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Portable, visual, and nondestructive detector integrating Vis/NIR spectrometer for sugar content of kiwifruits
摘要： A portable sugar content detector for intact kiwifruits was developed using a visible/near-infrared spectrometer over the wavelength of 350–1,100 nm as spectra collector, a tablet computer as controller, a micro-halogen lamp as light source, and a self-made “Y” shape optical fiber as light transmitter and light receiver. The software applied to collect spectra, to establish sugar content prediction model, and to predict sugar content of kiwifruits was developed by Java language. Partial least square regression model was established to determine sugar content of kiwifruits. Contrasted with the sugar content obtained by digital refractometer, the root-mean-square error of the developed detector was 0.93% in soluble solids content. The obtained sugar content using the developed detector could be given in 2.5 s. The study shows that the developed portable sugar content detector is a promising tool for on-site or in field nondestructive measurement on sugar content of kiwifruits.
关键词： kiwifruits,portable detector,Vis/NIR spectrometer,nondestructive measurement,sugar content
更新于2025-09-23 15:23:52
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Vis-NIR light-responsive photocatalytic activity of C3N4-Ag-Ag2O heterojunction-decorated carbon-fiber cloth as efficient filter-membrane-shaped photocatalyst
摘要： C3N4-decorated carbon-fiber (CF) cloth has been demonstrated to be a filter-membrane-shaped photocatalyst for degrading flowing wastewater, but it can be excited only by visible light (λ < 450 nm). To extend the photoresponse range to NIR region, herein we have designed and prepared C3N4-Ag-Ag2O heterojunctions on CF cloth. The growth of C3N4 nanosheets (thickness: 20-30 nm) on CF cloth is realized by a thermal condensation method, and then Ag/Ag2O nanoparticles (10-20 nm) are deposited on CF/C3N4 cloth by a chemical precipitation method. CF/C3N4/Ag/Ag2O cloth exhibits excellent flexibility and strong photoabsorption in a broad Vis-NIR region (400-1400 nm), wider than CF/C3N4 (absorption edge: 450 nm). Under the irradiation of 808 nm or 980 nm laser, CF/C3N4/Ag/Ag2O cloth can remove 83%/41% AO7 and 72%/38% 4-CP in 140 min respectively, significantly higher than those (33%/13% AO7 and 31%/10% 4-CP) by CF/Ag/Ag2O cloth and those (3%/1% AO7 and 0%/1% 4-CP) by CF/C3N4 cloth. Interestingly, when CF/C3N4/Ag/Ag2O cloth is used as the filter-membrane to photo-degrade the flowing wastewater (AO7, 20 mg L-1, rate: 1.5 L h-1), the removal efficiency of AO7 reaches up 97% after 8 grade reactors. Therefore, CF/C3N4/Ag/Ag2O cloth can be used as an efficient filter-membrane-shaped photocatalyst with NIR photoresponse.
关键词： CF/C3N4/Ag/Ag2O cloth,nanosheets,photocatalysis,nanoparticles,Vis-NIR
更新于2025-09-23 15:22:29
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Spectroscopy approach to methanol detection in waste fat methyl esters
摘要： Second-generation biodiesel manufactured from waste cooking oils (WCO) and inedible animal fats (AF) are one of the alternatives to the first generation (1G) vegetable oil-based biodiesel. In this study, a quality control method is proposed to evaluate methanol content in waste fat methyl esters and is based on near infrared spectroscopy (NIR) combined with multivariate analysis. More specifically, calibration models are constructed using partial least squares regression (PLS) for the prediction of methanol content in rapeseed oil methyl ester (ROME), waste cooking oil methyl ester (WCOME), chicken fat methyl ester (CFME) and pork fat methyl ester (PFME) by Vis-NIR spectrometer. The calibration models are based on the absorbance spectra and computed data from five wavelength regions of 400–2170 nm, 780–2170 nm, 1400–2170 nm, 1400–1600 nm and 1970–2170 nm. For the cases with the highest prediction ability obtained in this study, the coefficient of determination of the model's goodness-of-fit for methanol concentrations range 0–5% (v/v) was R2 N 0.990, and for concentrations 0–1% (v/v) was R2 N 0.994, indicating the spectroscopic approach effectiveness in methanol content detection relevant to the biofuel quality assessment. A pseudo-univariate limits of detection (LODpu) and quantification (LOQpu) as well as ratio of performance to deviation (RPD) were used to confirm the validity and to evaluate the practical applicability of developed models. In addition, the obtained results indicate the possibility of developing a transmission sensor for online monitoring of the production process and the quality of biofuel.
