Laser scattering, optical constants and connection to other material performances (Kerr constant, mobility/diffusion coefficient/electrophoresis and depolarization)

Scattering of optical photons from the view of parallel methods related to absorption, scattering, fluorescence, reflection with inclusion of the polarization states of laser beams from experiment and theory give many possibilities for obtaining indirect data on material, processes, and dynamics. As a method with minimal perturbations, if low power beams are involved, certain type of data is provided. In fundamental dependences of various material properties, many phenomenological and basic laws are covered. Several coupled variables, primarily with the processes of scattering, pointing out further possibilities for linking the obtained theoretical or experimental results were presented. By including simulations, this associates with biological environments / variables for properties equivalent to defined tissues, cells, and characteristics. Along with selected formalisms including Stokes vectors and scattering matrices, a biological cell as an object can be monitored in time and influence of various environments could be predicted. Connecting Kerr’s effect with depolarization and scattering makes the complete description of molecule possible. Angular scattering observation with experimental possibilities gives the fastest practical data. This enables interpretation of E. coli with the application of Stokes vector formalisms. A relatively small number of material constants for many simulation cases could give draft estimation, but the experiment depends on the measuring devices and samples. The necessary symmetries showing the size of the scattering centers are analyzed, with the scattering data for some liquids (known / less known). From measured data, depolarization could be calculated, and with refractive index (molar refraction) connection with Kerr effect/ birefringence for selected solutions and behavior of molecules could be monitored. From the experimental Rayleigh factors, cross section (apparent/ effective) and attenuation coefficients for pure liquids were calculated. An approach for the correct assessment of the measurement uncertainty in the process of calibration of polyethylene samples. Keywords: Scattering, laser, Kerr effect, depolarization, bacteria, Mieplo

REMOVAL OF THE FALSE TARGETS IN THE ISSUESOF SPATIAL TRIANGULATION BY PROJECTIVE GEOMETRY METHODS

This paper deals with an issue of determination of the spatial coordinates within confined area in general terms. Mobile air space control stations were set and related to the system of spa- tial triangulation. As a result of the air space "scanning", targets appear in adequate representa- tion, representing identified aircrafts and other flying objects (FOs). The main objective is inter- pretation of collected data processing, in order to determine the reliable coordinates of an air- craft. The problem of false target identification occurs when data are analyzed from only two sta- tions. Descriptive Geometry method, for the construction of the planes containing rays targeted from the station towards the flying objects, in both classic-orthogonal projections and 3D model, as well, offers the solution of a problem. Dynamic 3D model consists of two flying objects, moni- tored from two stations in predefined time periods. The constructive 3D solutions represent geo- metrical locus of false targets trajectories, for several settings of flaying objects and monitoring stations. The analyses have shown geometrical positioning of the third station impact to the exact FO's coordinates determination. The geometrical solution could be the key for the development of numerical method, which will lead to applied software solutio

Gamma Irradiation Effects in Optical Fibres, Splitters, and Connectors

The paper presents a brief overview of contemporary ELION techniques with stress on their use for material modification and dosimetry. In the attempt to avoid some common misjudges of irradiation effects, special attention is paid to exact definition of irradiation geometry and careful adjustment of dose rates, which enable a proper elaboration of experimental results. In particular, effects of gamma-rays irradiation on properties of commercial optical fibres, splitters, connectors, and fibre joints are examined, which enables monitoring of irradiation effects in complex configurations made of materials with different radiation hardness (resistance). It has been established that gamma-rays irradiation of the investigated elements influences, in different ways, the transmission of laser beam signals of various wavelengths, under different modulation regimes. After irradiation, the signal attenuation is noticeably larger, both in optical connectors and optical splitter, than before it, and the effect increases in time. The effects are more pronounced at the 99 % than at the 1 % Y-splitter output at both measured wavelengths, and are more pronounced at 1310 nm than at 1550 nm

THE FIRST AIRCRAFT FACTORY IN SERBIA

THE FIRST AIRCRAFT FACTORY IN SERBIA, Proceedings of Selected Papers and Abstracts of The Third International Students’ Scientific Conference "MULTIDISCIPLINARY APPROACH TO CONTEMPORARY RESEARCH - Cultural and Industrial Heritage

Interaction of ruby laser with carbon fibrous materials

Carbon fibrous materials are interesting because of their good properties and numerous possible applications. The characteristics of these materials can be programmed by careful selection of the modification process parameters. The laser technique can be successfully employed for these purposes. The high temperatures arising in the material during a short laser pulse can cause a number of changes in the material. Carbon fibrous materials with different textile shapes, during different stages of processing, were exposed to laser radiation. A ruby laser (lambda=694.3 nm) was used to modify the material. The structural changes were examined by scanning electron microscopy and Xray diffraction. It way established that the radiation of this laser induces structural changes leading to a better arrangement of the turbostratic carbon fiber structure.5th Young Researchers Seminar, Dec 25-26, 2006, Belgrade, Serbi

Influence of Nd3+: YAG laser irradiation on the properties of composites with carbon fibers

The carbon fiber based composites: carbon fiber reinforced plastic and 3D carbon fiber reinforced carbon composites were exposed to the Nd3+: YAG laser beams (1064 nm). Experimental parameters for the interaction of the laser beam with 1.5 Hz pulse frequency and with pulse duration 0.7 ms varied: energy density between 128 and 1915 J cm(-2), pulse energy from 1 to 3 J and mean power in the range between 0.4 and 6.5 kW. Apparently, the energy absorbed by the composite samples was mainly converted into thermal energy, causing a range of damages, from instantaneous evaporation to cracking and melting, which resulted in a crater-like damage. Program ImageJ was executed for quantitative analysis of generated damages based on micrographs obtained by SEM and light microscopes. Obtaied results enable identification of the laser induced changes in the material. (C) 2017 Elsevier Ltd. All rights reserved

Interaction of laser beams with carbon textile materials

Purpose - The purpose of this paper is to present the results of interaction occurring during the exposition of some specific carbon textile materials obtained in laboratory conditions to beams of various laser types. Design/methodology/approach - Carbon fabric materials - fiber, felt and cloth - obtained from different precursor materials and prepared at various process conditions (oxidized, partially carbonized, carbonized, graphitized), were exposed to pulses of various lasers (Nd3+:YAG, alexandrite, ruby). Findings - Depending on the laser power, plasma and destructive phenomena occurred. In the case of an interaction between a Nd3+: YAG laser beam and specimens of thickness in millimeter range, the authors have estimated the threshold of the energy density for drilling and discussed the possible models of the interaction. Research limitations/implications - The results have implications in the estimations of quality as well as in the improvement of material processing, giving some new light to the changes of mechanical and optical constants of the material, as well as to the changes of carbon groups of the material, which would be useful for different types of modeling. Future research will be in the interaction of laser beams with various textile materials, where the investigation would cover the microstructure changes and the implications on cloth cutting and welding, concerning the damages as well as relief structures, specially renew for fs laser regimes. Originality/value - The area of laser applications in the textile industry is supported by scientific and applicative exploration. However, fewer results are concerned with deep introspection into the microstructure of the damages considering the laser interaction with carbon fiber and other carbon-based textiles