Study on the water content measurement of tomatoes by near infrared technique

2005 ◽  
Author(s):  
Huanyu Jiang ◽  
Yibin Ying ◽  
Yingshi Bao
Keyword(s):  
Water Content ◽  
Near Infrared ◽  
Content Measurement

scholarly journals Photoacoustic hygrometer for icing wind tunnel water content measurement: design, analysis, and intercomparison

2021 ◽  
Vol 14 (3) ◽  
pp. 2477-2500
Author(s):  
Benjamin Lang ◽  
Wolfgang Breitfuss ◽  
Simon Schweighart ◽  
Philipp Breitegger ◽  
Hugo Pervier ◽  
...  
Keyword(s):  
Water Vapor ◽  
Wind Tunnel ◽  
Water Content ◽  
Measurement Accuracy ◽  
Near Infrared ◽  
Limit Of Detection ◽  
General Description ◽  
Sampling System ◽  
Content Measurement ◽  
Better Than

Abstract. This work describes the latest design, calibration and application of a near-infrared laser diode-based photoacoustic (PA) hygrometer developed for total water content measurement in simulated atmospheric freezing precipitation and high ice water content conditions with relevance in fundamental icing research, aviation testing, and certification. The single-wavelength and single-pass PA absorption cell is calibrated for molar water vapor fractions with a two-pressure humidity generator integrated into the instrument. Laboratory calibration showed an estimated measurement accuracy better than 3.3 % in the water vapor mole fraction range of 510–12 360 ppm (5 % from 250–21 200 ppm) with a theoretical limit of detection (3σ) of 3.2 ppm. The hygrometer is examined in combination with a basic isokinetic evaporator probe (IKP) and sampling system designed for icing wind tunnel applications, for which a general description of total condensed water content (CWC) measurements and uncertainties are presented. Despite the current limitation of the IKP to a hydrometeor mass flux below 90 gm-2s-1, a CWC measurement accuracy better than 20 % is achieved by the instrument above a CWC of 0.14 g m−3 in cold air (−30 ∘C) with suitable background humidity measurement. Results of a comparison to the Cranfield University IKP instrument in freezing drizzle and rain show a CWC agreement of the two instruments within 20 %, which demonstrates the potential of PA hygrometers for water content measurement in atmospheric icing conditions.

scholarly journals Photoacoustic hygrometer for icing wind tunnel water content measurement: Design, analysis and intercomparison

2020 ◽  
Author(s):  
Benjamin Lang ◽  
Wolfgang Breitfuss ◽  
Simon Schweighart ◽  
Philipp Breitegger ◽  
Hugo Pervier ◽  
...  
Keyword(s):  
Water Vapor ◽  
Wind Tunnel ◽  
Water Content ◽  
Measurement Accuracy ◽  
Near Infrared ◽  
Limit Of Detection ◽  
General Description ◽  
Sampling System ◽  
Content Measurement ◽  
Better Than

Abstract. This work describes the latest design, calibration and application of a near-infrared laser diode-based photoacoustic (PA) hygrometer, developed for total water content measurement in simulated atmospheric freezing precipitation and high ice water content conditions with relevance in fundamental icing research, as well as aviation testing and certification. The single-wavelength and single-pass PA absorption cell is calibrated for molar water vapor fractions with a two-pressure humidity generator integrated into the instrument. Laboratory calibration showed an estimated measurement accuracy better than 3.3 % in the water vapor mole fraction range of 510–12,360 ppm (5 % from 250–21,200 ppm) with a theoretical limit of detection (3 sigma) of 3.2 ppm. The hygrometer is examined in combination with a basic isokinetic evaporator probe (IKP) and sampling system designed for icing wind tunnel application, for which a general description of total condensed water content (CWC) measurement and uncertainties are presented. Despite the current limitation of the IKP to a hydrometeor mass flux below 90 g m−2 s−1, a CWC measurement accuracy better than 20 % is achieved by the instrument above a CWC of 0.14 g m−3 in cold air (−30 °C) with suitable background humidity measurement. Results of a comparison to the Cranfield University IKP instrument in freezing drizzle and rain show a CWC agreement of the two instruments within 20 %, which demonstrates the potential of PA hygrometers for water content measurement in atmospheric icing conditions.

scholarly journals Calibration and Uncertainty Estimation for Water Content Measurement in Solids

