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Tytuł:
Impact of Microphytobenthos Photosynthesis on the Characteristics of the Echo Signal from Baltic Sandy Sediments
Autorzy:
Gorska, N.
Kowalska-Duda, E.
Marszal, J.
Schmidt, J.
Klusek, Z.
Powiązania:
https://bibliotekanauki.pl/articles/177331.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hydroacoustics
backscattering
microphytobenthos photosynthesis
Baltic Sea
Opis:
The understanding the influence of biological processes on the characteristics of the signals backscattered by the sea floor is crucial in the development of the hydroacoustical benthic habitat classification techniques. The impact of the microphytobenthos photosynthesis on the acoustical backscattering properties of the Atlantic sandy sediments was previously demonstrated by Holliday et al. (2004) and Wildman and Huettel (2012). To account for the sensitivity of the hydroacoustical classification techniques to the backscattering properties of local marine sediments, it is important to understand the microphytobenthos photosynthesis impact for the Baltic Sea where the techniques are being actively developed now. This is the main motivation of the paper. In the paper the influence of the microphytobenthos photosynthesis on the characteristics of the echo signals reflected by sandy sediments in the typical Baltic temperature and the salinity conditions is discussed. The interdisciplinary multiday laboratory experiment was conducted to study the impact of benthic microalgal photosynthesis on the characteristics of the echo signal reflected by sandy sediments. Hydroacoustical data were collected under controlled constant light, temperature and salinity conditions. The oxygen content at different levels of the water column was simultaneously monitored.
Źródło:
Archives of Acoustics; 2015, 40, 3; 395-405
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of microphytobenthos photosynthesis on the spectral characteristics of the signal reflected from Baltic sandy sediments
Autorzy:
Jaśniewicz, D.
Gorska, N.
Powiązania:
https://bibliotekanauki.pl/articles/332045.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
backscattering
microphytobenthos photosynthesis
Baltic Sea
Opis:
The use of hydracoustical techniques to classify benthic fauna and flora is one of the important challenges in present marine research. It is crucial to understand the microphytobenthos photosynthesis impact on the backscattering properties of the sea floor in the Baltic Sea, where the techniques are actively developed now. This motivated our study. The data used in the analysis was collected in the multiday laboratory experiment conducted in the frame of the grant of the National Science Centre, Poland (No. N306 773940). In this experiment, during changing light conditions (light/dark photocycles), the hydroacoustical backscattering data was acquired in the aquarium with a sandy bottom. The constant temperature and salinity conditions, typical for the Southern Baltic, were kept, and oxygen content was monitored. In this paper data collected at 280 kHz, was processed. It was studied how the energy of echo and power spectral density of the echo signal, are sensitive to the microphytobenthos photosynthesis.
Źródło:
Hydroacoustics; 2016, 19; 165-171
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An acoustic study of zooplankton diel vertical migration in the Black Sea
Autorzy:
Pezacki, P. D.
Gorska, N.
Soloviev, V.
Powiązania:
https://bibliotekanauki.pl/articles/332185.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
hydroacoustics
backscattering
ADCP
velocity of zooplankton
Opis:
Reliable, rapid and non-invasive techniques are important for the monitoring of the ecosystem of the semi-enclosed Black Sea, especially sensitive to the human impact. Hydroacoustic techniques meet these requirements. In the study, the ADCP data (volume backscattering strength and water velocities), collected in the north-east part of the Black Sea in October 2014, were used to understand some biotic and abiotic processes in the environment. The study was motivated by the fact that the used ADCP mounted on the autonomous (moving vertically) platform provided measurements with significantly higher spatial resolution that it was in the previous hydroacoustical studies of Black Sea ecosystem. The main objective of the analysis was to determine the velocity of zooplankton diel vertical migration and understand the processes responsible for the variability of the volume backscattering strength.
Źródło:
Hydroacoustics; 2017, 20; 139-148
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature detection based on nonparametric statistics of ultrasound echoes
Autorzy:
Byra, M.
Gambin, B.
