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Articles 1081 - 1110 of 4566

Full-Text Articles in Engineering

Investigation Of Oxy-Fuel Combustion Behind Reflected Shockwaves, Owen Pryor Jan 2018

Investigation Of Oxy-Fuel Combustion Behind Reflected Shockwaves, Owen Pryor

Electronic Theses and Dissertations

Supercritical carbon dioxide has brought about new questions on the chemical kinetics of several small hydrocarbon fuels and the effects of carbon dioxide as the primary diluent on the different fuels. This report presents work on the ignition delay times and several species time-histories of methane, ethylene and syngas over a range of conditions. All experiments were conducted behind reflected shock waves using two different shock tubes. The ignition delay times were measured using a GaP photodetector to measure the emission of light. The species time-histories were measured using single laser spectroscopy. The effect of CO2 as a diluent on …

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Bio-Inspired Visual Servo Control Of A Picking Mechanism In An Agricultural Ground Robot, Sinem Gozde Defterli Jan 2018

Bio-Inspired Visual Servo Control Of A Picking Mechanism In An Agricultural Ground Robot, Sinem Gozde Defterli

Electronic Theses and Dissertations

For a recently constructed disease detection agricultural ground robot, the segregation of unhealthy leaves from strawberry plants is a major task of the robot's manipulation subsystem in field operations. In this dissertation, the motion planning of a custom-designed picking mechanism in the ground robot's subsystem is studied in two sections. First, a set of analytical, suboptimal semi-analytical and numerical algorithms are studied to solve the inverse kinematics problem of the handling mechanism in firm circumstances. These premeditated approaches are built on the computation of the joint variables by an identified 3D position data of the target leaf only. The outcomes …

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Evaluating Hydrologic Fluxes Through Stormwater Treatment Systems: Implication To Freshwater Springs In A Karst Environment, Nyle Rice Jan 2018

Evaluating Hydrologic Fluxes Through Stormwater Treatment Systems: Implication To Freshwater Springs In A Karst Environment, Nyle Rice

Electronic Theses and Dissertations

In recent years, concentrations of nutrients such as nitrogen and phosphorus have increased in surface and groundwater resources, due in part to non-point source pollution associated with stormwater runoff. The elevated nutrient concentrations found in stormwater runoff have prompted the design of best management practices (BMP's) to mitigate the problem. The overall objective within this thesis is to analyze the performance of innovative surface BMPs and investigate connections between the BMPs and groundwater flows to freshwater springs within a karst environment. The performance of two stormwater BMPs, blanket filters and vertical reactors containing Bio-sorption Activated Media (BAM), are assessed in …

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Safety Investigation Of Traffic Crashes Incorporating Spatial Correlation Effects, Khalid Alkahtani Jan 2018

Safety Investigation Of Traffic Crashes Incorporating Spatial Correlation Effects, Khalid Alkahtani

Electronic Theses and Dissertations

One main interest in crash frequency modeling is to predict crash counts over a spatial domain of interest (e.g., traffic analysis zones (TAZs)). The macro-level crash prediction models can assist transportation planners with a comprehensive perspective to consider safety in the long-range transportation planning process. Most of the previous studies that have examined traffic crashes at the macro-level are related to high-income countries, whereas there is a lack of similar studies among lower- and middle-income countries where most road traffic deaths (90%) occur. This includes Middle Eastern countries, necessitating a thorough investigation and diagnosis of the issues and factors instigating …

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Analysis Of Heat Transfer On Turbulence Generating Ribs Using Dynamic Mode Decomposition, Michael Elmore Jan 2018

Analysis Of Heat Transfer On Turbulence Generating Ribs Using Dynamic Mode Decomposition, Michael Elmore

Electronic Theses and Dissertations

Ducts with turbulence-promoting ribs are common in heat transfer applications. This study uses a recent modal extraction technique called Dynamic Mode Decomposition (DMD) to determine mode shapes of the spatially and temporally complex flowfield inside a ribbed duct. One subject missing from current literature is a method of directly linking a mode to a certain engineering quantity of interest. Presented is a generalized methodology for producing such a link utilizing the data from the DMD analysis. Theory suggests exciting the modes which are identified may cause the flow to change in such a way to promote the quantity of interest, …