关键词： PLS calibration models,Waste cooking oil,Animal fat biofuel,Vis-NIR spectroscopy
更新于2025-09-23 15:21:21
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The application of proximal visible and near-infrared spectroscopy to estimate soil organic matter on the Triffa Plain of Morocco
摘要： Soil organic matter (SOM) is a fundamental soil constituent. The estimation of this parameter in the laboratory using the classical method is complex time-consuming and requires the use of chemical reagents. The objectives of this study were to assess the accuracy of two laboratory measurement setups of the VIS-NIR spectroscopy in estimating SOM content and determine the important spectral bands in the SOM estimation model. A total of 115 soil samples were collected from the non-root zone (0-20 cm) of soil in the study area of the Triffa Plain and then analysed for SOM in the laboratory by the Walkley–Black method. The reflectance spectra of soil samples were measured by two protocols, Contact Probe (CP) and Pistol Grip (PG)) of the ASD spectroradiometer (350-2500 nm) in the laboratory. Partial least squares regression (PLSR) was used to develop the prediction models. The results of coefficient of determination (R2) and the root mean square error (RMSE) showed that the pistol grip offers reasonable accuracy with an R2 = 0.93 and RMSE = 0.13 compared to the contact probe protocol with an R2 = 0.85 and RMSE = 0.19. The near-Infrared range were more accurate than those in the visible range for predicting SOM using the both setups (CP and PG). The significant wavelengths contributing to the prediction of SOM for (PG) setup were at: 424, 597, 1432, 1484, 1830 ,1920, 2200, 2357 and 2430 nm, while were at 433, 587, 1380, 1431, 1929, 2200 and 2345 nm for (CP) setup.
关键词： soil organic matter,SOM analysis.,VIS-NIR spectroscopy,reflectance spectra,SOM estimation
更新于2025-09-23 15:21:01
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Effect of fruit moving speed on online prediction of soluble solids content of apple using Vis/NIR diffuse transmission
摘要： The effect of fruit moving speed on online prediction of soluble solids content (SSC) of “Fuji” apples based on visible and near-infrared (Vis/NIR) spectroscopy was studied. Diffuse transmission spectra between 615 and 1,045 nm were collected with a commercial online system at speeds of 0.3 m/s (S1), 0.5 m/s (S2), and 0.7 m/s (S3). Compensation models for SSC of each speed alone (local models) and all speeds (global model) were established using partial least squares (PLS). For global model, spectra of each sample were divided into three parts (P1, P2, and P3), three kinds of spectra partition combinations (P12, P13, and P23) were established. Results showed that S3 performed better and the influence of speed on spectra greatly affected SSC evaluation accuracy between local models. Comparatively, global model was insensitive to fruit moving speed variation and effective wavelengths (EWs) selected by competitive adaptive reweighted sampling (CARS) after Savitzky–Golay smoothing (SGS) achieved better results than local models. Importantly, 36 EWs selected by CARS after SGS of global-P13 model achieved the best results with rp and RMSEP of 0.8419, 0.8895, 0.8948 and 0.6281, 0.5318, 0.5196(cid:1)Brix, respectively. Generally, global-P13 model with EWs is promisingly applied to online SSC prediction of apple by Vis/NIR diffuse transmission.
