Feasibility Study and Model Development for Implementation of in Situ Raman Spectroscopy for YBCO Thin Film Growth PDF Download

Author: John David Busbee
Publisher:
ISBN:
Category : High temperature superconductors
Languages : en
Pages : 140

View

Book Description

Author: Stefan Muthmann
Publisher:
ISBN: 9783893367740
Category :
Languages : en
Pages : 134

View

Book Description

Author: Jing Gui
Publisher:
ISBN:
Category :
Languages : en
Pages : 528

View

Book Description

Author: Jaypee Quiño
Publisher:
ISBN: 9783945806111
Category :
Languages : en
Pages :

View

Book Description

Author: Khaled Khalili
Publisher:
ISBN:
Category : Chemical detectors
Languages : en
Pages : 88

View

Book Description
In the upgrading of heavy feeds, it is essential to avoid the onset formation of mesophase, which is considered a precursor for coke formation. The formation of this aromatic dense phase leads to serious problems such as catalyst deactivation, limiting the vacuum residue conversion, and fouling in the reactors and the downstream equipment; subsequently, a costly mechanical removal will be necessary to remove the coke. Therefore, tracking of the mesophase formation at in-situ conditions is important step towards avoiding the onset formation of carbonaceous mesophase. In this work, a fiber-coupled in-situ Raman hot reactor was designed, constructed and validated. The system has been developed as on-line chemical sensor to track evolution of the two graphitization Raman bands associated with the mesophase formation, namely the 1575cm-1 band and the band located near 1340cm-1. The operation of the system is based on acquiring real-time backscattered Raman spectra from a hot stage reactor running at high temperature and sometimes high-pressure conditions. The outcome of this system has been validated using non-reactive and reactive systems. In terms of non-reactive systems, the spectra of some common solvents such as toluene and 1-methylnapthalene have been acquired using this system and then compared with the published spectra; excellent spectral matching in the range of ± 5cm-1 is observed. On the other hand, the hydro-desulfurization reaction of benzothiophene using 1-methylnapthalene as a solvent has been used as a model reaction for system validation. This reaction has been conducted ex-situ and in-situ at the same experimental conditions i.e. 290° C and 2.5 MPa of hydrogen pressure. The GC/MS analysis of the ex-situ shows hydrodesulphurization of benzothiophene and formation of ethylbenzene, which is in agreement with the well-known chemistry of this reaction; in addition, a considerable hydrogenation of the solvent was observed in the products of the ex-situ runs, which confirms the hydrogenation capability of the used catalyst. The spectral data, which have been acquired during the in-situ runs, have been preprocessed using the airPLS algorithm to remove the fluorescence background from the spectra that have been then analyzed using multivariate PCA analysis. The PCA analysis confirms the evolution of the Raman bands associated with ethylbenze formation and the decline of the Raman bands attributed to benzothiophen; moreover, the PCA analysis also shows a concomitant decrease of the aromatic content of the mixture via hydrogenation of aromatic rings which confirms the hydrogenation of the solvent that have been observed in the ex-situ runs.

Author: Juan Carlos González González
Publisher:
ISBN:
Category :
Languages : en
Pages : 370

View

Book Description

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description

Author: Andrew Li-Pook-Than
Publisher:
ISBN:
Category : University of Ottawa theses
Languages : en
Pages : 190

View

Book Description

Author: Glenn Washer
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 0

View

Book Description
The proposed research will develop the application of Raman Spectroscopy as a nondestructive evaluation tool for the condition assessment of carbon fiber composites. Composite materials are increasingly being used in engineered structures and components, ranging from highway bridges to airframes and pressure vessels. These materials have a high strength to mass ratio, making them idealmaterials for inclusion in space vehicles, hydrogen cars and aircraft. There exists a critical need to develop nondestructive evaluation technologies that can be used to assess the condition of these materials in-situ, such that components and systems can be managed anrepaired during their service lives. To date, NDE technologies developed for the inspection of composite materials have focused on mechanical damage scenarios, such as impact and fatigue. There is growing concern that environmental degradation of these materials leads to reduced strength during their service lives, and presently there are no NDE technologies capable of characterizing the degradation of composite materials in-situ. The proposed research will investigate if Raman spectroscopy can be used for the condition assessment of composite materials during their service lives. Raman spectroscopy is a laser technique that is sensitive to molecular interactions in ordered materials such as graphite and carbon fibers. For carbon materials, the technique has been shown tobe sensitive to applied elastic stresses and structural order on a molecular level. Traditionally a laboratory technique, new instrumentation implementing fiber-optic probes has extended the potential for this technology beyond the laboratory. The potential exist for implementation as a hand-held device for the inspection of engineering components and structures, including bridges and hydrogen vehicles.

Author: Javier A. Falcon
Publisher:
ISBN:
Category : Biomolecules
Languages : en
Pages : 336

View

Book Description