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A Framework For Prioritizing Opportunities Of Improvement In The Context Of Business Excellence Model In Healthcare Organization, Alia Aldarmaki Jan 2018

A Framework For Prioritizing Opportunities Of Improvement In The Context Of Business Excellence Model In Healthcare Organization, Alia Aldarmaki

Electronic Theses and Dissertations

In today's world, the healthcare sector is facing challenges to improve the efficiency and effectiveness of its operations. More and more improvement projects are being adopted to enhance healthcare services, making it more patient-centric, and enabling better cost control. Healthcare organizations strive to identify and carry out such improvement initiatives to sustain their businesses and gain competitive advantage. Seeking to reach a higher operational level of excellence, healthcare organizations utilize business excellence criteria to conduct assessment and identify organizational strengths and weaknesses. However, while such assessments routinely identify numerous areas for potential improvement, it is not feasible to conduct all …

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Influence Of Transverse Slot Jet On Premixed Flame Acceleration, Dylan Tarrant Jan 2018

Influence Of Transverse Slot Jet On Premixed Flame Acceleration, Dylan Tarrant

Electronic Theses and Dissertations

This work aims to identify the key flow parameters that influence flame acceleration in a semi-confined square channel. A transverse fluidic jet was used as an active flow blockage mechanism and to introduce turbulence into the propagating flame. Three experimental parameters were used to examine the relative influence of (1) mixture reactivity defined here as system equivalence ratio (SER), (2) jet mixture composition (JMC), and the momentum ratio (MR) on the acceleration of laminar premixed methane flame. High-speed PIV and schlieren photography were utilized to characterize the instantaneous flow-field conditions throughout the flame-jet interaction. Using these diagnostic techniques, flame front …

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Investigation Of A Self-Powered Fontan Concept Using A Multiscale Computational Fluid-Structure Interaction Model, Kyle Beggs Jan 2018

Investigation Of A Self-Powered Fontan Concept Using A Multiscale Computational Fluid-Structure Interaction Model, Kyle Beggs

Electronic Theses and Dissertations

Congenital Heart Disease (CHD) occurs in about 1\% (40,000) of newborn babies each year in the United States alone. About 10.9\% (960) of whom suffer from Hypoplastic Left Heart Syndrome (HLHS) - a subset of CHD where children are born with a single-ventricle (SV). A series of three surgeries are carried out to correct HLHS culminating in the Fontan procedure where venous flow returns passively to the lungs. The current configuration for the Fontan results in elevated Central Venous Pressure (CVP), inadequate ventricular preload, and elevated Pulmonary Vascular Resistance (PVR) leading to a barrage of disease. To alleviate these complications, …

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Monolithically Integrated Wavelength Tunable Laser Diode For Integrated Optic Surface Plasmon Resonance Sensing, Thamer Tabbakh Jan 2018

Monolithically Integrated Wavelength Tunable Laser Diode For Integrated Optic Surface Plasmon Resonance Sensing, Thamer Tabbakh

Electronic Theses and Dissertations

In this work, we demonstrate an InGaAsP multiple quantum well tunable laser diode that amalgamates two gain sections with different bandgap energies. This is achieved using selective area intermixing of the multiple quantum wells, and impurity-free vacancy induced disordering. When different current combination is injected into each section, that leads to a laser wavelength peak whose position depends on the relative magnitudes of the two injected currents. The laser wavelength can be fine-tuned from 1538 nm to 1578 nm with relatively constant output power. The free spectral range FSR of the tunable laser found to be 0.25 nm. This tunable …

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Fusing Freight Analysis Framework And Transearch Data: An Econometric Data Fusion Approach, Salah Uddin Momtaz Jan 2018

Fusing Freight Analysis Framework And Transearch Data: An Econometric Data Fusion Approach, Salah Uddin Momtaz

Electronic Theses and Dissertations

A major hurdle in freight demand modeling has always been the lack of adequate data on freight movements for different industry sectors for planning applications. Freight Analysis Framework (FAF), and Transearch (TS) databases contain annualized commodity flow data. The primary motivation for our study is the development of a fused database from FAF and TS to realize transportation network flows at a fine spatial resolution (county-level) while accommodating for production and consumption behavioral trends (provided by TS). Towards this end, we formulate and estimate a joint econometric model framework grounded in maximum likelihood approach to estimate county-level commodity flows. The …

