhole will backup causing a sanitary sewer overflow (SSO). Improving structural conditions of a manhole is critical to minimize these types of failures. This thesis considers the impact of several lining materials including cement mortar, epoxy, polyurethane, cured-in-place composites, and a multi- layer structure material on increasing the structural capabilities of deteriorated manholes. The tasks included in …

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Development Of The Duplicate Shear Test For Asphalt Mixtures, Mohammadreza Khajeh Hosseini Jan 2015

Development Of The Duplicate Shear Test For Asphalt Mixtures, Mohammadreza Khajeh Hosseini

Civil Engineering Theses - Archive

Permanent shear deformation is the main cause of rutting in asphalt concrete layers. Therefore, the determination of the shear properties of asphalt mixtures is helpful for predicting the rutting in asphalt pavement structures and for the identification of poor performing asphalt mixtures. The objective of this study was to develop a new test device to replicate similar loading conditions and constraints of the Superpave Shear Tester (SST). The new device, named the Double Shear Tester (DST), determines the mechanical average of the shear properties and responses of two specimens instead of that of a single specimen as in the SST …

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Packaged Silica And Chalcogenide Microspheres And Their Applications For Telecommunications, Pengfei Wang Jan 2015

Packaged Silica And Chalcogenide Microspheres And Their Applications For Telecommunications, Pengfei Wang

Conference papers

To investigate, both theoretically and experimentally, packaged silica and chalcogenide microsphere and their potential applications in telecommunications.

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A New Methodology For Evaluating The Effectiveness Of Bus Rapid Transit Strategies, Ahmad Alomari Jan 2015

A New Methodology For Evaluating The Effectiveness Of Bus Rapid Transit Strategies, Ahmad Alomari

Electronic Theses and Dissertations

Over the last few years, public transportation has become more desirable as capacity of existing roadways failed to keep up with rapidly increasing traffic demand. Buses are one of the most common modes of public transportation with low impact on network capacity, especially in small and congested urban areas. However, the use of regularly scheduled buses as the main public transport mode can become useless with the presence of traffic congestion and dense construction areas. In cases like these, innovative solutions, such as bus rapid transit (BRT), can provide an increased level of service without having to resort to other, …

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The Experience Of Physical And Social Presence In A Virtual Learning Environment As Impacted By The Affordance Of Movement Enabled By Motion Tracking, Aleshia Hayes Jan 2015

The Experience Of Physical And Social Presence In A Virtual Learning Environment As Impacted By The Affordance Of Movement Enabled By Motion Tracking, Aleshia Hayes

Electronic Theses and Dissertations

This research synthesizes existing research findings that social presence (sense of connection with others) and physical presence (sense of being there) increase learning outcomes in Virtual Learning Environments (VLEs) with findings that traditional motion tracking of participants wearing head mounted displays in virtual reality increases both physical and social presence. This information suggests that motion tracking in mixed reality VLEs has a positive impact on social presence and on physical presence. For this study, the affordance of free movement among virtual objects is enabled by Microsoft Kinect tracking of the user's position that is translated to movement of the virtual …

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Broadband Coherent Perfect Absorption In One-Dimensional Optical Systems, Massimo Maximilian Villinger Jan 2015

Broadband Coherent Perfect Absorption In One-Dimensional Optical Systems, Massimo Maximilian Villinger

Electronic Theses and Dissertations

Absorption plays a critical role in a variety of optical applications – sometimes it is desirable to minimize it as in optical fibers and waveguides, or to enhance it as in solar cells and photodetectors. We describe here a new optical scheme that controllably produces high optical absorption over a broad wavelength range (hundreds of nm) in systems that have low intrinsic absorption over the same range. This effect, 'coherent perfect absorption' or CPA, arises from a subtle interplay between interference and absorption of two beams incident on a weakly absorbing medium. In the first part of this study, we …

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Investigating The Influence Of Professional Development On Teacher Perceptions Of Engineering Self Efficacy, Stephen D. Marquis Phd Jan 2015

Investigating The Influence Of Professional Development On Teacher Perceptions Of Engineering Self Efficacy, Stephen D. Marquis Phd

All Student Scholarship

This mixed-methods study examines the influence of a professional-development intervention to support educators in the integration of engineering education at the elementary level. Particular consideration focused on the evolution of teachers' perceptions of engineering self-efficacy following engagement in professional development intended to support the introduction of engineering in selected grade-five classrooms.

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Planar Laser Induced Fluorescence Experiments And Modeling Study Of Jets In Crossflow At Various Injection Angles, Luke Thompson Jan 2015

Planar Laser Induced Fluorescence Experiments And Modeling Study Of Jets In Crossflow At Various Injection Angles, Luke Thompson

Electronic Theses and Dissertations

Planar Laser Induced Fluorescence (PLIF) with acetone seeding was applied to measure the scalar fields of an axisymmetric freejet and an inclined jet-in-crossflow as applicable to film cooling. From the scalar fields, jet-mixing and trajectory characteristics were obtained. In order to validate the technique, the canonical example of a nonreacting freejet of Reynolds Numbers 900-9000 was investigated. Desired structural characteristics were observed and showed strong agreement with computational modeling. After validating the technique with the axisymmetric jet, the jet-in-crossflow was tested with various velocity ratios and jet injection angles. Results indicated the degree of wall separation for different injection angles …

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The Relationship Between Dna's Physical Properties And The Dna Molecule's Harmonic Signature, And Related Motion In Water--A Computational Investigation, Victor Boyer Jan 2015

