Lidar, as an important tool for studying atmospheric aerosol, is widely used in studying the distribution of atmospheric aerosol pollution. In environmental monitoring, especially when using mobile lidar for measurements, it's important to know not only situations of the pollution, but also the coordinates of their sources, and their dynamics distribution. The article introduces a method for calculating the coordinates of the objects locations according to the coordinates of the lidar, the detection direction and the distance between the lidar to the objects. Finally, the programming implementation of the method and its application in the development of auxiliary lidar systems.
This work presents the model calculations of the radiation attenuation of the lidars used to diagnose gas-aerosol pollution in the atmosphere in the range from UV to mid-IR. The contributions of the main atmospheric gases (vapor of H2O, CO2, O3) as well as a number of industrial gases for the spectral ranges of the most prominent gas-aerosol impurities in the atmosphere for remote sensing using NIR and LWIR-lidars, are taken into account.
Lidar, as an important tool for studying atmospheric aerosol, is widely used in studying the distribution of atmospheric aerosol pollution. In environmental monitoring, especially when using mobile lidar for measurements, it's important to know not only situations of the pollution, but also the coordinates of their sources, and their dynamics distribution . The article introduces a method for calculating the coordinates of the objects locations according to the coordinates of the lidar, the detection direction and the distance between the lidar to the objects. Finally, the programming implementation of the method and its application in the development of auxiliary lidar systems.
The current level of technical development has led to increased number of anthropogenic hazards including emissions from industrial and agricultural enterprises, terrorist threats using chemical and organic components etc. An important factor in ensuring safety is the timely detection, identification, and localization of sources of danger. In this regard, remote methods, including laser ones, become more and more important allowing detecting and identifying danger in real time and at a distance from its source. The paper presents a calculation of the laser radiation absorption by water vapor for the wavelengths of CO2-laser generation lines. It is shown that absorption caused by H2O, C2H4 and NH3 at some laser generation lines can significantly affects the results of remote detection of organic components depending on the concentration of these gases in the atmosphere. These results can be useful for specialists that develop instruments and methods for remote detection of organic compounds in the atmosphere.
The report discusses the possibility of studying aerosol pollutions over an urban area, including plumes from local sources, using scanning lidar systems. The main task is to reproduce the spatial structure of aerosol plumes and compare it with the topographic map of the city - 3D mapping. As an example of scanning aerosol emissions in the horizon plane, the results of observing the dynamics of the aerosol field over Tomsk, obtained by the LOSA-M3 lidar, are given.
A possibility of monitoring of the operating mode of the plasma emitter of electrons of a pulsed accelerator (300 keV, 0.5 μs) is considered on the basis of the analysis of the visible radiation spectrum in the region of the accelerating gap. The spectrum was recorded using the optical system of a complex diagnostic device for controlling the parameters of the vacuum diode of the accelerator and spectrometer, the optical probe of which is mounted opposite the accelerating gap and is protected from the direct action of an electron beam. Characteristic visible spectra were recorded in the region of the accelerating gap for cathodes made of common structural materials (copper, graphite, and stainless steel), which makes it possible to distinguish between the electron beam generation mode and vacuum gap short-circuiting mode.
In this work, photodetectors with a built-in cooling system based on Peltier elements and with a cooling system based on a Dewar flask filled with liquid nitrogen are experimentally studied with the aim of practical estimation and comparison of capabilities of the photodetectors with different photosensitive element cooling types.
Substances with different absorption spectra have different backscatter spectra. If the range of sounding wavelengths is narrow, but includes evident absorption bands of an aerosol substance, then this substance can be detected from the backscattering spectrum. This is a ground for the use of the differential scattering (DICS) technique for the detection of known organic compounds in natural and anthropogenic aerosol. CO2 lasers with the wavelength tuning range 9–11 μm, which includes the absorption bands of many organic substances, are apparently the most suitable for DICS implementation. It should be borne in mind that when the imaginary part of the refractive index changes (for example, when an absorbing substance is added to a water drop), the real part of the refractive index is also changes. For large particles (r ≥ 10 μm), even small changes in the refractive index significantly affect the backscattering efficiency. The accuracy of the literature data is insufficient for preliminary (a priori) calculation of aerosol backscatter coefficients. Therefore, the development of DICS requires extensive field measurements and their complex mathematical processing with the use of machine learning algorithms. This research sets out the task of systematization of the backscattering radiation by atmospheric aerosol with different organic substances and finding out the wave lengths where the backscatter signal is higher than the selective and continuum atmospheric molecular absorption.
