scholarly journals Experimental Analysis on the Optimal Excitation Wavelength for Fine-Grained Identification of Refined Oil Pollutants on Water Surface Based on Laser-Induced Fluorescence

2021 ◽  
Author(s):  
Ming Xie ◽  
Yunpeng Jia ◽  
Ying Li ◽  
Xiaohua Cai ◽  
Kai Cao
Keyword(s):  
Experimental Analysis ◽  
Water Surface ◽  
Laser Induced Fluorescence ◽  
Excitation Wavelength ◽  
Refined Oil ◽  
Fine Grained ◽  
Optimal Excitation

scholarly journals Experimental analysis on the optimal excitation wavelength for fine-grained identification of refined oil pollutants on water surface based on laser-induced fluorescence

2021 ◽  
Author(s):  
Ming Xie ◽  
Yunpeng Jia ◽  
Ying Li ◽  
Xiaohua Cai ◽  
Kai Cao
Keyword(s):  
Oil Spill ◽  
Theoretical Basis ◽  
Water Surface ◽  
Laser Induced Fluorescence ◽  
Excitation Wavelength ◽  
Refined Oil ◽  
Fine Grained ◽  
Optimal Excitation ◽  
Oil Spill Identification

Abstract Laser-induced fluorescence (LIF) is an effective, all-weather oil spill identification method that has been widely applied for oil spill monitoring. However, the distinguishability on oil types is seldom considered while selecting excitation wavelength. This study is intended to find the optimal excitation wavelength for fine-grained classification of refined oil pollutants using LIF by comparing the distinguishability of fluorometric spectra under various excitation wavelengths on some typical types of refined-oil samples. The results show that the fluorometric spectra of oil samples significantly vary under different excitation wavelengths, and the four types of oil applied in this study are most likely to be distinguished under the excitation wavelengths of 395 nm and 420 nm. This study is expected to improve the ability of oil types identification using LIF method without increasing time or other cost, and also provides theoretical basis for the development of portable LIF devices for oil spill identification.

scholarly journals Experimental analysis on the optimal excitation wavelength for fine-grained identification of refined oil pollutants on water surface based on laser-induced fluorescence

2021 ◽  
Author(s):  
Ming Xie ◽  
Yunpeng Jia ◽  
Ying Li ◽  
Xiaohua Cai ◽  
Kai Cao
Keyword(s):  
Oil Spill ◽  
Theoretical Basis ◽  
Water Surface ◽  
Laser Induced Fluorescence ◽  
Excitation Wavelength ◽  
Refined Oil ◽  
Fine Grained ◽  
Optimal Excitation ◽  
Oil Spill Identification

Abstract Laser-induced fluorescence (LIF) is an effective, all-weather oil spill identification method that has been widely applied for oil spill monitoring. However, the distinguishability on oil types is seldom considered while selecting excitation wavelength. This study is intended to find the optimal excitation wavelength for fine-grained classification of refined oil pollutants using LIF by comparing the distinguishability of fluorometric spectra under various excitation wavelengths on some typical types of refined-oil samples. The results show that the fluorometric spectra of oil samples significantly vary under different excitation wavelengths, and the four types of oil applied in this study are most likely to be distinguished under the excitation wavelengths of 395 nm and 420 nm. This study is expected to improve the ability of oil types identification using LIF method without increasing time or other cost, and also provides theoretical basis for the development of portable LIF devices for oil spill identification.

Emissions of porewater compounds and gases from the subaquatic sediment disposal site “rodewischhafen”, hamburg harbour

1998 ◽  
Vol 37 (6-7) ◽  
pp. 87-93 ◽  
Author(s):  
M. Kussmaul ◽  
A. Groengroeft ◽  
H. Koethe
Keyword(s):  
Water Surface ◽  
Disposal Site ◽  
Dredged Material ◽  
Water Fluxes ◽  
Gas Emissions ◽  
Fine Grained ◽  
Deposit Surface ◽  
Groundwater Samples ◽  
High Concentrations ◽  
Mud Deposit

In the year 1993 a confined and unused harbour basin was used to store 290,000 m3 of fine-grained dredged material from Hamburg harbour. About 70% of the deposit surface was water covered. The edge areas were above the water table and covered with reed. Emissions of dissolved compounds into the groundwater, as well as surface gas emissions were measured from 1994 to 1996. As indicators for water fluxes from the deposit we used NH4+ and HCO3− because of their high concentrations in mud porewater in comparison to groundwater. The average concentrations of NH4+ and HCO3− in the porewater increased during 2 years from 85 to 250 mg NH4+ 1−1 and from 2.0 to 3.1 g HCO3− 1−1, while the groundwater samples showed constant values of 8 mg NH4+ 1−1 and 0.7 g HCO3− 1−1. Furthermore, the average gas emissions over the water surface were 3.2 g CH4 m−2 d−1 and 0.8 g CO2 m−2 d−1. In contrast, no methane and 3.0 g CO2 m−2 d−1 were emitted from land areas. The results indicated, that there were no significant emissions of mud porewater compounds into the groundwater but high CH4-emissions over the water covered surface of the mud deposit.

