scholarly journals Usage of Near-Infrared Spectroscopy for Inline Monitoring the Degree of Curing in RTM Processes

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3145
Author(s):  
Moritz Salzmann ◽  
Yannick Blößl ◽  
Andrea Todorovic ◽  
Ralf Schledjewski
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Linseed Oil ◽  
Reference Method ◽  
Relevant Information ◽  
Scanning Calorimetry ◽  
Rtm Process ◽  
Degree Of Curing ◽  
Cost Efficient

Near-infrared spectroscopy (NIR) was implemented in the resin transfer molding (RTM) process to inline monitor the degree of curing of a bio-based epoxy resin, which consists of epoxidized linseed oil (resin) and citric acid (hardener), respectively. A NIR micro-spectrometer was used for the development of robust calibration models using partial least squares (PLS) regression. Since the micro-spectrometer offers a smaller wavelength range compared with conventional NIR devices, and typical absorbance peaks are not directly involved in the captured data range, the results show new insights for the utilization of this technology. Different pre-treatments of the spectroscopic data have been tested, starting with different reference spectra, i.e., uncured resin and polytetrafluorethylene (PTFE), and followed by chemometrical algorithms. As a reference method for the degree of curing, direct current (DC) supported by differential scanning calorimetry (DSC) was used. The results show the potential of these cost-efficient and compact NIR micro-spectrometers for the intended inline monitoring purpose to gain relevant information feedback during the process.

Determination of gel time of prepreg in copper clad laminate industry by near infrared spectroscopy

2020 ◽  
pp. 096703352096379
Author(s):  
Qian-Fa Liu ◽  
Dan Li ◽  
Yao-De Zeng ◽  
Wei-Zhuang Huang
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Manufacturing Process ◽  
Near Infrared ◽  
Reference Method ◽  
Coefficient Of Determination ◽  
Resin Matrix ◽  
Calibration Model ◽  
Gel Time ◽  
Significant Difference

Gel time of prepreg is an important quality determinant in the manufacturing process of Copper Clad Laminate (CCL). Prepreg consists of a glass fiber reinforcement impregnated to a predetermined level with a resin matrix. In this work, near infrared spectroscopy associated with partial least squares (PLS) regression has been applied to analyse the gel time of prepreg samples in the manufacturing process. A total of 250 prepreg samples were randomly divided into a calibration set and a validation prediction set with a ratio of 4:1. The values of Root Mean Square Error of leave-one-out Cross-Validation (RMSECV) and the coefficient of determination (R2) of the calibration model was 2.95 s and 0.92 respectively, with eight PLS factors used. The results of the paired t-test revealed that there was no significant difference between the NIR method and the reference method. The analytical result showed that, NIR spectroscopy was a rapid, nondestructive, and accurate method for real-time prediction of prepreg quality in the CCL manufacturing process.

scholarly journals Simultaneous Quantification of Paracetamol and Caffeine in Powder Blends for Tableting by NIR-Chemometry

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Dana Maria Muntean ◽  
Cristian Alecu ◽  
Ioan Tomuta
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Method Development ◽  
Near Infrared ◽  
Reference Method ◽  
Active Pharmaceutical Ingredients ◽  
Pharmaceutical Ingredients ◽  
Drug Content ◽  
Powder Blends

Near-infrared spectroscopy (NIRS) is a technique widely used for rapid and nondestructive analysis of solid samples. A method for simultaneous analysis of the two components of paracetamol and caffeine from powder blends has been developed by using chemometry with near-infrared spectroscopy (NIRS). The method development was performed on samples containing 80, 90, 100, 110, and 120% active pharmaceutical ingredients, and near-infrared spectroscopy (NIRS) spectra of prepared powder blends were recorded and analyzed in order to develop models for the prediction of drug content. Many calibration models were applied in order to perform quantitative determination of drug content in powder, and choosing the appropriate number of factors (principal components) proved to be of highly importance for a PLS chemometric calibration. Once the methods were developed, they were validated in terms of trueness, precision, and accuracy. The results obtained by NIRS methods were compared with those obtained by HPLC reference method, and no significant differences were found. Therefore, the NIR chemometry methods were proved to be a suitable tool for predicting chemical properties of powder blends and for simultaneous determination of active pharmaceutical ingredients.

