Profiling of Redox Atmosphere in Flames by Chemical Seeding/Planar Laser-Induced Fluorescence (CS/PLIF)

2005 ◽  
Vol 128 (4) ◽  
pp. 765-772 ◽  
Author(s):  
K. Kitagawa ◽  
S. Itoh ◽  
N. Arai ◽  
Ashwani K. Gupta
Keyword(s):  
Rotational Temperature ◽  
Thermal Dissociation ◽  
Flame Temperature ◽  
Ccd Camera ◽  
Laser Induced Fluorescence ◽  
Charge Coupled Device ◽  
Planar Laser ◽  
A Charge ◽  
Local Value ◽  
Redox Index

Knowledge on the local value of reducing and oxidizing (redox) atmospheres in flames is among the most important issues to be desired by combustion engineers. In this study, the spatial distribution of a redox atmosphere in flames has been measured experimentally by the chemical seeding/laser-induced fluorescence (CS/LIF) technique. A solution of iron was sprayed into a premixed propane-air flame supported on a slot burner. The LIF intensity of FeO band was compared to that of a Fe line to estimate the experimentally determined degree of atomization in the reaction FeO→Fe+O. The flame temperature profile was determined as a rotational temperature and was obtained by comparing the LIF (laser-induced fluorescence) intensities of OH rotational lines. The degree of atomization was theoretically calculated on the basis that simple thermal dissociation takes place in the reaction. The redox atmosphere, or a redox index, is defined as the ratio of the experimentally determined to theoretically calculated degrees of atomization. Two-dimensional distributions or profiles of the excitation temperature, experimentally determined degree of atomization, and redox index have been measured using a charge coupled device (CCD) camera fitted with an optical bandpass filter and the associated signal processing using a computer. This method has been successfully applied to quantitatively illustrate the local atmosphere and profile of the redox atmosphere in flames.

scholarly journals Spectroscopic flat-fields can be used for precision CCD gain and noise tests

2021 ◽  
Vol 38 ◽  
Author(s):  
J. Gordon Robertson
Keyword(s):  
Ccd Camera ◽  
Matched Pair ◽  
Optical Fibres ◽  
Charge Coupled Device ◽  
Small Areas ◽  
Flat Field ◽  
Basic Parameters ◽  
The Mean ◽  
A Charge ◽  
Analogue To Digital

Abstract One of the basic parameters of a charge coupled device (CCD) camera is its gain, that is, the number of detected electrons per output Analogue to Digital Unit (ADU). This is normally determined by finding the statistical variances from a series of flat-field exposures with nearly constant levels over substantial areas, and making use of the fact that photon (Poisson) noise has variance equal to the mean. However, when a CCD has been installed in a spectroscopic instrument fed by numerous optical fibres, or with an echelle format, it is no longer possible to obtain illumination that is constant over large areas. Instead of making do with selected small areas, it is shown here that the wide variation of signal level in a spectroscopic ‘flat-field’ can be used to obtain accurate values of the CCD gain, needing only a matched pair of exposures (that differ in their realisation of the noise). Once the gain is known, the CCD readout noise (in electrons) is easily found from a pair of bias frames. Spatial stability of the image in the two flat-fields is important, although correction of minor shifts is shown to be possible, at the expense of further analysis.

Combinatorial Study of Zeolites in Catalyzing the Acylation of Benzene via Laser-Induced Fluorescence Imaging

2002 ◽  
Vol 56 (8) ◽  
pp. 1044-1047 ◽  
Author(s):  
Hui Su ◽  
Edward S. Yeung
Keyword(s):  
Fluorescence Imaging ◽  
High Throughput Screening ◽  
Ccd Camera ◽  
Laser Induced Fluorescence ◽  
Solid Catalyst ◽  
Mfi Zeolite ◽  
Gaseous Products ◽  
Beta Zeolites ◽  
Higher Temperature ◽  
A Charge

Laser-induced fluorescence imaging (LIFI) has been developed into a high-throughput screening (HTS) technique for heterogeneous catalysis. A laser beam is focused into a sheet parallel to the surface of the solid catalyst. Fluorescence from selected gaseous products formed immediately above the surface is imaged by a charge-coupled device (CCD) camera. Here, in situ LIFI was used to simultaneously screen the catalytic properties of a 15-member library consisting of mordenites (MOR), ferrierites (FER), ZSM-5 (MFI), zeolite γ-(gamma) (FAU), and beta zeolites (BEA) with various Si/Al ratios in the acylation of benzene with phthalic anhydride. Only beta zeolites were found to be active in this reaction over the temperature range of 190 to 340 °C. Substantial deactivation of beta zeolites was observed within less than one minute at higher temperature and the degree of deactivation varied with reaction temperature and the composition of the reactant mixture, as well as the Si/Al ratio of the beta zeolites. The deactivated beta zeolites can be regenerated partially by heating in a flow of oxygen. Up to 80% recovery of the catalytic activity was obtained. Similar recovery was observed after several deactivation–regeneration cycles.

