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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - An Approach to Tree Species Classification Using Voxel Neighborhood Density-Based Subsampling of Multiscan Terrestrial Lidar Data
摘要： The knowledge on the species of individual trees is ineluctable for accurate forest parameter estimation and related studies. Terrestrial Laser Scanning (TLS) remote sensing systems acquire a huge number of point samples that contain very accurate and detailed three dimensional (3D) information of tree structures. Every tree species has unique internal and external crown structural characteristics that can be modeled from its TLS data. However, methods in the state of the art show reduced performance due to inaccurate modeling of tree structures such as the crown, and the branch, and poor selection of features. The proposed method leverages on the fine internal and external crown structural information in TLS data to achieve species classification. We remove noise and stem points in TLS data using a novel voxel neighborhood density-based technique. Internal and external crown geometric features derived from the branch level, and the crown level, respectively, are provided to a nonlinear Support Vector Machines (SVM) to achieve species classification, and evaluate feature relevance. All experiments were conducted on a set of 75 manually delineated trees belonging to the Spruce, the Pine, and the Birch species.
关键词： Tree Species,Remote Sensing,Classification,Terrestrial Laser Scanning (TLS),Light Detection and Ranging (LiDAR)
更新于2025-09-10 09:29:36
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Role of reactive oxygen species in the visible light photocatalytic mineralization of rhodamine B dye by P25–carbon dot photocatalyst
摘要： An undoped carbon dot (C-dot) with very high photoluminescence quantum yield (PLQY) (25%) and the P25/C-dot composite photocatalyst with improved visible light (VL) photocatalytic activity is reported. The composite exhibits superior VL photodegradation (PD) towards the dyes (RhB) and methyl orange compared to that of control P25. The effect of reactive oxygen species (ROS) is studied in the VL PD of the dye RhB using scavengers. Our study suggests that the ROS responsible for the mineralization of RhB is hydroxyl radical (?OH) and the combination of ?OH and singlet oxygen (1O2) has a synergistic effect on the mineralization of RhB. The ?OH formation is thought to be through the secondary reactions of ROS. Enhancement in the VL PD and the formation of ?OH are attributed to the presence of C-dot. The results suggest that C-dot assists the formation of ?OH through secondary reactions.
关键词： photocatalytic activity,mineralization,reactive oxygen species,visible light,rhodamine B,carbon dot
更新于2025-09-10 09:29:36
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Ciprofloxacin degradation in UV/chlorine advanced oxidation process: Influencing factors, mechanisms and degradation pathways
摘要： Ciprofloxacin (CIP) is a widely used third generation fluoroquinolone antibiotics, and has been often detected in wastewater treatment plants. Finding an effective way to remove them from wastewater is of great concern. Ultraviolet (UV)/chlorine advanced oxidation process (AOP) has many advantages in micropollutant removal. In this study, CIP degradation in UV/chlorine process was investigated. Only 41.2% of CIP was degraded by UV photolysis and 30.5% by dark chlorination in 30 min, while 98.5% of CIP was degraded by UV/chlorine process in 9 min. HCO3- had markedly inhibition, NO3- and SO42- had slight inhibition, and Cl- had a marginal inhibition on the CIP degradation in UV/chlorine system. The degradation of CIP in UV/chlorine process was mainly attributed to the attack of reactive species. The relative contributions of hydrated electrons (eaq-), hydroxyl radicals (HO.), chlorine atoms (Cl.), and UV photolysis were investigated. Under neutral condition in aqueous solution, CIP degradation had highest pseudo first-order reaction rate constants, in which eaq- followed by Cl., HO., and UV photolysis. The intermediates and byproducts were identified and the degradation pathway was proposed. The total organic chlorine (TOCl) and biotoxicity were further assessed. CIP and natural organic matters (NOMs) were removed efficiently in real water. UV/chlorine showed the potential for the wastewater treatment containing CIP.
关键词： advance oxidation process,UV/chlorine process,UV photolysis,reactive species,wastewater,Ciprofloxacin
更新于2025-09-10 09:29:36
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Type II heterojunction in hierarchically porous zinc oxide/graphitic carbon nitride microspheres promoting photocatalytic activity
摘要： Graphitic carbon nitride (g-C3N4) is a visible light active semiconductor. However, low conductivity and high recombination rate of photogenerated electrons and holes limit its application in photocatalysis. In this work, we design and synthesize hierarchically porous zinc oxide/ graphitic carbon nitride (ZnO/g-C3N4) microspheres with type-II heterojunction to effectively degrade rhodamine B (RhB) via increasing the charge-separation efficiency. The ultraviolet-visible (UV-Vis) absorption spectra, Mott-Schottky plots and valence band X-ray photoelectron spectroscope confirm the formation of type-II heterojunction between ZnO nanocrystals and g-C3N4 nanosheets. As a result, the 1.5-ZnO/g-C3N4 composite (the mass ratio of zinc acetate dihydrate to g-C3N4 is 1.5) exhibits the highest photocatalytic activity with good stability and higher photocatalytic degradation rate comparing to pure g-C3N4 and pure ZnO. In addition, our results confirm that ?O2- and h+ are the main active species for ZnO/g-C3N4 in degradation of RhB.