scholarly journals Remote Laser Induced Fluorescence of Soils and Rocks

Photonics ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 411
Author(s):  
Vasily N. Lednev ◽  
Alexey F. Bunkin ◽  
Sergey M. Pershin ◽  
Mikhail Ya. Grishin ◽  
Diana G. Artemova ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Fluorescence Spectra ◽  
Space Exploration ◽  
Laser Induced Fluorescence ◽  
Excitation Wavelength ◽  
Extraterrestrial Life ◽  
Future Space ◽  
Lidar Sensing ◽  
First Time ◽  
Different Soils

The laser induced fluorescence spectroscopy was systematically utilized for remote sensing of different soils and rocks for the first time, to the best of our knowledge. Laser induced fluorescence spectroscopy measurements were carried out by the developed nanosecond LIDAR instrument with variable excitation wavelength (355, 532 and 1064 nm). LIDAR sensing of different Brazil soil samples have been carried out in order to construct a spectral database. The laser induced fluorescence spectra interpretation for different samples has been discussed in detail. The perspectives of LIDAR sensing of organic samples deposited at soils and rock have been discussed including future space exploration missions in the search for extraterrestrial life.

Investigation on the Preparation and Properties of Monodispersed Spherical Y2O3:Dy3+ Phosphor

2017 ◽  
Vol 726 ◽  
pp. 255-260 ◽  
Author(s):  
Jin Kai Li ◽  
Zhong Peng Liu ◽  
Jiang Fan Luo ◽  
Xin Bo Ma ◽  
Xin Teng ◽  
...  
Keyword(s):  
Blue Emission ◽  
Yellow Emission ◽  
Excitation Wavelength ◽  
Homogeneous Precipitation ◽  
Fluorescent Properties ◽  
Spherical Morphology ◽  
Rare Earth Nitrate ◽  
Urea Content ◽  
Phase Pure ◽  
Optimal Excitation

The oxide phosphor (Y1-xDyx)2O3(x=0-0.1) was obtained by calcining their respective precursors synthesized by homogeneous precipitation technique using rare earth nitrate as mother salt and urea as precipitating agent. The particle shape/size, fluorescent properties (especially the influence of Dy3+ concentration and calcination temperature) of the product was studied in detail. The results showed that the precursors exhibit monodisperse spherical morphology whose size can be controlled by adjusting the urea content. The phase pure (Y1-xDyx)2O3 can be obtained by calcining precursor at least 600 °C, and the monodisperse spherical morphology can be kept at even high temperature of 1000 °C. The (Y1-xDyx)2O3 phosphors exhibit strong yellow emission at ~577 nm (4F9/2→6H13/2 transition of Dy3+) and blue emission at ~491 nm (4F9/2→6H15/2 transition of Dy3+) upon optimal excitation wavelength of ~352 nm. The quenching concentration of Dy3+ was determined to be ~2 at% (x=0.02). The emission intensity of (Y1-xDyx)2O3 phosphors can be improved with the temperature and particle size increasing

Laser-induced fluorescence (LIF) of lignin and lignin model compounds in Raman spectroscopy

Holzforschung ◽  
2013 ◽  
Vol 67 (5) ◽  
pp. 531-538 ◽  
Author(s):  
Anni Lähdetie ◽  
Paula Nousiainen ◽  
Jussi Sipilä ◽  
Tarja Tamminen ◽  
Anna-Stiina Jääskeläinen
Keyword(s):  
Raman Spectroscopy ◽  
Structural Information ◽  
Laser Induced Fluorescence ◽  
Excitation Wavelength ◽  
Raman Signal ◽  
Model Compounds ◽  
Worst Case ◽  
Lignin Model Compounds ◽  
Key Factor ◽  
Lignin Model

