Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 86 for “"Gas Sensors"”.
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Development of Graphene Based Gas Sensors
… sheet of high quality graphene was essential for gas sensing applications. In this study, Chemical Vapor Deposition (CVD) was used to grow large scale graphene on copper foil. Graphene deposition was carried out on a copper foil and transferred to different substrates by wet etching of Cu foil by …
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Device structures for microelectronic gas sensors.
Massachusetts Institute of Technology. Dept. of Electrical Engineering. Thesis. 1974. Elec.E.
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Design and development of electrochemical gas sensors
Historically, electrochemical gas sensors had suffered from several drawbacks such as poor temperature coefficient, leakage, susceptibility to shock and vibration and orientation sensitivity, which led to poor field reliability. In the present work these problems have largely been overcome by …
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Inkjet Printed Graphene-Based Smart Gas Sensors
The current commercial landscape for gas sensing is dominated by metal oxide (MOx) based sensors due to their balance of performance and cost as well as the opportunity for simple device integration, potential for miniaturisation and incorporation into multi-analyte detection systems. However, MOx …
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Modeling and Sensitivity Analysis for Trace Gas Sensors
Trace gas sensors can detect very low concentrations of gases such as methane and sulfur dioxide. An important class of trace gas sensors are quartz-enhanced photoacoustic spectroscopy (QEPAS) sensors, which employ a quartz tuning fork (QTF) and modulated laser to detect trace gases. Existing …
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Carbon nanotube based carbon dioxide gas sensors for respiratory monitoring.
… for monitoring the concentration of exhaled CO2 gas in human breath. Limitations such as high power, large size, lack of portability and undesirable use of sampling tubes are experienced currently during respiratory CO2 monitoring. CO2 being a very important biomarker, it is desirable to extend …
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STUDIES OF TIN OXIDE GAS SENSORS FOR GAS CHROMATOGRAPHIC DETECTION
Gas sensitive semiconductors have been known for many years and applied in static gas alarm systems for the monitoring of hazardous gases, however, their application has been limited by a lack of selectivity. In this work a semiconducting gas sensor has been configured for use as a gas …
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Cryptophane Derivatives as Gas Sensors and Hyperpolarized Xenon-129 Biosensors
ABSTRACT CRYPTOPHANE DERIVATIVES AS GAS SENSORS AND HYPERPOLARIZED XENON-129 BIOSENSORS Najat S. Khan Professor Ivan J. Dmochowski This thesis describes the progress in the development of cryptophanes for three different applications: encapsulation of noble gases, 129Xe NMR biosensing for cancer …
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Development of low-cost in situ gas sensors for oceanographic applications
… compact, low-power, and accurate in situ sensors would significantly enhance the spatiotemporal resolution of oceanographic data and enable widespread monitoring of dissolved gases throughout the ocean. This, in turn, would deepen our understanding of how, where, and when changes are …
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Development of Low-Cost In Situ Gas Sensors for Oceanographic Applications
… compact, low-power, and accurate in situ sensors would significantly enhance the spatiotemporal resolution of oceanographic data and enable widespread monitoring of dissolved gases throughout the ocean. This, in turn, would deepen our understanding of how, where, and when changes are …
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Toxic gas sensors using thin film transistor platform at low temperature
… as SnO₂, TiO₂, ZnO and WO₃ are commonly used for gas sensing in the form of thin film resistors (TFRs) given their high sensitivity to many vapor species, simple construction and capability for miniaturization. Furthermore, they are generally more stable than polymer-based gas sensors. However, …
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Optical gas sensors based on correlation spectroscopy using a Fabry-Perot interferometer
In this work we present an analysis of gas sensors based on correlation spectroscopy with a Fabry-Perot interferometer (FPI). In this technique the spectral FPI transmission fringe pattern is matched with ro-vibrational absorption lines. To produce the cross correlation principle the FPI fringe …
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Effects of Downwash when Measuring Gas Concentration with UAV-Mounted Gas Sensors
… to cause significant changes in density-based gas concentration measurements. US regulations evaluate gas concentration as a function of gas density, and accurate concentration measurements are critical for protecting health and safety, which means evaluation of actual downwash effects on …
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Synthesis, Fabrication and Surface Modification of Nanocrystalline Nickel Oxide for Electronic Gas Sensors
Recently, metal oxide gas sensors have attracted much attention in connection with monitoring of combustible and toxic gases because of their higher sensitivity, fast response and recovery times, low power consumption, and low fabrication cost. Nickel oxide (NiO) is a wide band gap and p-type …
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Highly Sensitive and Selective Gas Sensors Based on Vertically Aligned Metal Oxide Nanowire Arrays
… arrays were used as the active materials for gas detection. Metal oxide nanowire arrays share similar 3D structures as the array of mammal's olfactory receptors and the chemical reactivity of nanowire array can be modified by surface coatings. In this dissertation, two standalone gas sensors …
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Comparative study of rare- earth based ferrites for flammable and volatile organic compound gas sensors
… Another commonly used highly flammable gas is liquefied petroleum gas (LPG), commonly known as a cooking gas, which is widely available in almost all communities and working environments to create fires for various uses. This gas causes many fatalities due to its nature of complexities …
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INVESTIGATIONS OF OXIDE AND SULFIDE BASED LOW DIMENSIONAL NANO STRUCTURES FOR CONDUCTOMETRIC GAS SENSORS, MEMRISTORS AND PHOTODETECTORS
… that can have potential applications in chemical gas sensor, optoelectronic devices and memristor. How ever, in some cases it is envisioned that appropriate doping as well as phase stabilization is important in enhancing their material properties. This work presents the synthesis, characterization …
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Characterizing the role of defects on the sensing performance of carbon nanotube and graphene based gas sensors
… on the sensing mechanisms and performance of gas sensors made from films of carbon nanotubes, chemical vapor deposition (CVD) graphene film, CVD graphene ribbons, and surfactant exfoliated graphene. The definition of defects on carbon materials is the disordered carbon atoms formed due to …
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Electrospun nanofibers : opportunities in environment and energy
… monitoring by improving solar cells and gas sensors. However difficulties in large scale manufacturing of these nanostructures have prevented most of these devices from entering the marketplace. Electrospinning is a simple, versatile and scalable technique to fabricate one-dimensional …
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