Evaluation of different water absorption bands, indices and multivariate models for water-deficit stress monitoring in rice using visible-near infrared spectroscopy

2021 ◽  
Vol 247 ◽  
pp. 119104
Author(s):  
Bappa Das ◽  
Rabi N. Sahoo ◽  
Sourabh Pargal ◽  
Gopal Krishna ◽  
Rakesh Verma ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Water Absorption ◽  
Water Deficit ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Water Deficit Stress ◽  
Stress Monitoring ◽  
Multivariate Models ◽  
Absorption Bands

Near Infrared Spectroscopy of Aurichalcite (Zn,Cu2+)5(CO3)2(OH)6

2007 ◽  
Vol 15 (2) ◽  
pp. 115-121 ◽  
Author(s):  
B. Jagannadha Reddy ◽  
Ray L. Frost
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Divalent Cations ◽  
Spectral Feature ◽  
Adsorbed Water ◽  
Absorption Bands ◽  
Bending Vibrations ◽  
Show Evidence ◽  
Spectroscopy Studies

In this endeavour, near infrared spectroscopy studies show evidence of variable composition in aurichalcite minerals of zinc copper carbonate hydroxides. The observation of a broad feature in the electronic part of the spectrum around 11,500 cm−1 (870 nm) is a strong indication of Cu2+ substitution for Zn2+ in the mineral. Overtones of OH vibrations in the spectra from 7250 to 5400 cm−1 (1380–1850 nm) show strong hydrogen bonding in these carbonates. A band common to spectra of all carbonates appears near 5400 cm−1 (1850 nm) due to the combination of both OH-stretching and HOH-bending vibrations, which may be attributed to adsorbed water. Aurichalcite minerals display a spectral sequence of five absorption bands with variation of both band positions and intensities and this is the chief spectral feature observed in the range 5200–5100 cm−1 (1920–2380 nm) due to vibrational processes of the carbonate ion. The frequency shift of carbonate bands suggests the effect of divalent cations and/or variations of the Zn/Cu ratio in aurichalcite minerals.

Quantitative Analysis of Epoxy Resin Cure Reaction: A Study by Near-Infrared Spectroscopy

2002 ◽  
Vol 56 (11) ◽  
pp. 1413-1421 ◽  
Author(s):  
C. Billaud ◽  
M. Vandeuren ◽  
R. Legras ◽  
V. Carlier
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Epoxy Resins ◽  
Model Compound ◽  
Near Infrared ◽  
Curing Process ◽  
Absorption Bands ◽  
Cure Reaction ◽  
Quantitative Results ◽  
Epoxy Resin Cure

Near-infrared spectroscopy was used to quantify the cure reaction of 4,4′-methylene- bis-(2,6-diethylaniline) (MDEA)–epoxy resins (E/A = 1.4) carried out at 72 and 160 °C. The absorption bands of the functional groups of interest in MDEA–epoxy resins are assigned according to the literature. A new assignment at 6580 cm−1 is also proposed for the secondary amine: it was supported by a synthesized model compound. Two different spectrum treatments were proposed. The first one is based only on a normalization at 4610–4620 cm−1, while the second one needs the subtraction of the normalized spectrum of a post-cure sample. To follow the curing process, amines and epoxy were studied at the same time in the combination and the overtone regions. The results are compared. In the combination region, quantitative results are obtained from absorbance measurements, while in the overtone region spectrum decompositions and area measurements are necessary. Complementary and reliable information are so obtained and allow us to calculate conversions of epoxide and amine I and concentrations in amine II, amine III, hydoxyl groups, and ether links. Kinetics are also established. The curing process mechanism is at last discussed for both curing temperatures.

scholarly journals Evaluation of Chemical Quality on Juices and Wine Produced from Mamao Fruit (Antidesma Puncticulatum Miq.) Within Near-Infrared Spectroscopy

2021 ◽  
Vol 20 (5) ◽  
pp. 255-260
Author(s):  
Kongphope Chaarmart ◽  
Sureeporn Narongwongwattana ◽  
Ronnarit Rittiron ◽  
Worawat Sa-Ngiamvibool
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Cross Validation ◽  
Chemical Quality ◽  
Absorption Bands ◽  
Calibration Equation ◽  
Water Composition

The chemical quality of juices and wine produced from Mamao fruit was evaluated by Fourier transform near-infrared (FT-NIR). The calibration equation was created by the cross-validation method to be si+mulated the accuracy. Statistical values composed of correlation coefficient (R), standard error of cross-validation (SECV) and bias were used. Brix values and acidity values of Mao juice and the Brix, acidity, and alcohol values of Mao wine products were evaluated through the standard and cross-validation relation. It was found that was observed with NIR spectrometer to be absorbed in the same IR wavelength (1450 nm) which indicated that the water is the main composition. Based on FT-NIR analysis, the spectrum latices of juices and wine were revealed in the same range of the absorption bands at 1450 nm and 1940 nm to be confirmed the water composition. Also, the FT-NIR spectra from region 2258-2312 nm in Mao wine product have been predicted to the Ethanol functions.

