End-point determination on-line and reaction co-ordinate modelling of homogeneous and heterogeneous reactions in principal component space using periodic near-infrared monitoring

The Analyst ◽  
1996 ◽  
Vol 121 (8) ◽  
pp. 1003 ◽  
Author(s):  
Timothy Norris ◽  
Paul K. Aldridge
Keyword(s):  
Near Infrared ◽  
Principal Component ◽  
Heterogeneous Reactions ◽  
Homogeneous And Heterogeneous Reactions ◽  
End Point ◽  
On Line ◽  
Point Determination ◽  
Infrared Monitoring

On-Line Monitoring of Melt-Extrusion Transesterification of Ethylene Vinylacetate Copolymers by near Infrared Spectroscopy and Chemometrics

2002 ◽  
Vol 10 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Tsuyoshi Furukawa ◽  
Yasuo Kita ◽  
Shigehiro Sasao ◽  
Kimihiro Matsukawa ◽  
Masahiro Watari ◽  
...  
Keyword(s):  
Near Infrared ◽  
Nir Spectroscopy ◽  
Principal Component ◽  
Intensity Change ◽  
Melt Extrusion ◽  
Peak Intensity ◽  
Fibre Optic Probe ◽  
On Line ◽  
Significant Intensity ◽  
Optic Probe

The melt-extrusion transesterification of ethylene/vinylacetate (EVA) copolymer to ethylene/vinylalcohol (EVAL) copolymers has been monitored by on-line near infrared (NIR) spectroscopy. A total of 60 NIR spectra were measured within 37 minutes after the initial addition of octanol (reagent) and catalyst (sodium methoxide) at the exit of the extruder by use of a fibre-optic probe. The most significant intensity change is observed for a band at 7089 cm−1 due to the first overtone of an OH stretching mode of the EVAL copolymers. We can monitor the progress of the reaction by plotting the peak intensity at 7089 cm−1 only. A principal component analysis (PCA) was carried out for the series of NIR spectra in the 7300–6900 cm−1 region. A score plot of PCA factor 1 is almost identical with the plot of the peak intensity at 7089 cm−1. Calibration models for predicting the vinyl acetate content in EVA copolymers have been developed by use of partial least squares (PLS) regression. The correlation coefficient and standard error of prediction are 0.96 and 0.85%, respectively, indicating that the described technique can be used to monitor the transesterification reaction.

scholarly journals On-line near infrared monitoring of glycerol-boosted anaerobic digestion processes: Evaluation of process analytical technologies

2007 ◽  
Vol 99 (2) ◽  
pp. 302-313 ◽  
Author(s):  
Jens Bo Holm-Nielsen ◽  
Carina Juel Lomborg ◽  
Piotr Oleskowicz-Popiel ◽  
Kim H. Esbensen
Keyword(s):  
Anaerobic Digestion ◽  
Near Infrared ◽  
On Line ◽  
Infrared Monitoring

A Hyperspectral Imaging System for Identification of Faecal and Ingesta Contamination on Poultry Carcasses

2003 ◽  
Vol 11 (4) ◽  
pp. 269-281 ◽  
Author(s):  
Kurt C. Lawrence ◽  
William R. Windham ◽  
Bosoon Park ◽  
R. Jeff Buhr
Keyword(s):  
Real Time ◽  
Hyperspectral Imaging ◽  
Near Infrared ◽  
Imaging System ◽  
Principal Component ◽  
Ccd Camera ◽  
Sample Population ◽  
Multivariate System ◽  
Ratio Image ◽  
On Line

A method and system for detecting faecal and ingesta contaminants on poultry carcasses were demonstrated. A visible/near infrared monochromator, which measured reflectance and principal component analysis were first used to identify key wavelengths from faecal and uncontaminated skin samples. Measurements at 434, 517, 565 and 628 nm were identified and used for evaluation with a hyperspectral imaging system. The hyperspectral imaging system, which was a line-scan (pushbroom) imaging system, consisted of a hyperspectral camera, fibre-optic line lights, a computer and frame grabber. The hyperspectral imaging camera consisted of a high-resolution charge coupled device (CCD) camera, a prism-grating-prism spectrograph, focusing lens, associated optical hardware and a motorised controller. The imaging system operated from about 400 to 900 nm. The hyperspectral imaging system was calibrated for wavelength, distance and percent reflectance and analysis of calibrated images at the key wavelengths indicated that single-wavelength images were inadequate for detecting contaminants. However, a ratio of images at two of the key wavelengths was able to identify faecal and ingesta contaminants. Specifically, the ratio of the 565-nm image divided by the 517-nm image produced good results. The ratio image was then further processed by masking the background and either enhancing the image contrast with a non-linear histogram stretch, or applying a faecal threshold. The results indicated that, for the limited sample population, more than 96% of the contaminants were detected. Thus, the hyperspectral imaging system was able to detect contaminants and showed feasibility, but was too slow for real-time on-line processing. Therefore, a multivariate system operating at 565 and 517 nm, which should be capable of operating at real-time on-line processing speed, should be used. Further research with such a system needs to be conducted.