Description And Preliminary Performance Of A Charge-Coupled Device (CCD) Camera

1981 ◽  
Author(s):  
A. Bouere ◽  
J. Cretolle ◽  
B. Fort ◽  
R. Jouan ◽  
M. Gorisse ◽  
...  
Keyword(s):  
Ccd Camera ◽  
Charge Coupled Device ◽  
A Charge

Soot temperature and concentration measurements from colour charge coupled device camera images using a three-colour method

2001 ◽  
Vol 215 (9) ◽  
pp. 1041-1052 ◽  
Author(s):  
S Simonini ◽  
S. J. Elston ◽  
C. R. Stone
Keyword(s):  
Response Curve ◽  
Flame Temperature ◽  
Ccd Camera ◽  
Soot Concentration ◽  
Charge Coupled Device ◽  
Soot Loading ◽  
Concentration Measurements ◽  
Operating Points ◽  
Late Stages ◽  
Colour Charge

The three-colour method has been developed in order to turn chromatic information in charge coupled device (CCD) camera images of combustion into flame temperature and soot concentration measurements. The method showed the following advantages over the two-colour method from which it is derived: only one camera is needed; no further calibration is required once the response curve of the camera is known; it does not rely on light intensity but on ratios between colour components, making it easy to adapt to different operating points with different name brightness. The results on temperature evaluation were compared with a thermodynamic model, and better agreement was found in the late stages of the cycle, when the radiation from chemical reactions becomes negligible. The error analysis showed that the calculations for soot concentration are ill-conditioned, but when the results are integrated to give a soot loading the accuracy is improved and there is clear evidence of soot evolution and destruction during combustion.

Research on Magnet Excitation and Image Processing Used in Visual Detection

2011 ◽  
Vol 216 ◽  
pp. 793-797
Author(s):  
Li Bing Bai ◽  
Shu Lin Tian ◽  
Yu Hua Cheng
Keyword(s):  
Image Processing ◽  
Eddy Current ◽  
Visual Detection ◽  
Polarized Light ◽  
Ccd Camera ◽  
Experimental Tests ◽  
Laser Source ◽  
Magnetic Excitation ◽  
Charge Coupled Device ◽  
A Charge

A novel visual detection set, which can detect sub-superficial defects in conductive specimens, is presented in this paper. The set has a laser source, a charge coupled device (CCD) camera, and a magnetic excitation. The linear polarized light given off by the laser source is modulated by the superimposition of the magnetic fields induced by the coil and eddy current, and acquired by the CCD. Given the exciting current is known and the eddy current is influenced by the defects, the information of defects can be extracted from the image acquired by CCD. The magnet excitation and image processing are described in detail. Experimental tests have been done and the method presented is proved by the experimental results.

Using laser speckle to measure the roughness of paper

TAPPI Journal ◽  
2011 ◽  
Vol 10 (3) ◽  
pp. 7-13
Author(s):  
ABDIEL PINO ◽  
JOSEP PLADELLORENS ◽  
JOSEP F. COLOM ◽  
ORIOL CUSOLA ◽  
AGUSTÍN TOSAS
Keyword(s):  
Image Processing ◽  
Speckle Pattern ◽  
Ccd Camera ◽  
Laser Speckle ◽  
Charge Coupled Device ◽  
Paper Surface ◽  
Surface Profiling ◽  
Base Paper ◽  
Occurrence Matrix ◽  
A Charge

Paper surface roughness is an important consideration in paper and board destined for printing. The amount of coating and method of application depend on the roughness of the base paper. We present a method to measure the roughness of the paper based on analysis of speckle pattern on the surface. Images are captured by means of a simple configuration using a laser and a charge-coupled device (CCD) camera. Then, we apply digital image processing using a co-occurrence matrix, providing for a noncontact surface profiling method that can be used online.