The report discusses the results of experiments on the registration of backscattering of IR radiation from various aerosol formations. The studies were conducted on the bench for prototyping lidar measurements at a controlled route. Water and solutions in water of tryptophan, salt, alcohol, glycerin, and reduced nicotinamide adenine dinucleotide (NADH) served as model media. For the experiments, the stand was upgraded with an IR radiation source – a tunable waveguide CO2 laser, and an IR receiver – cooled with liquid nitrogen MCT. As a result of the experiments, the ability to discriminate a number of aerosols among themselves by changes in the absorption spectrum during laser wavelength tuning along the lines of a CO2 laser, which can be used in remote laser sensing, was determined.
Experiments were carried out on model objects to study the fluorescence and Raman spectra, simulating the presence of heavy hydrocarbons in various concentrations. The use of several sensing wavelengths and a wide spectrum of recording wavelengths potentially makes it possible to identify the yield of such hydrocarbons, which create a concentration of saturated vapors of 0.02-10 ppm at a temperature of 20± 5 °С.
The paper considers the possibility of determining the material of the object that caused damage to the turbine blade of the aircraft by optical methods with minimal impact on the blade. Experimental studies of the registration of emission spectra of residual quantities of duralumin and iron on a titanium substrate are presented. It is shown that the emission lines of these substances can be distinguished against the background of the substrate spectrum.
In the report the results of experiments on the registration of IR radiation backscattering from organic aerosol are presented and discussed. The studies were conducted on the bench for prototyping lidar measurements at a controlled optical way. Water aerosol and water aerosol containing organic components like tryptophan, alcohol, glycerin, and reduced nicotinamide adenine dinucleotide (NADH) served as model media. For these experiments we have modified the experimental set up under replacing UV laser on IR one -- a tunable waveguide CO2- laser. The IR photodetector MCT cooled by liquid nitrogen was used. As a result of the study, the ability to discriminate a number of aerosols among themselves by difference of the absorption spectra under CO2- laser wavelength tuning was demonstrated. It can be used in remote sensing of the different types of organic aerosols.
The paper describes a developed sample of a mobile (helicopter) laser spectroscopic system, provides diagrams, and presents discussion of the results of experimental studies of fluorescence and Raman spectra of model objects, simulating the presence of heavy hydrocarbons in various concentrations.
Currently, there is a widespread occurrence of breast cancer. Long-term radical mastectomy can lead to the development of lymphedema. Finding intraoperatively unaffected lymph nodes, and therefore their preservation, could prevent the development of lymphedema. The authors describe the hardware of the device of extended photodynamic visualization for differentiation of the lymphatic pathways of closely located organs. This devices allows to work with two dyes (methylene blue and indocyanine green) at once. The article also presents studies proving the efficiency of the methodology.
This paper offers a hardware programming method to automatically collect,process,transmit and store the meteorological data and data of geopositioning on the basis of the ATmega microcontroller and soft hardware Arduino when logging LIDAR measurements and further application of the data obtained in the processing LIDAR measurements.
Measurements of the diffuse reflection coefficients of organic and inorganic materials and media in solid, granular and liquid forms were made in the UV field of 230-400 nm. A single channel spectrometer with an integrating sphere was used. Relation between diffuse reflection coefficients and the structure and composition of the samples is discussed. These data allow us to estimate the prospect of machine vision systems application for the UV range in such areas as biology, geology, remote control of materials and media.