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Electrospray And Superlens Effect Of Microdroplets For Laser-Assisted Nanomanufacturing, Eduardo Castillo Orozco Jan 2018

Electrospray And Superlens Effect Of Microdroplets For Laser-Assisted Nanomanufacturing, Eduardo Castillo Orozco

Electronic Theses and Dissertations

Nanoparticles of various materials are known to exhibit excellent mechanical, chemical, electrical, and optical properties. However, it is difficult to deposit and transform nanoparticles into large two-dimensional and three-dimensional structures, such as thin films and discrete arrays. Electrospray technology and laser heating enable the deposition of these nanoparticles through the dual role of microdroplets as nanoparticle carriers and superlenses. The main goals of this dissertation are to delineate the electrospray modes, to achieve subwavelength focusing, and to enable a process for the deposition of nanoparticles into microlayers and discrete nanodots (a nanodot is a cluster of nanoparticles) on rigid and …

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Use Of Accelerated Calcite Precipitation Method To Investigate Calcium Carbonate Precipitation From Recycled Concrete For Drainage System Applications, Toni Curate Jan 2018

Use Of Accelerated Calcite Precipitation Method To Investigate Calcium Carbonate Precipitation From Recycled Concrete For Drainage System Applications, Toni Curate

Electronic Theses and Dissertations

Recycled concrete aggregate (RCA) is a sustainable construction material that is a viable option for use in drainage systems by replacing virgin aggregate. Replacing virgin aggregate with RCA is beneficial from both economic and environmental perspectives. However, the use of RCA as pipe backfill materials may cause a long-term performance issue such as potential clogging due to fines accumulation and calcite precipitation on filter fabric. Previous studies investigated the long-term performance of RCA regarding flow rate. Therefore, this study investigated calcite precipitation potential of RCA. The Accelerated Calcite Precipitation (ACP) procedure was devised and used to estimate "life-time" calcite precipitation …

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Detailed Understanding Of Flow, Heat Transfer, And Pressure Drop Behavior In A Square Channel With 45 Deg Ribs, Lumaya Ahmed Jan 2018

Detailed Understanding Of Flow, Heat Transfer, And Pressure Drop Behavior In A Square Channel With 45 Deg Ribs, Lumaya Ahmed

Electronic Theses and Dissertations

Internal Duct Cooling (IDC) with rib turbulators is one of the common cooling techniques applied inside the turbine airfoils. It is very important for the gas turbine industry to design and develop an optimized cooling channel that maximizes the amount of heat removed, while simultaneously minimizing the pressure drop for a target overall cooling effectiveness. Angled ribs perform superior to the transverse ribs due to additional secondary flow associated with them. However, they result in a highly non-homogenous heat transfer distribution, which is a manifestation of the complex, turbulent flow field inside the channel. It is very important to comprehend …

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Wrr Files, Mohammadhossein Alipour Jan 2018

Wrr Files, Mohammadhossein Alipour

Streamflow Prediction under Extreme Data-scarcity

No abstract provided.

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Sinkhole Detection And Quantification Using Lidar Data, Amirarsalan Rajabi Jan 2018

Sinkhole Detection And Quantification Using Lidar Data, Amirarsalan Rajabi

Electronic Theses and Dissertations

The state of Florida is highly prone to sinkhole incident and formation, mainly because of the soluble carbonate bedrock which is susceptible to dissolution and groundwater recharge that causes internal soil erosions. Numerous sinkholes, particularly in Central Florida, have occurred. Florida Subsidence Incident Report (FSIR) database contains verified sinkholes with Global Positioning System (GPS) information. In addition to existing detection methods such as subsurface exploration and geophysical methods, a remote sensing method can be an alternative and efficient means to detect and characterize sinkholes with a wide coverage. the first part of this study is aimed at developing a method …

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Brain Stethoscope: A Non-Invasive Method For Monitoring Intracranial Pressure, Md Khurshidul Azad Jan 2018