Single-Shot Multiwavelength Imaging of Laser Plumes

1998 ◽  
Vol 52 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Matthew P. Nelson ◽  
Wendy C. Bell ◽  
Michael L. McLester ◽  
M. L. Myrick
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Ccd Camera ◽  
Chemical Imaging ◽  
Single Shot ◽  
Charge Coupled Device ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Optic Array ◽  
A Charge

A novel optical approach to single-shot chemical imaging with high spectroscopic resolution is described with the use of a prototype dimension-reduction fiber-optic array. Images are focused onto a 30 × 20 array of hexagonally packed 250 μm o.d. f/2 optical fibers that are drawn into a 600 × 1 distal array with specific ordering. The 600 × 1 side of the array is imaged with an f/2 spectrograph equipped with a holographic grating and a charge-coupled device (CCD) camera for spectral analysis. Software is used to extract the spatial/spectral information contained in the CCD images and de-convolute them into wavelength-specific reconstructed images or position-specific spectra that span a 190 nm wavelength space. “White light” zero-order images and first-order spectroscopic images of laser plumes have been reconstructed to illustrate proof-of-principle. Index Headings: Fiber optics; Chemical imaging; Spectroscopic imaging; Charged-coupled device (CCD); Laser-induced breakdown spectroscopy (LIBS).

Imaging and Characterization of Plasma Plumes Produced During Laser Ablation of Zirconium Carbide

1992 ◽  
Vol 285 ◽  
Author(s):  
Darryl P. Butt ◽  
Paul J. Wantuck
Keyword(s):  
Zirconium Carbide ◽  
Ccd Camera ◽  
Laser Induced Fluorescence ◽  
Diagnostic Methods ◽  
Total Emission ◽  
Low Emission ◽  
Laser Diagnostic ◽  
Planar Laser ◽  
Plasma Plumes

ABSTRACTLaser diagnostic methods are developed and used to characterize the behavior of laser ablated zirconium carbide (ZrC). Emission from zirconium atoms dominates the total emission of the plasma plumes, which are estimated to have excitation temperatures of 9000 to 12,000 K under the conditions studied. Emission from species such as C, C2, and C3 were absent from the spectra due to the inherently low emission intensities of these species compared with that of Zr. Using a CCD camera, images of the plasma plumes are obtained from the emission and through the use of planar laser induced fluorescence of zirconium atoms.

Simultaneous Two-Dimensional Visualization of Soot and OH in Flames Using Laser-Induced Fluorescence

1996 ◽  
Vol 50 (9) ◽  
pp. 1182-1186 ◽  
Author(s):  
Per-Erik Bengtsson
Keyword(s):  
Laser Radiation ◽  
Detection System ◽  
Frequency Doubling ◽  
Ccd Camera ◽  
Laser Induced Fluorescence ◽  
Oh Radicals ◽  
Single Shot ◽  
Two Dimensional ◽  
Charge Coupled Device ◽  
Reaction Zones

Two-dimensional visualization of soot has been realized in flames with the use of laser-induced fluorescence in C2 from laser-vaporized soot [LIF(C2)LVS]. Soot particles are heated to vaporization temperatures by the absorption of laser radiation. C2 radicals produced by this process are excited at wavelengths around 563 nm through the transition v’ = 0 d3Πg ← v” = 1 a3Πu, and the subsequent fluorescence at ∼516 nm is detected. By frequency-doubling of the laser radiation, wavelengths around 281.5 nm are achieved, which can excite OH radicals to the v’ = 1 A2∑+ state from v” = 0 X2Π, with subsequent fluorescence at ∼310 nm. With the use of both these excitation wavelengths, and a Cassegrainian split-mirror telescope as the imaging detection system in front of the charge-coupled device (CCD) camera, simultaneous two-dimensional single-shot images of soot and OH were obtained on a single CCD chip, thus enabling both sooting regions and reaction zones in flames to be monitored.

Image Information Obtained Using a Charge-Coupled Device (CCD) Camera During an Immersion Liquid Evaporation Process for Measuring the Refractive Index of Solid Particles

2018 ◽  
Vol 72 (6) ◽  
pp. 908-912 ◽  
Author(s):  
Ilpo Niskanen ◽  
Veijo Sutinen ◽  
Göran Thungström ◽  
Jukka Räty
Keyword(s):  
Refractive Index ◽  
Physical Property ◽  
Ccd Camera ◽  
Solid Particles ◽  
Evaporation Process ◽  
Immersion Liquid ◽  
Refractive Index Measurement ◽  
Charge Coupled Device ◽  
Liquid Evaporation ◽  
A Charge

The refractive index is a fundamental physical property of a medium, which can be used for the identification and purity issues of all media. Here we describe a refractive index measurement technique to determine simultaneously the refractive index of different solid particles by monitoring the transmittance of light from a suspension using a charge-coupled device (CCD) camera. An important feature of the measurement is the liquid evaporation process for the refractive index matching of the solid particle and the immersion liquid; this was realized by using a pair of volatile and non-volatile immersion liquids. In this study, refractive indices of calcium fluoride (CaF2) and barium fluoride (BaF2) were determined using the proposed method.

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