In the paper a simple spectral unit designed for excitation and registration of luminescence spectra of natural objects is described. The unit is composed of two basic systems: an excitation system and a registration system. Either x-ray or laser emission can be used for luminescence excitation. The registration system is based on lattice monochromator. The studied object is placed directly at the monochromator entrance slit. Two lead plates are located inside the monochromator case. They protect photodetector that is located behind the monochromator exit slit from x-ray radiation. When emission is decomposed by the diffraction grating, spectrum aliasing occurs, which can be eliminated using optical filters. The diffraction grating rotation is controlled by a computer. Manual control of the rotation angle is also provided. The PMT signal, amplified by dc amplifier, goes to analog-digital converter (ADC). Digitized ADC signal goes to COM port of the computer. Spectrum projection is displayed on the screen and can be recorded to computer’s memory. Switching of analog devises to the dc amplifier output is provided. Examples of processing of the experimental results, obtained using the abovementioned unit, are presented in the paper.
The task that faced the authors was construction of a mobile lidar complex for detection and investigation of aerosol-gas formations in the atmosphere. The complex must be constructed of commercial industrially produced components as much as possible. Many of engineering solutions had been previously worked out by the authors when the first lidar of such type was developed. The complex is designed for study of capabilities of lidar sensing for remote investigation of aerosol-gas formations by their fluorescence and Raman scattering spectra, as well as topographyc objects by fluorescence spectra of their surfaces. The complex has been tested in 2016, and may be applied for atmospheric sensing, for detection of potentially hazardous and dangerous admixtures above the cities, industrial and agricultural emissions, including emissions after disclosures of agricultural animal burial sites. The complex is mounted on a motor vehicle chassis and is energy-independent, and that allow using it for remote sensing of different objects in different natural conditions. Probing distance: 30 000 meters in elastic scattering channel and 5 000 meters in fluorescence channel.
KEYWORDS: LIDAR, LabVIEW, Control systems, Cameras, Computer programming, Human-machine interfaces, Atmospheric optics, Surveillance, Digital video recorders, Video surveillance
Integrated automation software for remote lidar complex is developed within this work. The complexity of software is caused by the presence of the remote controls and measurement units in the lidar complex structure. This task is solved by the unification of all these devices into a single program for improving the efficiency of the operator and the lidar system as a whole. The software is fulfilled using LabView 2014 programming environment, it functionally contains a number of executable units for every element of the system.
Processes of inversion creation in a number of barium and europium atomic transitions under pumping of vapors by eximer XeCl* and KrF* lasers have been investigated. Qualitative study of inversion creation mechanisms that are common for barium and europium atoms has been carried out. Necessary conditions for observation of atom lines of Ba and Eu amplified spontaneous emission (ASE) have been formulated. It has been found that observed absence of long-wave satellites of Eu resonant lines is caused by ASE absence in atomic transitions 8p8P9/2 → 6d8D07/2 and 8p8P9/2 → 6d8D011/2 of europium atom. Whereas, absence of ASE in transitions 8p8P9/2 → 6d8D07/2 and 8p8P9/2 → 6d8D011/2 of Eu atom is a result of high offset, or starting of pre-dissociating pumping channel of 6d8D07/2,11/2 Eu levels. Problems, caused by of undetermined nature of resonant emission that is observed under optical pumping of europium and barium vapor, are discussed in this paper.
Measurements of the diffuse reflection coefficients of organic and inorganic materials and media in solid, granular and liquid forms were made in the UV field of 230–400 nm. A single channel spectrometer with an integrating sphere was used. Relation between diffuse reflection coefficients and the structure and composition of the samples is discussed. These data allow us to estimate the prospect of machine vision systems application for the UV range in such areas as biology, geology, remote control of materials and media.
At the recent years, the increasing interest to laser methods of detection of harmful and dangerous admixtures in the open atmosphere is observed. In this work, experimental results are given of remote detection of acetone vapors, which is the marker of triacetone triperoxide (TATP), with the use of the frequency-pulse 13С16О2 laser with generation line at 11.2 μm.
In the paper we describe the results of the observation of the aerosol and water droplets formation in binary mixtures of saturated water vapor with air and molecular gases. The kinetics of aerosol particles and droplets generation was studied under electron beam influence on the gas mixtures and without it. The experimental setup includes two gas chambers of 43m3 and 1.5m3 connected through the gas valve. The water vapor supersaturation was gained through the pressure fault from the small chamber to the big one. A portable pulse accelerator of electrons with the energy of electron beam 80 KeV was used for ionization of the gas mixture.
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