scholarly journals Reconstruction of Function of Particles Distribution by Sizes with Laser Sensing Method Use

10.12737/6634 ◽  
2014 ◽  
Vol 3 (6) ◽  
pp. 37-42 ◽  
Author(s):  
Половченко ◽  
S. Polovchenko ◽  
Чартий ◽  
Pavel Chartiy
Keyword(s):  
Distribution Function ◽  
Laser Radiation ◽  
Complex Refractive Index ◽  
Optical Parameters ◽  
Normal Distribution Function ◽  
Laser Radiation Intensity ◽  
Gas Cleaning ◽  
Fabric Filter ◽  
Laboratory Setup ◽  
Laser Sensing

A laser sensing inverse task solution method without using of integral equations has been suggested in this paper and it can be used for aerosol particles’ sizes and concentration monitoring equipment creation for the real practice of the industrial production. This method is based on the laser radiation intensity weakening at a limited set of the probing laser radiation wavelengths. The computer simulation of aerosol flow parameters has been fulfilled and its results showed that during the regular operation of enterprise’s dust cleaner equipment at the certain point of the technological process the aerosol can be described by a function of particles distribution by sizes, and this function depends on finite number of parameters. The particles’ sizes distribution function is described by the logarithmic normal law after a fabric filter as a last step of the dust cleaner equipment. The laboratory setup realizing the laser sensing at the several laser radiation wavelengths possibilities simultaneously by the spectral transparency and integral light scattering methods for investigation of studied aerosol flows’ optical parameters dependence has been created. A complex refractive index of the studied substance has been investigated. The dependence between the logarithmic normal distribution function parameters and the average volume - surface diameter values received as a result of the sensing has been revealed. The suggested method of the inverse task solution can be developed for the dust gas cleaning equipment refusals detection.

scholarly journals Retrieval of the tropospheric aerosol microphysical characteristics from the data of multifrequency lidar sensing

2018 ◽  
Vol 176 ◽  
pp. 05055 ◽  
Author(s):  
S. Samoilova ◽  
M. Sviridenkov ◽  
I. Penner ◽  
G. Kokhanenko ◽  
Yu. Balin
Keyword(s):  
Refractive Index ◽  
Distribution Function ◽  
Complex Refractive Index ◽  
Size Distribution Function ◽  
Coarse Fraction ◽  
Optical Parameters ◽  
Raman Lidar ◽  
Tropospheric Aerosol ◽  
Lidar Measurements ◽  
The Vertical Distribution

Regular lidar measurements of the vertical distribution of aerosol optical parameters are carried out in Tomsk (56°N, 85°E) since April, 2011. We present the results of retrieval of microphysical characteristics from the data of measurements by means of Raman lidar in 2013. Section 2 is devoted to the theoretical aspects of retrieving the particle size distribution function U(r) (SDF) assuming a known complex refractive index m (CRI). It is shown that the coarse fraction cannot be retrieved unambiguously. When estimating U(r) and m together (section 3), the retrieved refractive index is non-linearly related to the optical coefficients and the distribution function, which leads to appearance of different, including false values of m. The corresponding U(r) differs only slightly, so the inaccuracy in m does not essentially affect the retrieval of the distribution function.

Technique for measuring laser radiation intensity in biological tissues

2013 ◽  
Vol 2 (3) ◽  
Author(s):  
Pavel Grachev ◽  
Victor Loschenov
Keyword(s):  
Laser Radiation ◽  
Optical Fiber ◽  
Radiation Intensity ◽  
Light Propagation ◽  
Continuous Wave ◽  
Biological Tissues ◽  
Optical Parameters ◽  
Laser Radiation Intensity ◽  
Transmitted Radiation ◽  
Tissue Surface