Abstract Raman spectroscopy is a technique that provides structural information on lignin and other components of wood and pulp in situ. However, especially lignin-containing samples may produce laser-induced fluorescence (LIF) that overlaps with Raman bands. In the worst case, this background signal can overwhelm the weaker Raman signal completely. In this study, the LIF of lignin was investigated with the excitation wavelength 532 nm applied in Raman spectroscopy to clarify the correlations between lignin structure and LIF intensity. Raman spectroscopic analyses with lignin model compounds illustrated that the 5-5′ structures induce LIF. It was also shown that the intensity of LIF was significantly less intense when the 5-5′ model compound was structurally rigid (as in dibenzodioxocin) compared with the flexible simple counterpart. The comparison between the free phenolic model compounds with the methylated analogue showed that the presence of the free phenolic structure was not a prerequisite for LIF. It was thus concluded that the conformation of the molecule is the key factor with respect to fluorescence. The role of conformational aspects was further investigated by comparing wood with chemical pulps and isolated lignins.

An Experimental Analysis of a New Interval-Based Mutation Operator

2015 ◽  
Vol 14 (03) ◽  
pp. 1550018 ◽  
Author(s):  
K. Liagkouras ◽  
K. Metaxiotis
Keyword(s):  
Experimental Analysis ◽  
Pareto Front ◽  
Computational Experiments ◽  
Coarse Grained ◽  
Mutation Operator ◽  
Fine Grained ◽  
Initial Stage ◽  
Speed Up ◽  
Better Than

In this paper, we present a novel Interval-Based Mutation (IBMU) operator. The proposed mutation operator is performing coarse-grained search at initial stage in order to speed up convergence toward more promising regions of the search landscape. Then, more fine-grained search is performed in order to guide the solutions towards the Pareto front. Computational experiments indicate that the proposed mutation operator performs better than conventional approaches for solving several well-known benchmarking problems.

scholarly journals THE EFFECTIVE OF DIFFERENT EXCITATION WAVELENGTHS ON THE IDENTIFICATION OF PLANT SPECIES BASED ON FLUORESCENCE LIDAR

2016 ◽  
Vol XLI-B1 ◽  
pp. 147-150
Author(s):  
Jian Yang ◽  
Wei Gong ◽  
Shuo Shi ◽  
Lin Du ◽  
Jia Sun ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Plant Species ◽  
Fluorescence Spectra ◽  
Principal Component ◽  
Laser Induced Fluorescence ◽  
Support Vector ◽  
Excitation Wavelength ◽  
Lidar System ◽  
Excitation Light

Laser-induced fluorescence (LIF) served as an active technology has been widely used in many field, and it is closely related to excitation wavelength (EW). The objective of this investigation is to discuss the performance of different EWs of LIF LiDAR in identifying plant species. In this study, the 355, 460 and 556 nm lasers were utilized to excite the leaf fluorescence and the fluorescence spectra were measured by using the LIF LiDAR system built in the laboratory. Subsequently, the principal component analysis (PCA) with the help of support vector machine (SVM) was utilized to analyse fluorescence spectra. For the three EWs, the overall identification rates of the six plant species were 80 %, 83.3 % and 90 %. Experimental results demonstrated that 556 nm excitation light source is superior to 355 and 460 nm for the classification of the plant species for the same genus in this study. Thus, an appropriate excitation wavelength should be considered when the LIF LiDAR was utilized in the field of remote sensing based on the LIF technology.

Pilot Study of Mechanical Waves Passing through Fine-Grained Cement Composite during the Early Hydration Process

2020 ◽  
Vol 846 ◽  
pp. 243-247
Author(s):  
Michaela Hoduláková ◽  
Libor Topolář ◽  
Barbara Kucharczyková
Keyword(s):  
Internal Structure ◽  
Experimental Analysis ◽  
Cement Composite ◽  
Early Hydration ◽  
Cement Pastes ◽  
Fine Grained ◽  
University Of Technology ◽  
Mechanical Waves ◽  
Waves Propagation

The aim of this paper is to present results of an experimental analysis focused on the mechanical waves passing through fine-grained materials, prepared from the CEM I 52.5 R Portland cement and the water coefficient w/c = 0.40, during the setting and hardening phase. In the experiment differences in the wave propagation in cement pastes and mortars were investigated. After mixing, both materials were poured into a cylindrical mould with the diameter of 75.0 ± 0.3 mm. These test specimens were then used to observe, in particular, the development of the amplitude of mechanical waves using a measuring setup which was composed for this purpose from the equipment of the Brno University of Technology. The results show that the time of „critical changes" in the internal structure of the material can be determined. These changes are related to the quality of the bonds of the particles in the internal structure which are reflected in the propagation of the mechanical waves within the material. It is also expected that the experimental analysis will help extend the knowledge of mechanical waves propagation in cement-based composite materials during setting.

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