关键词： soluble solids content,online prediction,effective wavelengths,competitive adaptive reweighted sampling,partial least squares,fruit moving speed,apple,diffuse transmission,Vis/NIR spectroscopy
更新于2025-09-23 15:21:01
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Luminescence of Phosphate Glasses: P2O5-ZnO-BaF2-K2TeO3-Al2O3-Nb2O5 Doped with Sm3+ Ions for Display and Laser Material
摘要： Luminescent phosphate glasses having the composition 40P2O5-30ZnO-20BaF2-3.8K2TeO3-1.2Al2O3-5Nb2O5 in mol.% doped with 3 9 103 ppm and 4 9 103 ppm Sm2O3 were successfully prepared by a melt-quenching technique. The investigated glasses were characterized by x-ray diffraction, UV–visible–NIR, absorption, emission, and ?uorescence lifetime analysis. The radiative properties were calculated using Judd–Ofelt (J–O) spectral intensity parameters for each of the glasses, which revealed the following trend: X2 > X4 > X6. The J–O intensity parameters were used to evaluate the spontaneous emission properties including branching ratios, transition probabilities, and radiative lifetime. The value of the optical energy band gap was found to decrease with an increase in Sm3+ content, which is explained on the basis of structural changes. The calculated stimulated emission cross-section studied was high, and increased from rSE; at 1.62 lm of glasses 3.81 9 10(cid:2)21 cm2 to 4.38 9 10(cid:2)21 cm2 with increasing Sm3+ ion concentration. The structure of the glasses was investigated by computing Internuclear (cid:3) and ?eld strength F( ) and measurement of Raman spectra.
关键词： refractive index,UV–Vis–NIR,Judd–Ofelt analysis,emission cross-section,Raman spectra,Oxide glasses,density,optical energy gap
更新于2025-09-23 15:21:01
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Effect of substrate temperature on the properties of RF sputtered CdS thin films for solar cell applications
摘要： We report the effect of substrate temperature (25–300 °C) on the structural, optical and electrical properties of Cadmium Sulphide (CdS) thin films deposited onto glass substrate by Radio Frequency (RF) magnetron sputtering. The structural, morphological, optical and electrical properties of the films were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), UV–VIS-NIR spectroscopy and Hall Effect measurement respectively. The XRD studies showed that the films were polycrystalline with hexagonal wurtzite structure preferentially oriented along the (0 0 2) plane parallel to the substrate surface. The XRD data analysis further revealed the crystallite size of the nanocrystalline films i.e. 22–24 nm exhibiting the fact that crystallite size increased with increasing the substrate temperature. The FE-SEM images along with energy dispersive spectroscopy (EDS) studies confirmed the homogeneous, compact and pin-hole free surface morphology. The UV–VIS-NIR studies unveiled the optical transmittance in the range of 75–90% after 540 nm of the wavelength of light. The optical band gaps were found to be decreasing from 2.34 eV to 2.26 eV with increasing the substrate temperature. The films were characterized as n-type as evidenced by the Hall Effect measurement. The carrier mobility was found to be increasing gradually from 5.53 to 12.57 cm2/V·s by increasing the substrate temperature from room temperature to 300 °C due to the improvement of crystalline quality and grain size of the films. The results showed good optical and electrical properties of the films deposited at 300 °C which are suitable to use as window layer in thin film based solar cells.
关键词： CdS,UV–VIS-NIR,XRD,Hall effect measurement,Thin films,Substrate temperature,RF sputtering
更新于2025-09-23 15:21:01
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Construction of n-TiO2/p-Ag2O Junction on Carbon Fiber Cloth with Visa??NIR Photoresponse as a Filter-Membrane-Shaped Photocatalyst
摘要： The development of effective and reusable photocatalysts with broad-spectra activity has attracted attention. Herein, we have constructed n-TiO2/p-Ag2O junction on carbon fiber (CF) cloth as an efficient and recyclable photocatalyst. With CF cloth as the substrate, TiO2 nanorods (length: 1–2 μm) are prepared by a hydrothermal process, and the in-situ growth of Ag2O nanoparticles (10–20 nm) is then realized by chemical bath deposition route. The flexible CF/TiO2/Ag2O cloth (area: 4 × 4 cm2) shows a broad and strong photo-absorption (200–1000 nm). Under the illumination of visible-light (λ > 400 nm), CF/TiO2/Ag2O cloth can efficiently eliminate 99.2% rhodamine B (RhB), 99.4% acid orange 7 (AO7), 87.6% bisphenol A (BPA), and 89.5% hexavalent chromium (Cr6+) in 100 min, superior to CF/Ag2O cloth (83.5% RhB, 60.0% AO7, 31.2% BPA and 41.8% Cr6+). In particular, under the NIR-light illumination (980 nm laser), CF/TiO2/Ag2O cloth can remove 70.9% AO7 and 60.0% Cr6+ in 100 min, which are significantly higher than those by CF/Ag2O cloth (19.8% AO7 and 18.9% Cr6+). In addition, CF/TiO2/Ag2O cloth (diameter: 10 cm), as a filter-membrane, can effectively wipe off 94.4% flowing RhB solution (rate: ~ 1 L h? 1) at 6th filtering/degrading grade. Thus, CF/TiO2/Ag2O cloth can be used as a Vis–NIR-responded filter-membrane-shaped photocatalyst with high-efficiency for purifying wastewater.