Determination of the End Point of a Chemical Synthesis Process Using On-Line Measured Mid-Infrared Spectra

2000 ◽  
Vol 54 (4) ◽  
pp. 601-607 ◽  
Author(s):  
K. De Braekeleer ◽  
A. de Juan ◽  
F. Cuesta Sánchez ◽  
P. A. Hailey ◽  
D. C. A. Sharp ◽  
...  
Keyword(s):  
Steady State ◽  
Principal Component ◽  
Quantitative Information ◽  
Multivariate Curve Resolution ◽  
Synthesis Process ◽  
Synthetic Process ◽  
Mid Infrared ◽  
End Point ◽  
On Line ◽  
Projection Approach

The orthogonal projection approach (OPA), principal component analysis (PCA), and multivariate curve resolution alternating least-squares (MCR-ALS) are applied to detect the end point of an organic synthetic process monitored on-line by mid-infrared spectroscopy. The OPA dissimilarity criterion and the PCA plot are useful to follow the changes in the on-line measured spectra and to detect regions where a steady state of the synthesis is obtained. MCR-ALS is applied to obtain semi-quantitative information during the synthesis by analyzing the steady-state regions simultaneously. The concentrations of the components in the different steady-state regions are calculated with respect to their concentration in a reference steady-state region, chosen from the OPA dissimilarity and PCA plots.

Modeling strategies for pharmaceutical blend monitoring and end-point determination by near-infrared spectroscopy

2014 ◽  
Vol 473 (1-2) ◽  
pp. 219-231 ◽  
Author(s):  
Benoît Igne ◽  
Anna de Juan ◽  
Joaquim Jaumot ◽  
Jordane Lallemand ◽  
Sébastien Preys ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
End Point ◽  
Point Determination

Qualitative Analysis of Oil Sand Slurries Using On-Line NIR Spectroscopy

1996 ◽  
Vol 50 (12) ◽  
pp. 1535-1540 ◽  
Author(s):  
Waldemar I. Friesen
Keyword(s):  
Steady State ◽  
Water Content ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Principal Component ◽  
Fiber Optic Probe ◽  
Oil Sand ◽  
Plant Environment ◽  
On Line ◽  
Optic Probe

The development of a reliable on-line method to monitor process streams is important for improved process control in oil sand extraction plants. The suitability of diffuse reflectance near-infrared (NIR) spectroscopy for this purpose has been tested in a pilot plant environment. Spectra of a feed slurry flowing through a pipe were measured with the use of an on-line fiber-optic probe. Data were collected throughout a nine-hour period during which ore type and slurry water content were varied. The feasibility of monitoring feed stream conditions is demonstrated by principal component analysis of the measured spectra. Clustering of these spectra according to ore type and water content enables the detection of deviations from and transitions between steady-state conditions of the process. Estimates are given of characteristic times for the process to reach a steady state after a change in condition has been initiated. The use of artificial neural networks for classifying spectra on the basis of ore type is also illustrated.

On-line NIR monitoring during anaerobic treatment of municipal solid waste

2003 ◽  
Vol 48 (4) ◽  
pp. 9-13 ◽  
Author(s):  
M. Hansson ◽  
Å Nordberg ◽  
B. Mathisen
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Near Infrared ◽  
C:N Ratio ◽  
Nir Spectroscopy ◽  
Principal Component ◽  
Anaerobic Treatment ◽  
Operating Conditions ◽  
On Line ◽  
Process Disturbances

An anaerobic digester (8 l) was fed with the organic fraction of municipal solid waste and monitored intermittently for two years with on-line near-infrared (NIR) spectroscopy and traditional chemical parameters analysed off-line. The dynamics that occurred due to changes in substrate composition (changed C:N ratio) and changes in operating conditions (overloading) could be followed using principal component analysis of the obtained NIR-spectra. In addition, process disturbances such as failed stirring and increased foaming were readily detected by the NIR-spectra. Using PLS regression the propionate concentration could be predicted in the range 0.1-3.6 g/l, RMSEP 0.53 g/l with slope 0.74 and correlation coefficient 0.85. The response on changes in the digester fluid was reproducible and could be detected within 2.5 minutes, which can be considered as real-time monitoring.

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