关键词： Active species,Heterojunction,Photocatalytic activity,Hierarchically porous structure,ZnO/g-C3N4
更新于2025-09-10 09:29:36
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Raman spectroscopic characterisation of photo-active keratin doped with Methylene Blue for wound dressings and tissue engineering
摘要： BACKGROUND: The design of wound dressings with extraordinary functionalities that fully address the problem of wound healing is an ambitious challenge in biomedical ?eld. Keratin is a protein most abundant in nature, being the major component of wool, feather, hair, etc., with promising applications in biomedical and regenerative medicine ?elds. A high level of antibacterial functionality is another desirable property for applications in biomedical ?eld in response to the increasing resistance of bacteria to antibiotics. One of the emerging methods of disinfection and sterilization is the antimicrobial photodynamic therapy (APDT), which uses light combined to a photosensitizer and oxygen to produce phototoxic species. OBJECTIVE: Biomatrices (photo-active keratin) made of wool keratin functionalized with methylene blue, a powerful photo-sensitizer, have been developed and tested as systems that combine the bioactive properties with the antimicrobial photodynamic functionality. METHODS: The biomatrix resistance to photo-degradation and the formation of reactive oxygen species were evaluated by spectroscopic methods, whereas the antibacterial properties were tested towards gram-positive bacteria. RESULTS: The Raman analysis revealed that speci?c damages occur at sensitive amino acid sites, selectively, rather than indiscriminately. However, keratin resulted to be a suitable biomaterial for APDT, since it has enough resistance to photo-degradation and the radical-induced oxidation is not able to induce strong structural changes in the protein. CONCLUSIONS: The results clearly indicate the potential use of these novel photo-active keratin biomatrices in wound dressing and tissue engineering.
关键词： reactive oxygen species,Raman spectroscopy,antimicrobial photodynamic activity,Keratin
更新于2025-09-10 09:29:36
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Discrimination of wood and charcoal from six Caatinga species by near-infrared spectroscopy
摘要： Correct identification of species in wood and charcoal commerce is important, and rapid and nondestructive evaluation based on near-infrared techniques can be a good alternative. Four trees from Combretum leprosum, Croton argyrophylloides, Jatropha mutabilis, Luetzelburgia auriculata, Mimosa tenuiflora and Poincianella bracteosa, were cut in a natural forest in the municipality of Coremas, Paraíba state and stem discs with thickness of about 80 mm were taken at 0, 25, 50, 75 and 100% of commercial height. For charcoal production, each sample was wrapped in aluminum foil and carbonized in a muffle furnace, with a final temperature of 450 °C and a heating rate of 1,66 °C min1. Spectra were collected directly from sample surface. The best pretreatment was second derivative, while the best classification method was PCA-LDA, and the analysis of full spectra (4000-10000 cm-1) was indicated. In classification, there was no difference between surfaces where spectra was collected, so in practice, in commercial control for example, the information can be obtained from any surface. For rapid analysis for purposes of control of forest practices or illegal commerce, spectra collected directly from wood and charcoal can be applied to distinguish these six Caatinga species.
关键词： species distinction,spectroscopy,Classification method,wood commerce,wood identification
更新于2025-09-10 09:29:36
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Photocatalytic decomposition of methanol-water solution over N-La/TiO2 photocatalysts
摘要： Manuscript focuses on the role of N-doping on photocatalytic behaviour of N-La/TiO2 materials in decomposition of methanol-water solution. N-La/TiO2 materials were prepared with approximately the same amounts of La (0.14–0.16 wt%) and di?erent amounts of N (0.33–0.97 at. % of surface nitrogen). Addition of small amount of surface nitrogen signi?cantly increased the amount of hydrogen produced for N-La/TiO2 photocatalysts in contrast to TiO2 and La/TiO2. The chemical composition (XRF, AAS, XPS), structural (XRD, Raman, XPS, TEM), textural (N2-adsorption) and optical properties (DRS) were studied. N-La/TiO2 materials showed approximately the same speci?c surface area and crystallite size, with values ranging for La/TiO2 and N/TiO2 photocatalysts. For studied N-La/TiO2 photocatalysts, the photocatalytic activity increased with the increasing amount of surface nitrogen (interstitial positions, XPS), and subsequently with increasing amount of oxygen vacancies (Raman spectroscopy) and decreasing amount of surface oxygen species (surface lattice O species and hydroxyl groups evidenced by XPS).