关键词： n-TiO2/p-Ag2O junction,Filter-membrane,Photocatalyst,Vis-NIR photoresponse,Carbon fiber cloth
更新于2025-09-23 15:21:01
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Vis- and NIR-Based Instruments for Detection of Black-Tip Damaged Wheat Kernels: A Comparative Study
摘要： Black-tip (BT) is a non-mycotoxic fungus that attacks wheat kernels, forming a dark brown or black sooty area at the tip of the kernel. Visual inspection, which is the approved reference method for determining the amount of BT in wheat, requires substantial time and has high potential for subjective evaluation. Three spectrometers covering the spectral ranges 950-1636 nm (Spec1), 600-1045 nm (Spec2), and 380-780 nm (Spec3) were evaluated for their ability to predict the presence of BT. Kernels were quantified into four levels: (A) sound, (B) low black-tip symptoms (BTS), (C) high BTS, and (D) BT damaged (BTD). Discriminant classification models were developed to evaluate combinations of levels. The combinations were (1) levels A, B, C, and D separately; (2) A, B+C, and D; and (3) A+B and C+D. Spectral data for 2,760 kernels obtained from 23 hard red winter (HRW) wheat samples, each comprising 30 kernels that were visually selected for each of the four levels of black-tip severity (A, B, C, and D), were collected with each spectrometer. Discriminant calibration models for each spectrometer and classification category were developed based on (1) three combinations of 17 HRW wheat samples, with the six remaining samples used for independent validation, and (2) combinations of 20 randomly selected kernels from each of the 23 HRW wheat samples as calibration samples, with the remaining ten kernels used as validation samples. Discriminant analysis was based on five wavelengths for each model. Spectra pretreatment was the standard normal variate (SNV). Results showed that all three spectrometers were capable of detecting BT damage on wheat kernels. BT classification accuracy was observed to have been affected by wheat varieties for Spec1 and Spec2 (both with NIR wavelengths) but not for Spec3, which was entirely in the visible region. The two-category classification (A+B, C+D) provided higher accuracy than the three-category (A, B+C, D) and four-category (A, B, C, D) classifications. Based on the percent correct classification and Youden’s index, Spec2 performed better in detecting sound and BTD wheat kernels, with classification accuracies of the best two-category classification calibration model ranging from 85.6% to 87.5%, compared to Spec1 at 74.8% to 78.4% and Spec3 at 76.7% to 79.2%. This study also showed the potential of using a five-wavelength model, which equates to the potential for developing simple, less expensive, high-speed photoelectric detection instruments. These instruments can serve as important tools in plant breeding, grading, or grain processing facilities to enable BT detection and, with proper selection of wavelengths, may also find applications in simultaneous single-kernel detection, measurement, and segregation of other chemical characteristics, such as protein and starch content.
关键词： Black-tip damage,Wheat,VIS,NIR,Spectroscopy
更新于2025-09-23 15:21:01
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Diffuse Reflectance Spectroscopy (Vis-Nir-Swir) as a Promising Tool for Blue Carbon Quantification in Mangrove Soils: A Case of Study in Tropical Semiarid Climatic Conditions
摘要： The assessment of the soil organic carbon (SOC) stocks in mangrove ecosystems is essential for coastal management activities seeking the mitigation of CO2 emissions. However, the wet chemical analysis conventionally used to quantify SOC may overestimate SOC content due to oxidation of reduced compounds. This work focused on the use of diffuse reflectance spectroscopy (DRS) for predicting SOC in mangrove forest areas. When used properly, DRS may be, in some cases, a more accurate and more efficient method for the determination of SOC in mangrove soils than conventional analytical approaches. Furthermore, variable selection may simplify and improve prediction accuracy, reducing collinearity in the dataset used and allowing better SOC quantification through more interpretable and robust models.
关键词： Tropical semiarid climatic conditions,Mangrove soils,Vis-NIR-SWIR,Blue Carbon,Diffuse reflectance spectroscopy
更新于2025-09-23 15:21:01