Brain Stethoscope: A Non-Invasive Method For Monitoring Intracranial Pressure, Md Khurshidul Azad

Electronic Theses and Dissertations

Monitoring intracranial pressure (ICP) is important for patients with increased intracranial pressure. Invasive methods of ICP monitoring include lumbar puncture manometry, which requires high precision, is costly, and can lead to complications. Non-invasive monitoring of ICP using tympanic membrane pulse (TMp) measurement can provide an alternative monitoring method that avoids such complications. In the current study, a piezo based sensor was designed, constructed and used to acquire TMp signals. The results showed that tympanic membrane waveform changed in morphology and amplitude with increased ICP, which was induced by changing subject position using a tilt table. In addition, the results suggest …

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Masquerading Techniques In Ieee 802.11 Wireless Local Area Networks, Omar Nakhila Jan 2018

Masquerading Techniques In Ieee 802.11 Wireless Local Area Networks, Omar Nakhila

Electronic Theses and Dissertations

The airborne nature of wireless transmission offers a potential target for attackers to compromise IEEE 802.11 Wireless Local Area Network (WLAN). In this dissertation, we explore the current WLAN security threats and their corresponding defense solutions. In our study, we divide WLAN vulnerabilities into two aspects, client, and administrator. The client-side vulnerability investigation is based on examining the Evil Twin Attack (ETA) while our administrator side research targets Wi-Fi Protected Access II (WPA2). Three novel techniques have been presented to detect ETA. The detection methods are based on (1) creating a secure connection to a remote server to detect the …

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Mechanism Design Of A Compact 4-Dof Robotic Needle Guide For Mri-Guided Prostate Intervention, Shihao Zhang Jan 2018

Mechanism Design Of A Compact 4-Dof Robotic Needle Guide For Mri-Guided Prostate Intervention, Shihao Zhang

Electronic Theses and Dissertations

In the past several MRI compatible robotic needle guide devices for targeted prostate biopsy have been developed. The large and complex structure have been identified as the major limitations of those devices. Such limitations, in addition to complex steps for device to image registration have prevented widespread implementation of MRI-guided prostate biopsy despite the advantages of MRI compared to TRUS. We have designed a compact MRI-guided robotic intervention with the capability to have angulated insertion to avoid damage to any anatomical feature along the needle path. The system consists of a novel mechanism driven Robotic Needle Guide (RNG). The RNG …

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Semiconductor Design And Manufacturing Interplay To Achieve Higher Yields At Reduced Costs Using Smart Techniques, Ankush Bharati Oberai Jan 2018

Semiconductor Design And Manufacturing Interplay To Achieve Higher Yields At Reduced Costs Using Smart Techniques, Ankush Bharati Oberai

Electronic Theses and Dissertations

Since the outset of IC Semiconductor market there has been a gap between its design and manufacturing communities. This gap continued to grow as the device geometries started to shrink and the manufacturing processes and tools got more complex. This gap lowered the manufacturing yield, leading to higher cost of ICs and delay in their time to market. It also impacted performance of the ICs, impacting the overall functionality of the systems they were integrated in. However, in the recent years there have been major efforts to bridge the gap between design and manufacturing using software solutions by providing closer …

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Cavity-Coupled Plasmonic Systems For Enhanced Light-Matter Interactions, Abraham Vazquez-Guardado Jan 2018

Cavity-Coupled Plasmonic Systems For Enhanced Light-Matter Interactions, Abraham Vazquez-Guardado

Electronic Theses and Dissertations

Light-matter interaction is a pivotal effect that involves the synergetic interplay of electromag- netic fields with fundamental particles. In this regard localized surface plasmons (LSP) arise from coherent interaction of the electromagnetic field with the collective oscillation of free electrons in confined sub-wavelength environments. Their most attractive properties are strong field en- hancements at the near field, highly inhomogeneous, peculiar temporal and spatial distributions and unique polarization properties. LSP systems also offer a unique playground for fundamental electromagnetic physics where micro-scale systemic properties can be studied in the macro-scale. These important properties and opportunities are brought up in this work …