AbstractLaser methods, such as laser-induced fluorescence diagnostics, photodynamic therapy (PDT), and hyperthermia, are finding increasing use in medicine. Irradiation can be performed both with and without contact on the tissue surface. In the case of contact irradiation, especially when laser radiation is introduced into biological tissue through an optical fiber, it is important to know the processes taking place at the irradiation fiber end. These processes affect diffusely reflected radiation which returns to the fiber. By analyzing backscattered radiation, we can evaluate the quality of the radiation procedure and the state of the fiber end. The objectives of this study were to develop a method and device for measuring backscattered radiation power and using this method, to determine the time and temperature ranges realized in PDT and hyperthermia.Light propagation is discussed in bent optical fibers. A technique is proposed for measuring laser radiation intensity in the optical fiber bend. Based on this technique, a system was developed for monitoring the laser radiation dose absorbed in biological tissues. We studied samples of bovine liver, muscle and brain tissues. Experiments were performed using a 675 nm, 100–2200 mW continuous wave semi-conductor laser. Laser radiation was delivered through a silica/polymer optical fiber. Data concerning the temperature and transmitted radiation intensity was acquired.Modeling of the light propagation in a bent optical fiber showed that the sensitivity of the method depends on the position of the photodetectors, but is independent of the loop number of the optical fiber. The results of experiments are presented using different types of biological tissues. We obtained the experimental dependencies of backward and transmitted radiation intensities and the temperature of the tissue surface in the irradiated region on the irradiation time measured with a flat-end fiber. The characteristic ranges of tissue heating caused by irradiation were determined for use in clinical practice.The optical parameters of biological tissues change with increasing temperature. This affects the intensity of transmitting radiation and diffuse radiation entering the fiber. The change in the backscattered radiation intensity greatly depend on the temperature of the irradiated area. The control of the irradiation of biological objects provides an efficient delivery of laser radiation to biological tissues and increases hyperthermia and PDT treatment effect.

scholarly journals Copulaesque Versions of the Skew-Normal and Skew-Student Distributions

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 815
Author(s):  
Christopher Adcock
Keyword(s):  
Distribution Function ◽  
Normal Distribution ◽  
Degrees Of Freedom ◽  
Special Functions ◽  
Normal Distribution Function ◽  
Skew Normal Distribution ◽  
Marginal Distributions ◽  
Student’S T ◽  
Normal Copula ◽  
Skew Normal

A recent paper presents an extension of the skew-normal distribution which is a copula. Under this model, the standardized marginal distributions are standard normal. The copula itself depends on the familiar skewing construction based on the normal distribution function. This paper is concerned with two topics. First, the paper presents a number of extensions of the skew-normal copula. Notably these include a case in which the standardized marginal distributions are Student’s t, with different degrees of freedom allowed for each margin. In this case the skewing function need not be the distribution function for Student’s t, but can depend on certain of the special functions. Secondly, several multivariate versions of the skew-normal copula model are presented. The paper contains several illustrative examples.

scholarly journals Ground Movement Analysis Based on Stochastic Medium Theory

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Meng Fei ◽  
Wu Li-chun ◽  
Zhang Jia-sheng ◽  
Deng Guo-dong ◽  
Ni Zhi-hui
Keyword(s):  
Distribution Function ◽  
Back Analysis ◽  
Movement Analysis ◽  
Measured Data ◽  
Ground Movement ◽  
Pile Driving ◽  
Normal Distribution Function ◽  
Stochastic Medium ◽  
Medium Theory ◽  
Vertical Ground

In order to calculate the ground movement induced by displacement piles driven into horizontal layered strata, an axisymmetric model was built and then the vertical and horizontal ground movement functions were deduced using stochastic medium theory. Results show that the vertical ground movement obeys normal distribution function, while the horizontal ground movement is an exponential function. Utilizing field measured data, parameters of these functions can be obtained by back analysis, and an example was employed to verify this model. Result shows that stochastic medium theory is suitable for calculating the ground movement in pile driving, and there is no need to consider the constitutive model of soil or contact between pile and soil. This method is applicable in practice.

scholarly journals Sputtering of Neutral Molecules and Molecular Ions From the Adenine Crystal Surface Induced by the UV Picosecond Laser Pulse