Powiązania:
https://bibliotekanauki.pl/articles/332315.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
noninvasive temperature monitoring
nonparametric statistics
ultrasound backscattering
Opis:
Different ultrasound echoes properties have been used for the noninvasive temperature monitoring. Temperature variations that occur during heating/cooling process induce changes in a random process of ultrasound backscattering. It was already proved that the probability distribution of the backscattered RF (radio frequency) signals is sensitive to the temperature variations. Contrary to previously used methods which explored models of scattering and involved techniques of fitting histograms to a special probability distribution two more direct measures of changes in statistics are proposed in this paper as temperature markers. They measure the ''distance'' between the probability distributions. The markers are the Kolmogorov Smirnov distance and Kulback-Leiber divergence. The feasibility of using such nonparametric statistics for non- invasive ultrasound temperature estimation is demonstrated on the ultrasounds data collected during series of heating experiments in which the temperature was independently registered by the classical thermometer or thermocouples.
Źródło:
Hydroacoustics; 2015, 18; 17-23
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of a Compton backscattering wall defects detection device using the Monte Carlo method
Autorzy:
Qin, Xuan
Yang, Jianbo
Du, Zhengcong
Xu, Jie
Li, Rui
Li, Hui
Liu, Qi
Powiązania:
https://bibliotekanauki.pl/articles/24202748.pdf
Data publikacji:
2023
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
compton backscattering
Monte Carlo
nondestructive testing
wall defect
Opis:
In view of the shortcomings of traditional wall defect detection methods, such as small detection range, poor accuracy, non-portable device, and so on, a wall defects detection device based on Compton backscattering technology is designed by Monte Carlo method, which is mainly used to detect the size and location information of defects in concrete walls. It mainly consists of two parts, the source container and the detection system: first, through the simulation and analysis of the parameters such as the receiving angle of thebackscattered particles and the rear collimating material of the detector, the influence of the fluorescent X-ray peak of the detector collimating material on the backscattered particle counts is eliminated and the detected error is reduced; second, the ring array detector design, compared with single array detector and surface array detector, can facilitate real-time detection of defect orientation, expanding the single scan range and improving the detection efficiency. After simulation and comparative analysis, the relevant optimal parameters are obtained: the object is detected using a Cs-137 γ-ray source with an activity of 6 mCi, and a ring detector consisting of four 0.5-inch cube-shaped CsI scintillator detectors is placed at 150° to receive the backscattered photons. The simulation analysis using the Monte Carlo FLUKA program showed that the maximum depth of wall defect detection is 8 cm, the maximum error fl uctuation range of defect depth and thickness is ±1 cm, the overall device weight is <20 kg, and the measurement time is <5 min.
Źródło:
Nukleonika; 2023, 68, 2; 57--63
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo calculations of positron implantation profiles and backscattering probabilities in gold
Autorzy:
Aydin, A.
Powiązania:
https://bibliotekanauki.pl/articles/147555.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
backscattering
computer simulation
incoming angle
mean penetration depth
positron
Opis:
The transport of charged particles through matter is worth considering for various applications. In this work, backscattering probabilities and mean penetration depths were calculated from the implantation profiles for positrons of energies 1-75 keV entering normally at various angles into a semi-infinite gold target. The theoretical results of backscattering probability and mean penetration depth are compared with other published [1, 3, 4, 10, 11, 13]. Monte Carlo calculations and experimental results for the semi-infinite gold target. In general, good agreement is observed.
Źródło:
Nukleonika; 2001, 46, 3; 87-90
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo calculations of low energy positrons in silicon
Autorzy:
Aydin, A.
Powiązania:
https://bibliotekanauki.pl/articles/148795.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Monte Carlo method
positron transmission
backscattering
angular distribution
energy distribution
Opis:
Theoretical data for positron scattering from a thin silicon film and semi-infinite silicon are presented as a function of incident and outgoing angles and energies. These theoretical data of the scattering processes of low energy positrons penetrating into silicon were performed by Monte Carlo simulation. The simulation is based on the use of different types of differential cross sections for individual elastic and inelastic scattering i) inelastic scattering; Gryzinski's excitation function to simulate the energy loss and Liljequist's model to calculate the inelastic scattering cross section, ii) elastic scattering; the screened Rutherford differential cross section with the spin-relativistic factor. In calculations on positron traversing matter, it is important to know the transmission through medium, their path lengths, and their energy and angular distribution through matter. The simulation results are well agreed with experiments.