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A Framework For Miniaturized Mechanical Characterization Of Tensile, Creep, And Fatigue Properties Of Slm Alloys, Jonathan Torres-Caceres Jan 2018

A Framework For Miniaturized Mechanical Characterization Of Tensile, Creep, And Fatigue Properties Of Slm Alloys, Jonathan Torres-Caceres

Electronic Theses and Dissertations

With the heightened design complexity that may be achieved through additive manufacturing (AM) comes an equally complex set of distinct material characteristics. To properly characterize new materials for use in selective laser melting (SLM), extensive analysis is necessary. Traditional testing techniques, however, can be prohibitive in time and cost incurred. The small punch test (SPT) has been developed for such purposes, where material is scarce or costly. Although lacking standardization, SPT has been successfully employed with various materials to assess material properties such as the yield and ultimate strength and verified by traditional testing results. With the accompaniment of numerical …

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Multi-Scale Fluid-Structure Interaction Model Analysis Of Patient-Specific Geometry For Optimization Of Lvad Outflow Graft Implantation: An Investigation Aimed At Reducing Stroke Risk, Ray Prather Jan 2018

Multi-Scale Fluid-Structure Interaction Model Analysis Of Patient-Specific Geometry For Optimization Of Lvad Outflow Graft Implantation: An Investigation Aimed At Reducing Stroke Risk, Ray Prather

Electronic Theses and Dissertations

A Left Ventricular Assist Device (LVAD), is a mechanical pump capable of providing circulatory myocardium relief when used as bridge-to-transplantation by reducing the workload of a failing heart, with the additional bonus of allowing for cardiac recovery when used as destination therapy. The newer generations of continuous flow VADs are essentially axial or radial flow pumps, and while these devices are capable their efficiency depends upon fluid composition and flow field patterns. The most devastating complication of VAD therapy is caused by embolization of thrombi formed within the LVAD or inside the heart into the brain leading to stroke. Anticoagulation …

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Exploring Fpga Implementation For Binarized Neural Network Inference, Li Yang Jan 2018

Exploring Fpga Implementation For Binarized Neural Network Inference, Li Yang

Electronic Theses and Dissertations

Deep convolutional neural network has taken an important role in machine learning algorithm. It is widely used in different areas such as computer vision, robotics, and biology. However, the models of deep neural networks become larger and more computation complexity which is a big obstacle for such huge model to implement on embedded systems. Recent works have shown the binarized neural networks (BNN), utilizing binarized (i.e. +1 and -1) convolution kernel and binarized activation function, can significantly reduce the parameter size and computation cost, which makes it hardware-friendly for Field-Programmable Gate Arrays (FPGAs) implementation with efficient energy cost. This thesis …

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Numerical Study Of Interfacial Flow Using Algebraic Coupled Level Set-Volume Of Fluid (A-Clsvof) Method, Majid Haghshenas Jan 2018

Numerical Study Of Interfacial Flow Using Algebraic Coupled Level Set-Volume Of Fluid (A-Clsvof) Method, Majid Haghshenas

Electronic Theses and Dissertations

Solving interfacial flows numerically has been a challenge due to the lack of sharpness and the presence of spurious currents at the interface. Two methods, Algebraic Coupled Level Set-Volume of Fluid (A-CLSVOF) method and Ghost Fluid Method (GFM) have been developed in the finite volume framework and employed in several interfacial flows such as Rayleigh-Taylor instability, rising bubble, impinging droplet and cross-flow oil plume. In the static droplet simulation, A-CLSVOF substantially reduces the spurious currents. The capillary wave relaxation shows that this method delivers results comparable to those of more rigorous methods such as Front Tracking methods for fine grids. …

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Dynamic Hotspot Identification For Limited Access Facilities Using Temporal Traffic Data, Samer Al Amili Jan 2018

Dynamic Hotspot Identification For Limited Access Facilities Using Temporal Traffic Data, Samer Al Amili

Electronic Theses and Dissertations

Crash frequency analysis is the most critical tool to investigate traffic safety problems. Therefore, an accurate crash analysis must be conducted. Since traffic continually fluctuates over time and this effects potential of crash occurrence, shorter time periods and less aggregated traffic factors (shorter intervals than AADT) need to be used. In this dissertation, several methodologies have been conducted to elevate the accuracy of crash prediction. The performance of using less aggregated traffic data in modeling crash frequency was explored for weekdays and weekends. Four-time periods for weekdays and two time periods for weekends, with four intervals (5, 15, 30, and …