1982 ◽  
Vol 1 (1) ◽  
pp. 37-43 ◽  
Author(s):  
V. S. Antonov ◽  
V. S. Letokhov ◽  
Yu. A. Matveyets ◽  
A. N. Shibanov
Keyword(s):  
Laser Radiation ◽  
Kinetic Energy ◽  
Crystal Surface ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Molecular Ions ◽  
Laser Radiation Intensity ◽  
Ion Sputtering ◽  
Absorbed Energy ◽  
Picosecond Laser Pulse

This paper presents the results of observation of sputtering of neutral molecules and ions from the crystal adenine surface induced by fourth-harmonic Nd:YAG laser radiation with a pulse duration of 30 ps. The energy fluence of laser pulses was in the region (1–3) × 10−4 J/cm2. The kinetic energy distribution of the sputtered molecules spreads up to 0.7 eV. The experiment shows that the threshold of adenine molecular ion sputtering is connected with absorbed energy density in upper layers of the crystal surface but not by laser radiation intensity.

PrekotAC as Filter Aids for Efficient Dust Separation in a Fabric Filter

2014 ◽  
Vol 67 (4) ◽  
Author(s):  
S. Hajar ◽  
M. Rashid ◽  
A. Nurnadia ◽  
H. Norelyza ◽  
M. Ammar
Keyword(s):  
High Efficiency ◽  
Size Fraction ◽  
Inert Material ◽  
Air Pollution Control ◽  
Gaseous Emissions ◽  
Gas Cleaning ◽  
Fabric Filter ◽  
Wear And Tear ◽  
Gaseous Stream ◽  
Filter Aids

Fabric filters are extensively used as an air pollution control system for its high efficiency to collect particles from gaseous stream. The system is commonly installed in many incineration plants as the means to control dust and gaseous emissions. Unfortunately, their applications in these facilities are short lived due to wear and tear of the fabric media. This is because the fabric filter is not adequately conditioned before it is put up into service. A simple technique is to apply so called ‘pre-coat’ material to coat a layer of inert material onto the surface of the fabric as a ‘barrier’ for protection as well as to allow a uniform air flow passing through the filter media. In this regard, a newly formulated filter aids material known as PrekotAC, not merely acts as an adsorbent for flue gas cleaning but also an efficient dust separation agent in a fabric filter system. A mixture of PreKotTM:Activated Carbon of 40:60 (%weight) was found to be the most preferable combination with its particle size distribution between 75 and 600μm, which is bigger size fraction than the original materials.

scholarly journals Фотоиндуцированная обратимая локальная деформация рельефа поверхности в объемных монокристаллах TlInSe-=SUB=-2-=/SUB=-, TlGaTe-=SUB=-2-=/SUB=- и TlSe

2018 ◽  
Vol 44 (14) ◽  
pp. 86
Author(s):  
Y.G. Shim ◽  
T. Asahi ◽  
K. Wakita ◽  
Н.Т. Мамедов ◽  
Е.Н. Алиева ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Room Temperature ◽  
Surface Deformation ◽  
Damage Threshold ◽  
Spot Size ◽  
Photon Absorption ◽  
Laser Radiation Intensity ◽  
Laser Spot Size ◽  
Absorption Length ◽  
Bulk Single Crystals

AbstractGiant macroscopic expansion of the surface relief, localized within a laser spot size, has been observed in bulk single crystals of TlInSe_2, TlGaTe_2, and TlSe at room temperature and laser radiation densities lower by at least two orders of magnitude than the material optical damage threshold. Quantitative estimations of the deformation magnitude in this local region were obtained using an interference dilatometer. The photon absorption length was determined with the aid of spectroscopic ellipsometry. It is established that the surface deformation amounts to 2.6 × 10^–3 at a laser radiation intensity of 19 mW/mm^2. The observed phenomenon has a thermal nature and is probably related to a low thermal conductivity of the materials studied.

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