The Relationship Between Dna's Physical Properties And The Dna Molecule's Harmonic Signature, And Related Motion In Water--A Computational Investigation, Victor Boyer

Electronic Theses and Dissertations

This research investigates through computational methods whether the physical properties of DNA contribute to its harmonic signature, the uniqueness of that signature if present, and motion of the DNA molecule in water. When DNA is solvated in water at normal 'room temperature', it experiences a natural vibration due to the Brownian motion of the particles in the water colliding with the DNA. The null hypothesis is that there is no evidence to suggest a relationship between DNA's motion and strand length, while the alternative hypothesis is that there is evidence to suggest a relationship between DNA's vibrational motion and strand …

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Integrated Sustainability Assessment Framework For The U.S. Transportation, Nuri Onat Jan 2015

Integrated Sustainability Assessment Framework For The U.S. Transportation, Nuri Onat

Electronic Theses and Dissertations

This dissertation aims to investigate the sustainability impacts of alternative vehicle technologies and develop comprehensive sustainability assessment frameworks to analyze potential impacts of these vehicles in the U.S. In order to assess sustainability impact of vehicle alternatives, life-cycle based models has been extensively used in the literature. Although life cycle-based models are often used for environmental impacts of alternative vehicles, analysis of social and economic impacts of these vehicles has gained a tremendous interest. In this regard, there is a growing interest among the international platform and academia to use the Life Cycle Sustainability Assessment framework to have more informed …

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Traffic Conflict Analysis Under Fog Conditions Using Computer Simulation, Binya Zhang Jan 2015

Traffic Conflict Analysis Under Fog Conditions Using Computer Simulation, Binya Zhang

Electronic Theses and Dissertations

The weather condition is a crucial influence factor on road safety issues. Fog is one of the most noticeable weather conditions, which has a significant impact on traffic safety. Such condition reduces the road's visibility and consequently can affect drivers' vision, perception, and judgments. The statistical data shows that many crashes are directly or indirectly caused by the low-visibility weather condition. Hence, it is necessary for road traffic engineers to study the relationship of road traffic accidents and their influence factors. Among these factors, the traffic volume and the speed limits in poor visibility areas are the primary reasons that …

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Analysis Of Steady State Micro-Droplet Evaporation To Enhance Heat Dissipation From Tiny Surfaces., Harish Voota Jan 2015

Analysis Of Steady State Micro-Droplet Evaporation To Enhance Heat Dissipation From Tiny Surfaces., Harish Voota

Electronic Theses and Dissertations

Experimental investigations and numerical predictions of steady state microdroplet evaporation experiments are presented. Steady state droplet evaporation experiments are conducted to understand (1) Droplet contact line influence on evaporation rate efficiency, (2) Droplet contact angle correlation to evaporation rate and (3) Substrate cooling. Experiments are performed on a polymer substrate with a moat like trench (laser patterned) to control droplet contact line dynamics. A bottom-up methodology is implemented for droplet formation on the patterned substrate. Droplet evaporation rates on substrate temperatures 22°C≤ ∆TSubstrate ≤75°C and contact angles 80°≤ Θ ≤110° are measured. For a pinned microdroplet (CCR), volumetric infuse rate …

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Parallel Distributed Discrete Event Simulation Optimization Using Complexity And Deep Learning, Edwin Cortes Jan 2015

Parallel Distributed Discrete Event Simulation Optimization Using Complexity And Deep Learning, Edwin Cortes

Electronic Theses and Dissertations

Parallel distributed discrete event simulation (PDDES) is the execution of a discrete event simulation on a tightly or loosely coupled computer system with multiple processors. The discrete-event simulation model is decomposed into several logical processors (LPs) or simulation objects that can be executed concurrently using partitioning types such as spatial and temporal. PDDES is exceedingly important for the reduction of the simulation time, increase of model size, intellectual property issue mitigation in multi-enterprise simulations, and the sharing of resources. One of the problems with PDDES is the time management to provide flow control over event processing, the process flow, and …

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An Investigation Of Physiological Measures In A Marketing Decision Task, Nelson Lerma Jan 2015

An Investigation Of Physiological Measures In A Marketing Decision Task, Nelson Lerma

Electronic Theses and Dissertations

The objective of the present study was to understand the use of physiological measures as an alternative to traditional market research tools, such as self-reporting measures and focus groups. For centuries, corporations and researchers have relied almost exclusively on traditional measures to gain insights into consumer behavior. Oftentimes, traditional methods have failed to accurately predict consumer demand, and this has prompted corporations to explore alternative methods that will accurately forecast future sales. One the most promising alternative methods currently being investigated is the use of physiological measures as an indication of consumer preference. This field, also referred to as neuromarketing, …

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Response Of Streamflow And Sediment Loading In The Apalachicola River, Florida To Climate And Land Use Land Cover Change, Paige Hovenga Jan 2015

Response Of Streamflow And Sediment Loading In The Apalachicola River, Florida To Climate And Land Use Land Cover Change, Paige Hovenga

Electronic Theses and Dissertations

Located in Florida's panhandle, the Apalachicola River is the southernmost reach of the Apalachicola-Chattahoochee-Flint (ACF) River basin. Streamflow and sediment drains to Apalachicola Bay in the Northern Gulf of Mexico, directly influencing the ecology of the region, in particular seagrass and oyster production. The objective of this study is to evaluate the response of runoff and sediment loading in the Apalachicola River under projected climate change scenarios and land use / land cover (LULC) change. A hydrologic model using the Soil Water Assessment Tool (SWAT) was developed for the Apalachicola region to simulate daily discharge and sediment load under present …

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