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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 50 for “"Laser absorption"”.
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Hydrogen purity assessment using laser absorption Spectroscopy
… (𝐻2-Spectrometer) based on direct Tunable Diode Laser Absorption Spectroscopy (d-TDLAS). The goal is to establish a traceable and accurate methodology for hydrogen purity and concentration measurement without relying on calibration gases. The main objective of this research is to develop and …
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Exhaled breath analysis using laser absorption spectroscopy
… and therapeutic monitoring. For this thesis, laser spectroscopic techniques were employed to measure exhaled nitric oxide (NO), carbonyl sulfide (OCS) and carbon dioxide (CO2). A pulsed quantum cascade laser operating at 4.86 microns was coupled to a 36-m optical path length Herriott cell for …
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Novel diode laser absorption techniques for combustion diagnostics
… such as gas chromatography. In this thesis two laser absorption measurement techniques are applied to measure the soot distribution, and acetylene concentration profiles in a flat-flame burner. The in-situ measurement of the distribution of particulate matter in flames is a key step in …
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Laser absorption spectroscopy for investigation of hypersonic propulsion
… gas in the ACT-II facility, using tunable diode laser absorption spectroscopy (TDLAS) to measure temperature and nitric oxide (NO) concentration. Another fundamental challenge associated with scramjet operation is achieving efficient fuel-air mixing and ignition within the short residence times …
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Kinetics and dynamics measured using IntraCavity Laser Absorption Spectroscopy
IntraCavity Laser Absorption Spectroscopy (ICLAS) is a high-resolution, high sensitivity spectroscopic method capable of measuring line positions, linewidths, lineshapes, and absolute line intensities with a sensitivity that far exceeds that of a traditional multiple pass absorption cell or Fourier …
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Shock Tube and Mid-IR Laser Absorption Study of Combustion Kinetics
… fuels. Specifically, a shock tube and direct laser absorption systems are used to investigate the ignition and pyrolysis processes of target fuels. The research problem is motivated by concern about climate change and diminishing fossil fuels. There is a need to develop advanced combustion …
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Near-infrared tunable diode laser absorption spectrometer for trace gas detection
A ground based near-infrared tunable diode laser absorption spectrometer (TDLAS), capable of measuring methane (CH₄) and nitrous oxide (N₂0) in their natural abundance's within the atmosphere, has been designed and constructed. The spectrometer has high resolution (0.0003 cm⁻¹), high precision …
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Developments in Raman spectrometry and intracavity laser absorption spectrometry for quantitative analysis
… and transmission Raman spectrometry) at a laser wavelength of 785 nm were then used to non-destructively analyse 380 Chlortrimeton tablets. With external calibration tablets, predictions of the API mass based on reflectance Raman spectra were in good agreement with the stated mass. However, …
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Determination of Flame Dynamics for Unsteady Combustion Systems using Tunable Diode Laser Absorption Spectroscopy
… in chemical reaction rate. Tunable Diode Laser Absorption Spectroscopy (TDLAS), centered over two water absorption features, allows a dynamic measurement of the product gas temperature. The response in product gas temperature directly relates to the enthalpy fluctuations that couple to the …
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Extending frequency modulation spectroscopy : sensitive and selective high resolution laser absorption in the visible and ultraviolet
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1996.
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Determining Emission Factors from Marine Vessels Employing Differential Optical Absorption Spectroscopy (DOAS) and Tunable Diode Laser Absorption Spectroscopy (TDLAS)
High SO2 concentrations are harmful to human health and impact climate by affecting cloud formation. Ship contrails are the major source of SO2 in the open-ocean and impact coastal region air quality. The International Maritime Organization (IMO) regulates SO2 emissions by requiring ships to use …
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The study of bimolecular radical reactions using a novel time-resolved photoionization time-of-flight mass spectrometry and laser absorption spectrometry apparatus
… of these systems. The apparatus uses laser absorption spectrometry to probe a radical of interest and thus measure its transient concentration quasi-continuously to precisely determine the kinetics of the reaction. At the same time, the apparatus samples the reactive mixture at various …
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Time-resolved absorption spectroscopy of the rare gas dimer Rydberg states
… both through intra-cavity and multi-pass laser absorption spectroscopy.
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Two Innovative Applications Combining Fiber Optics and High Power Pulsed Laser: Active Ultrasonic Based Structural Health Monitoring and Guided Laser Micromachining
… optics techniques involving high power pulse laser delivery. The first research topic is "Embedded Active Fiber Optic Sensing Network for Structural Health Monitoring in Harsh Environments", which uses the fiber delivered pulse laser for acoustic generation. The second research topic is "Fiber …
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High current coaxial ion beam/laser beam spectrometer
… In the new ion beam machine, the ion beam and laser beam overlap in a coaxial geometry. The machine has much higher ion current than an apparatus previous used. The laser beam induces transitions between internal states of the molecular ion. The transitions are detected by allowing the ion beam …
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Novel absorption detection techniques for capillary electrophoresis
… a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the [mu]M level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary …
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