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Hole Selective Tunneling Oxide Applications With Insight Into Sophisticated Characterization Techniques, Nizamettin Kortan Ogutman Jan 2018

Hole Selective Tunneling Oxide Applications With Insight Into Sophisticated Characterization Techniques, Nizamettin Kortan Ogutman

Electronic Theses and Dissertations

Tunneling metal oxide layers combined with industrially applicable novel cleaning methods can boost the current efficiency limit, which corresponds to approximately %22 in production, of crystalline silicon (c-Si) solar cells. Within the scope of this dissertation, extremely thin tunneling layers (1-3nm) of aluminum oxide is studied in conjunction with the development of wet cleaning procedures that are feasible in production lines currently exist today. These tunneling stacks are deployed to serve as exceptional surface passivation layers due to the inherent built-in charge provided by aluminum oxide. This capability is further strengthened by the introduction of extremely well controlled wet chemical …

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A Multisystem Approach For The Characterization Of Bacteria For Sustainable Agriculture, Briana Lee Jan 2018

A Multisystem Approach For The Characterization Of Bacteria For Sustainable Agriculture, Briana Lee

Electronic Theses and Dissertations

The chemical, physical, and biological properties of bacteria developing resistance have been explored in animal based bacteria while plant bacteria have been largely neglected. Thus, the ability to probe changes in stiffness, adhesion, binding interactions and molecular traits of bacteria causing plant diseases is of great interest to develop a new generation of more potent, yet sustainable, pesticides. Our study aims to investigate the physical and chemical properties of bacterial systems, in particular their cell walls. Building upon this fundamental understanding of the cells, we also investigate the physicochemical responses associated to multivalent nanoparticle-based bactericide treatments on bacterial systems identified …

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Categorical Range Reporting In 2d Using Wavelet Tree, Swathi Kanthareddy Sumithra Jan 2018

Categorical Range Reporting In 2d Using Wavelet Tree, Swathi Kanthareddy Sumithra

Electronic Theses and Dissertations

The research involved optimizing the space and bounding the output time by the output size in categorical range reporting of points within the given rectangle query Q in two dimension using wavelet trees and range counting. The time taken to report those points and space to tore n points in set S can be done using wavelet tree and range counting. Consider set S consisting of n points in two-dimension. An orthogonal range reporting query rectangle Q = [a,b] x [c,d] on set S is sent to report the set of points in S which interacts with the query rectangle[Q]. …

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Characterization Of Acoustic Modes In Aeroengines, Michelle Otero Jan 2018

Characterization Of Acoustic Modes In Aeroengines, Michelle Otero

Electronic Theses and Dissertations

Acoustic instabilities remain a key design concern faced in the development of liquid rocket engines. The interaction between the acoustic modes and the occurring combustion reactions can be detrimental to the engine. The fluctuating pressure waves resulting from the flame oscillations in the system can potentially lead to engine failure. For this reason, research in acoustic instabilities and methods to minimize the influences on the engine, has maintain interest in the aerospace community. The scope of this study was to design, optimize and characterize acoustic behaviors of a scaled rocket combustion chamber simulating acoustic pressure waves. Tangential and longitudinal acoustic …

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Econometric Modeling Analysis Of Public Transit Ridership: Application For Orlando Region, Moshiur Rahman Jan 2018

Econometric Modeling Analysis Of Public Transit Ridership: Application For Orlando Region, Moshiur Rahman

Electronic Theses and Dissertations

Policy makers are considering several alternatives to counter the negative externalities of personal vehicle dependence. Towards this end, public transit investments are critical in growing urban regions such as Orlando, Florida. Transit system managers and planners mostly rely on statistical models to identify the factors that affect ridership as well as quantifying the magnitude of the impact on the society. These models provide vital feedback to agencies on the benefits of public transit investments which in turn act as lessons to improve the investment process. We contribute to public transit literature by addressing several methodological challenges for transit ridership modeling. …

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