2021 ◽  
Vol 42 (3) ◽  
Author(s):  
Rudolf Aro ◽  
Mohamed Wajdi Ben Ayoub ◽  
Ivo Leito ◽  
Éric Georgin ◽  
Benoit Savanier
Keyword(s):  
Water Vapor ◽  
Water Content ◽  
Software Tool ◽  
Uncertainty Estimation ◽  
Multiple Point ◽  
Content Measurement ◽  
Analysis Technique ◽  
Calibration Methods ◽  
Vapor Analysis ◽  
Secondary Methods

AbstractIn the field of water content measurement, the calibration of coulometric methods (e.g., coulometric Karl Fischer titration or evolved water vapor analysis) is often overlooked. However, as coulometric water content measurement methods are used to calibrate secondary methods, their results must be obtained with the highest degree of confidence. The utility of calibrating such instruments has been recently demonstrated. Both single and multiple point calibration methods have been suggested. This work compares these calibration methods for the evolved water vapor analysis technique. Two uncertainty estimation approaches (Kragten’s spreadsheet and M-CARE software tool) were compared as well, both based on the ISO GUM method.

Water absorption thermodynamics in single wood pellets modelled by multivariate near-infrared spectroscopy

Holzforschung ◽  
2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Torbjörn A. Lestander
Keyword(s):  
Water Content ◽  
Near Infrared ◽  
Calorific Value ◽  
Least Squares Regression ◽  
Wood Pellets ◽  
Differential Heat ◽  
On Line ◽  
Explained Variation ◽  
Test Sets ◽  
Content Range

Abstract Samples of wood pellets were adjusted into six water content classes from 0% to 12%. The water content in single pellets varied between 0.1% and 14.2%. Three equations were constructed to estimate the differential heat of sorption (-ΔH) values from (1) fractal-geometry, (2) isosteric, and (3) calorimetric data. The ranges in calculated -ΔH of single pellets were (1) 133–1475, (2) 315–881, and (3) 195–1188 J g-1 water, respectively, across the studied moisture content range. Partial least squares regression was used to model near-infrared (NIR) spectra from single pellets and to predict -ΔH values and water content. The explained variation in test sets for the different models ranged from 97.1% to 99.9%. The shifts in peak absorbance for two water bands indicated that frequency in overtone vibration of O-H stretching and bending decreased, when water content was raised. Simulations of mixes between pellets of differential heat values showed that released heat was up to 0.03% of the gross calorific value of wood pellets. This heat may be a major contributor to initial temperature increases in pellet stacks during storage. The results indicate that on-line NIR based predictions of differential heat in wood pellets is possible to apply in the pellet industry.

scholarly journals Water Properties of Soft Contact Lenses: A Comparative Near-Infrared Study of Two Hydrogel Materials

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Jelena Munćan ◽  
Ivana Mileusnić ◽  
Jovana Šakota Rosić ◽  
Aleksandra Vasić-Milovanović ◽  
Lidija Matija
Keyword(s):  
Water Content ◽  
Near Infrared ◽  
Contact Lenses ◽  
Polymer Network ◽  
The State ◽  
Vinyl Pyrrolidone ◽  
Soft Contact ◽  
Infrared Study ◽  
Soft Contact Lenses ◽  
State Of Water

The functionality of soft contact lenses depends strongly on the water content and their water-transport ability. This study was conducted in order to examine the state of water in two sets of soft contact lenses: VSO38, pHEMA Filcon I 1, and VSO50, copolymer of HEMA and VP Filcon II 1 (HEMA = 2-hydroxy-ethyl methacrylate; VP = vinyl pyrrolidone). Hydrogel lenses were studied using near-infrared spectroscopy and the novel Aquaphotomics approach in order to determine the state of water in materials based on their near-infrared spectra. Aquaphotomics approach investigates absorption at specific vibrational bands of water’s covalent and hydrogen bonds which can provide information on how the water structure changes with the structural change of the polymer network. Principal component analysis and specific star-chart “aquagram” were used to analyse water spectral pattern in hydrogel materials. The findings show that material VSO38 has water predominantly organized in bound state, while material with higher water content, VSO50, has more free and weakly hydrogen bonded water. Our findings define in detail exact water species existing and interacting with the polymer network. The results show qualitative and quantitative possibilities of Aquaphotomics for better modelling and understanding water behaviour in hydrogel materials.

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