Źródło:
Nukleonika; 2005, 50, 1; 37-42
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrasonic Simulation Research of Two-Dimensional Distribution in Gas-Solid Two-Phase Flow by Backscattering Method
Autorzy:
Fan, Jinhui
Wang, Fei
Powiązania:
https://bibliotekanauki.pl/articles/31339986.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
gas-solid two-phase flow
COMSOL simulation
ultrasonic backscattering method
Opis:
The two-dimensional distribution of gas-solid flow parameters is a great research significance to reflect the actual situation in industry. The commonly used method is the ultrasonic tomography method, in which multiple probes are arranged at various angles, or the measurement device is rotated as that in medicine, but in most industrial situations, it is impossible to install probes at all angles or rotate the measured pipe. The backscattering method, however, uses only one transducer to both transmit and receive signals, and the two-dimensional information is obtained by only rotating the transducer. Ultrasound attenuates greatly in the air, and the attenuation changes with frequency. Therefore, Comsol is used to study the reflection of particles with different radii in the air to ultrasound with various frequencies. It is found that the backscattering equivalent voltage is the largest when the product of ultrasonic frequency and particle radius is about 27.78 Hz·m, and the particle concentration of 30% causes the strongest backscattering. The simulated results are in good agreement with the Faran backscattering model, which can provide references for selecting the appropriate frequency and obtaining the concentration when measuring gas-solid two-phase flow with the ultrasonic backscattering method.
Źródło:
Archives of Acoustics; 2022, 47, 3; 373-382
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameterization of light scattering for solving the inverse problem of determining the concentrations of the principal light scattering and absorbing admixtures in shelf waters
Autorzy:
Pelevin, V.N.
Rostovtseva, V.V.
Powiązania:
https://bibliotekanauki.pl/articles/48226.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
bio-optical modelling
backscattering
sea water
shelf water
light absorption
irradiance
Opis:
A method for estimating the water backscattering coefficient was put forward on the basis of experimental data of diffuse attenuation coefficient for downwelling irradiance and irradiance reflectance. Calculations were carried out for open sea waters of different types and the spectral dependencies were found (‘anomalous’ spectra) and explained. On this basis, a new model of light backscattering on particles in the sea is proposed. This model may be useful for modelling remote sensing reflectance spectra in order to solve the inverse problems of estimating the concentration of natural admixtures in shelf waters.
Źródło:
Oceanologia; 2001, 43, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo simulation of polarization of light back-scattered from randomly rough surfaces
Autorzy:
Jiang, Yuxiang
Li, Zhenhua
Powiązania:
https://bibliotekanauki.pl/articles/2202767.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
backscattering
randomly rough surface
Stokes parameters
Monte Carlo method
polarized light
Opis:
Laser detection devices obtain target information from back-scattered light, such as lidar. The recognition rate can be improved by analyzing intensity and polarization of echo signal. In this paper, Monte Carlo method is used to generate a large number of randomly rough surfaces to simulate targets. Every rough surface is discretized into a large number of micro-surface elements. Stokes parameters of back-scattered light are calculated by numerical integration. Incident light is p-, s-, 45° linearly polarized light and right-hand circularly polarized light, respectively. Numerical results show that when s- and p-linearly polarized light incident on a metal rough surface, back-scattered light appears circularly polarized component. Metal rough surface resembles a wave plate with phase difference, with the fast axis parallel or perpendicular to the 45° direction. When linearly polarized light is incident on dielectric rough surface, back-scattered light has no circularly polarized component. Experimental data are consistent with the numerical results. The above research provides a new basis for laser detection device to identify metal targets from the environmental background.
Źródło:
Optica Applicata; 2023, 53, 1; 65--85
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
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