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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
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Towards an optical diagnostic system for otitis media using a combination of otoscopy and spectroscopy
摘要： An improved method, where conventional otoscope investigation of human suspicious otitis media is combined with diffuse reflectance spectroscopy and gas in scattering media absorption spectroscopy (GASMAS) is being developed. Otitis media is one of the most common infectious diseases in children, whose Eustachian tube connecting the middle ear with the nasal cavity is more horizontal than for adults, which leads to impaired fluid drainage. At present, the use of an otoscope to visually observe possible changes in the tympanic membrane appearance is the main diagnostics method for otitis media. Inaccurate diagnosis related to similar symptoms, and the difficulty for small children to describe the condition experienced, frequently leads to over-prescription of antibiotics and alarming increase in bacterial resistance development. More accurate diagnostic methods are highly desirable. Diffuse reflectance spectroscopy is a non-invasive quantitative spectroscopic technique that enables to objectively quantify changes in the hemoglobin content of the tympanic membrane related to inflammation. If an infection is present, the ventilatory function of the Eustachian tube is frequently impaired and the middle-ear cavity will be filled with fluid. GASMAS, a non-invasive detection method, can non-invasively determine if gas is replaced by fluid in the middle-ear cavity.
关键词： otitis media,otoscope,diffuse reflectance spectroscopy,diagnostics,GASMAS,ear infection
更新于2025-09-19 17:15:36
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Identification of tea varieties by mid‐infrared diffuse reflectance spectroscopy coupled with a possibilistic fuzzy c‐means clustering with a fuzzy covariance matrix
摘要： Mid-infrared diffuse reflectance spectroscopy was used to rapidly and nondestructively identify tea varieties together with the proposed possibilistic fuzzy c-means (PFCM) clustering with a fuzzy covariance matrix. The mid-infrared diffuse reflectance spectra of 96 tea samples with three different varieties (Emeishan Maofeng, Level 1, and Level 6 Leshan trimeresurus) were acquired using the FTIR-7600 infrared spectrometer. First, multiplicative scatter correction was implemented to pretreat the spectral data. Second, principal component analysis was employed to compress the mid-infrared diffuse reflectance spectral data after preprocessing. Third, linear discriminant analysis was utilized for extracting the identification information required by the fuzzy clustering algorithms. Ultimately, the fuzzy c-means (FCM) clustering, the allied fuzzy c-means (AFCM) clustering, the PFCM clustering, and the PFCM clustering with a fuzzy covariance matrix were used to cluster the processed spectral data, respectively. The highest identification accuracy of the PFCM clustering with a fuzzy covariance matrix reached at 100% compared with those of FCM (96.7%), AFCM (94.9%), PFCM (96.3%), and partial least squares discrimination analysis (PLS-DA) algorithm (33.3%). It is sufficiently demonstrated that the mid-infrared diffuse reflectance spectroscopy coupled with the PFCM clustering with a fuzzy covariance matrix was a valid method for identifying tea varieties.
关键词： possibilistic fuzzy c-means clustering,tea varieties,Mid-infrared diffuse reflectance spectroscopy,fuzzy covariance matrix,nondestructive detection
更新于2025-09-11 14:15:04
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Redox Dynamics of Pd Supported on CeO <sub/>2</sub> -ZrO <sub/>2</sub> during Oxygen Storage/Release Cycles Analyzed by Time-Resolved <i>In Situ</i> Reflectance Spectroscopy
摘要： In situ time-resolved diffuse reflectance spectroscopy provided the redox dynamics of Pd nanoparticles supported on an oxygen storage material CeO2-ZrO2 (CZ) under lean/rich perturbation conditions. Because the reflectance at 450 nm is sensitive to the Pd oxidation state but is not affected by the redox of Ce3+/Ce4+ species of CZ, the real-time Pd redox can be monitored every second during oxygen storage/release in simulated engine combustion exhaust gas (CO–C3H6–NO–O2) corresponding to gasoline air-to-fuel ratios of 14.1 (rich) and 15.0 (lean). Although a large amount of O2 was stored by CZ upon the rich-to-lean switch, the rate of Pd oxidation during this event was found to be much more moderate compared to that with a reference catalyst, Pd/Al2O3. Because rapid oxygen uptake by CZ reduces the local O2 partial pressure near the surface, the oxidation of Pd should be retarded. This can preserve active metallic Pd and thus contribute to longer retention of high NO reduction efficiency even under the lean condition. However, the reduction of Pd oxide (PdO) upon reverse (lean-to-rich) switching occurred at a similar rate irrespective of the support material. The metallic Pd deposits near the interface with CZ promote the catalytic activation of reducing gases (CO and C3H6), resulting in significant oxygen release from CZ. The temperature dependence of the redox rate demonstrates that oxidation of metallic Pd to PdO is much slower than reduction over Pd/CZ, whereas oxidation is faster than reduction over Pd/Al2O3. The preservation of active metallic Pd under lean/rich perturbation conditions is another key role of the oxygen storage CZ co-catalyst.
关键词： CeO2-ZrO2,in situ diffuse reflectance spectroscopy,oxygen storage/release,redox dynamics,Pd nanoparticles
更新于2025-09-10 09:29:36
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Surface-enhanced Raman spectroscopy (SERS) in cotton fabrics analysis
摘要： This article presents some aspects of application the dispersive Micro-Raman Spectroscopy in textile fibers analysis. Research were dedicated to the methodology of surface enhancement Raman spectroscopy (SERS) studies on cotton fabric and possibility of its application in fibers characterization. Studies were carried out on dyed cotton fabrics modified by silver nanowires (AgNWs). Three reactive dyes (blue, yellow, red) and four color intensities (0.5%, 1%, 2% and 5%) were used. AgNWs colloid was deposited on undyed and dyed cotton fabrics by dipping and drying method. Dyed fabrics were examined by spectroscopic methods: FTIR ATR, Raman, UV-Vis Diffuse Reflectance Spectroscopy, Fluorescence Spectroscopy. Raman signal enhancement phenomena occurring on the silver nanoparticles increases the possibility of fiber and dye identification especially in the case of dyes used in cotton dyeing reveals fluorescence.
关键词： UV-Vis Diffuse Reflectance Spectroscopy,SERS,Fluorescence Spectroscopy,reactive dyes,FTIR ATR,Micro-Raman spectroscopy,Cotton fibers
更新于2025-09-09 09:28:46