Studies on the Absorption Characteristics of Triglyceride in Serum by near Infrared Spectroscopy

2011 ◽  
Vol 345 ◽  
pp. 124-127
Author(s):  
Dong Min Wang ◽  
Li Jun Yao
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Principal Components ◽  
Near Infrared ◽  
Relevant Information ◽  
Least Squares Regression ◽  
Noninvasive Measurements ◽  
Calibration Models ◽  
Spectral Ranges ◽  
Absorption Characteristics

To determine the spectral ranges and extract relevant information from near infrared spectroscopy of serum in the regions of 12000-4000cm-1 when predicting triglyceride concentrations, in this paper, the first three principal components, which represent not less than 94 percents spectral information, were calculated using principal components analysis. According to this, certain spectral ranges, which contained useful absorption information, were determined based on the absorption characteristics of triglyceride and the absorption interference of water in serum. At last, three calibration models were developed coupled with the method of partial least squares regression, the results shows that there are significant improvement preferment compared the calibration based on the whole overtones spectral ranges. The analysis described here provides a method of spectral ranges selectivity by which the interference of other constituents can be eliminated easily and is useful for noninvasive measurements of the biophysical constituents in blood.

scholarly journals Aquaphotomics Reveals Subtle Differences between Natural Mineral, Processed and Aged Water Using Temperature Perturbation Near-Infrared Spectroscopy

2021 ◽  
Vol 11 (19) ◽  
pp. 9337
Author(s):  
Yasuhiro Kato ◽  
Jelena Munćan ◽  
Roumiana Tsenkova ◽  
Dušan Kojić ◽  
Masato Yasui ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Water Samples ◽  
Near Infrared ◽  
Molecular System ◽  
Relevant Information ◽  
Temperature Perturbation ◽  
Spectral Pattern ◽  
Novel Approach ◽  
Different Temperatures

Current approaches to the quality control of water are unsatisfying due to either a high cost or the inability to capture all of the relevant information. In this study, near-infrared spectroscopy (NIRS) with aquaphotomics as a novel approach was assessed for the discrimination of natural, processed and aged water samples. Temperature perturbation of water samples was employed to probe the aqueous systems and reveal the hidden information. A radar chart named an aquagram was used to visualize and compare the absorbance spectral patterns of waters at different temperatures. For the spectra acquired at a constant temperature of 30 °C, the discrimination analysis of different water samples failed to produce satisfying results. However, under perturbation by increasing the temperature from 35 to 60 °C, the absorbance spectral pattern of different waters displayed in aquagrams revealed different, water-specific dynamics. Moreover, it was found that aged processed water changed with the temperature, whereas the same processed water, when freshly prepared, had hydrogen bonded structures unperturbed by temperature. In summary, the aquaphotomics approach to the NIRS analysis showed that the water absorbance spectral pattern can be used to describe the character and monitor dynamics of each water sample as a complex molecular system, whose behavior under temperature perturbation can reveal even subtle changes, such as aging and the loss of certain qualities during storage.

Gas Chromatography as a Reference Method for Moisture Determination by Near-Infrared Spectroscopy

1998 ◽  
Vol 70 (2) ◽  
pp. 390-394 ◽  
Author(s):  
Xiangji Zhou ◽  
Patricia A. Hines ◽  
Kevin C. White ◽  
Matthew W. Borer
Keyword(s):  
Gas Chromatography ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Reference Method ◽  
Moisture Determination

Diffusive Gradients in Thin Films as a Reference Method for Assessing Soil Phosphorus by Visual and Near-Infrared Spectroscopy

2016 ◽  
Vol 45 (6) ◽  
pp. 2060-2066 ◽  
Author(s):  
Marie van Maarschalkerweerd ◽  
Songjuan Gao ◽  
Jinshun Bai ◽  
Søren Husted ◽  
Weidong Cao ◽  
...  
Keyword(s):  
Thin Films ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Soil Phosphorus ◽  
Reference Method ◽  
Diffusive Gradients
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