Detection of Inorganic Wood Preservatives on Timber by near Infrared Spectroscopy

1998 ◽  
Vol 6 (A) ◽  
pp. A171-A173 ◽  
Author(s):  
Roger Feldhoff ◽  
Thomas Huth-Fehre ◽  
Karl Cammann
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Treated Wood ◽  
Untreated Wood ◽  
Wood Preservative ◽  
Wood Preservatives ◽  
Copper Salts ◽  
Absorption Bands ◽  
Waste Wood

The recycling of waste wood causes great problems due to the variety of toxic wood preservatives, varnishes and paints used. The fast and reliable distinction and sorting of treated and untreated wood on demolition sites could open new ways of wood recycling, e. g. for the production of chip boards. For this purpose, prepared wood samples treated with inorganic wood preservatives (arsenic, boron, copper salts) were investigated by near infrared-spectroscopy. In most cases, treated wood samples could be distinguished from untreated ones. Furthermore the type of wood preservative could be identified. The observed spectral features are electronic absorption bands and changes in the OH–band due to interaction with salt molecules.

A chemometric approach for moisture control in stingless bee honey using near infrared spectroscopy

2018 ◽  
Vol 26 (6) ◽  
pp. 379-388 ◽  
Author(s):  
Suelen Ávila ◽  
Polyanna Silveira Hornung ◽  
Gerson Lopes Teixeira ◽  
Márcia Regina Beux ◽  
Marcelo Lazzarotto ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Moisture Content ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Stingless Bee ◽  
Average Error ◽  
Calibration Model ◽  
Moisture Determination ◽  
Absorption Bands ◽  
Melipona Marginata

Honey is a product that is often adulterated by the addition of water. Stingless bee honey naturally has a higher moisture content than that produced by the traditional Apis mellifera. In most countries, there is a lack of quality standards and methods to characterise and assure the authenticity of stingless bee honey, which demands for the development of fast methods to assess its main properties, avoiding potential fraud. Thus, this work aimed to develop a non-destructive moisture determination method for stingless bee honey based on diffuse reflectance near infrared spectroscopy combined with chemometrics. Thirty-two honey samples from four stingless bee species ( Melipona quadrifasciata, Melipona marginata, Melipona bicolor and Scaptotrigona bipuncata) were used to develop calibration models using partial least squares regression analyses. Results revealed intense absorption bands in C–H, O–H and C–O vibrations in the spectra of stingless bee honey. The calibration model was used to predict the moisture content in honey from an external group. The prediction of the honey’s moisture showed good correlation (r2 = 0.93) with the refraction index method and an average error of 2.14%. The statistics variables for the calibration ( R2 = 0.947, SEP = 1.005 and RPD = 4.3) revealed that this model can be used to predict the moisture from stingless bee honey and that near infrared spectroscopy is a reliable tool to be applied in quality control with rapid, simple and accurate results.

Wastewater salinity assessment using near infrared spectroscopy

2013 ◽  
Vol 68 (4) ◽  
pp. 879-886 ◽  
Author(s):  
Ronald Ontiveros ◽  
Lamine Diakite ◽  
M. Edna Alvarez ◽  
Pablo Coras
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Spectral Characteristics ◽  
Visible Region ◽  
Coefficient Of Determination ◽  
Absorption Bands ◽  
Channel Network ◽  
Spectral Signatures ◽  
Wastewater Samples

The visible and near infrared spectroscopy is a fast and inexpensive non-destructive technique for the prediction of concentrations of salts in wastewater. Conventional chemical methods are usually used, which are very accurate, take more time and require special techniques for sampling, storing and pretreatment of wastewater. In this work we studied the spectral characteristics of water and the effect of salts on the perturbations in the water absorption bands. The generation of multiple regression models with principal components was carried out on standard solutions with composition of salts similar to that of wastewater samples taken along the drainage channel network of the Mexico City Metropolitan Area. The spectral signatures were obtained in situ and in the laboratory using a portable high-resolution spectroradiometer (ASD FieldSpec 3). The prediction model generated showed high precision in the estimation of salinity in wastewater, a coefficient of determination of 89.6% and a low root mean square error of 0.12‰. Other compounds, which are not discussed here, cause distortion of the absorption bands of water at wavelengths less than 900 nm or near the visible region, while our results showed distortions in the water spectrum at higher wavelengths (>1,000 nm).

Chemical Changes to Woody Polymers Due to High-Temperature Thermal Treatment Assessed with near Infrared Spectroscopy

2016 ◽  
Vol 24 (6) ◽  
pp. 555-562 ◽  
Author(s):  
Jakub Sandak ◽  
Anna Sandak ◽  
Ottaviano Allegretti
Keyword(s):  
Infrared Spectroscopy ◽  
Thermal Treatment ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Treatment Temperature ◽  
Absorption Bands ◽  
Chemical Changes ◽  
Novel Method ◽  
Treatment Procedures ◽  
Original Approach

Near infrared spectroscopy and an original approach for visualisation of spectra are proposed here for characterisation of vacuum thermally modified samples of eight wood species representing softwoods and hardwoods. Significant changes in absorption bands were observed in conjunction with an increase of treatment temperature. A novel method for visualisation of the degradation patterns (xylograms) is capable of highlighting peculiarities in chemical changes to woody polymers due to the thermal treatment. This method also allows observation of kinetics and permits comparison of thermal stability of investigated species. Such knowledge might be helpful for further optimisation of thermal treatment procedures at an industrial scale. Furthermore, xylograms as a simple and illustrative method might be suitable for visualisation of other modification processes of wood as well as of other materials.

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