关键词： Surface oxygen species,N-La/TiO2,Oxygen vacancies,Hydrogen production
更新于2025-09-10 09:29:36
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Effective Removal of Emerging Dissolved Cyanotoxins from Water using Hybrid Photocatalytic Composites
摘要： Harmful algal blooms are occurring more frequently in fresh water throughout the world. Certain cyanobacteria can produce and release potent toxic compounds, known as cyanotoxins, such as microcystins, cylindrospermopsin, saxitoxin, and anatoxin-a, and as such they have become a human and environmental health concern. Hybrid photocatalytic composites (HPCs) comprising carbon nanotubes on the surface of TiO2 nanotubes were designed in this study. The HPCs have a selective adsorption capacity to cyanotoxins and provide photocatalytic activity to produce reactive oxygen species for the degradation of cyanotoxins. HPCs with 5.2 mg carbon nanotubes/cm2 showed an excellent removal efficiency of microcystins-LR (> 95%) at 55.6 L/m2/hr/bar. The HPCs more efficiently removed the relatively larger and more hydrophobic cyanotoxins (i.e., microcystin-LR) than the relatively smaller and more hydrophilic compounds (such as cylindrospermopsin, saxitoxin, and anatoxin-a). With a further increased in the carbon nanotube content to 8.6 mg/cm2, the adsorption capacity of the HPCs for cyanotoxins increased to 70.6% for MC-LR. However, there was significant decrease in the photocatalytic activity of the HPCs for production of reactive oxygen species, and consequently a decrease in the degradation of cyanotoxins. It is considered that this device could be used to provide complete rejection of particles and pathogens, and also to significantly reduce trace organic compounds and harmful algal toxins in emergency water supplies.
关键词： Adsorption,Harmful algal blooms,Cyanotoxins,Photocatalytic activity,Reactive oxygen species,Hybrid photocatalytic composites
更新于2025-09-10 09:29:36
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Automatic Identification of Butterfly Species Based on Gray-Level Co-occurrence Matrix Features of Image Block
摘要： In recent years, automatic identi?cation of butter?y species arouses more and more attention in di?erent areas. Because most of their larvae are pests, this research is not only meaningful for the popularization of science but also important to the agricultural production and the environment. Texture as a notable feature is widely used in digital image recognition technology; for describing the texture, an extremely e?ective method, gray-level co-occurrence matrix (GLCM), has been proposed and used in automatic identi?cation systems. However, according to most of the existing works, GLCM is computed by the whole image, which likely misses some important features in local areas. To solve this problem, this paper presents a new method based on the GLCM features extruded from three image blocks, and a weight-based k-nearest neighbor (KNN) search algorithm used for classi?er design. With this method, a butter?y classi?cation system works on ten butter?y species which are hard to identify by shape features. The ?nal identi?cation accuracy is 98%.
关键词： automatic identi?cation,features of image block,butter?y species,gray-level co-occurrence matrix (GLCM)
更新于2025-09-09 09:28:46
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Simultaneous species and sex identification of silkworm pupae using hyperspectral imaging technology
摘要： To obtain high-quality raw silk and improve the economic values of sericulture industry, sex needs to be discriminated first before cross-breeding. Much work has been reported about sex identification. However, to realize automatic separation of silkworm pupae, the species also needs to be classified, which no research has ever explored. Hence, this paper studied the feasibility of visible and near-infrared hyperspectral imaging technology to identify the species and sex of silkworm pupae. 288 hyperspectral images of silkworm pupae were collected and the average spectra were extracted from the region of interest, around the tail region of silkworm pupae. Successive projection algorithm was served as a variable selection method to choose the optimal wavelengths from the full spectra. At the same time, principal component analysis was used to choose the characteristic images. Then, the gray-level co-occurrence matrix was implemented on the first three principal component images (accounted for 99.05% of the total variances) to extract 48 textural features. Partial least squares discriminant analysis and support vector machine models were built, respectively, based on the spectral data, textural data and fusion data that included spectral and textural data, in which the support vector machine model based on the fusion data, gave the best species and sex identification result with an accuracy of 95.83%. It demonstrated that the hyperspectral imaging technology could be a new and nondestructive method to replace the manual work.
关键词： silkworm pupa,species,identification sex,Hyperspectral imaging
更新于2025-09-09 09:28:46