scholarly journals Оценка усталостных повреждений в органическом стекле оптическими методами

2019 ◽  
Vol 127 (11) ◽  
pp. 870
Author(s):  
А.П. Владимиров ◽  
И.С. Каманцев ◽  
Н.А. Друкаренко ◽  
В.Н. Тришин ◽  
Л.А. Акашев ◽  
...  
Keyword(s):  
Refractive Index ◽  
Irreversible Processes ◽  
Material Density ◽  
Small Areas ◽  
Testing Tools ◽  
Order Of Magnitude ◽  
Tools And Techniques ◽  
Optical Paths ◽  
Relative Change ◽  
Limiting Values

Abstract On the basis of fragments of time-averaged speckle images registered with no stopping of cyclic loading, the features of nucleation, onset, and propagation of a crack in the bulk of a transparent prismatic sample with a sharp V-shaped notch have been found. It has been shown that the first signs of fatigue damage occur not at the top of the notch, but at a distance of 400 μm from it in the sample center within an area with a diameter of 200 μm. After the beginning of the development (“onset”) of the crack, the size of the zone of irreversible processes exhibits an increase by an order of magnitude. The distribution of the refractive index and the density around the crack has been studied based on changing speckle images and with the use of ellipsometry. It has been shown that the maximum value of relative change in density being at least 2 × 10^–3, is located near the crack. The speckle method can serve a basis for the development of nondestructive testing tools and techniques that make it possible to assess the time preceding crack onset according to the changing rate and the limiting values of the refractive index and material density, as well as according to other parameters affecting the change in the optical paths of waves within small areas about 10 μm in size.

Strong Exciton Polariton Dispersion in Multimode GaN Microcavity

2009 ◽  
Vol 1182 ◽  
Author(s):  
Mei-Chun Liu ◽  
Yuh-Jen Cheng ◽  
Shih-Hsin Hsu ◽  
Hao-Chung Kuo ◽  
Tien-Chang Lu ◽  
...  
Keyword(s):  
Refractive Index ◽  
Experimental Observation ◽  
Interaction Constant ◽  
Axial Mode ◽  
Photon Interaction ◽  
Frequency Spacing ◽  
Order Of Magnitude ◽  
Pl Spectrum

AbstractWe report the experimental observation of a very strong cavity polariton dispersion in a multi-axial mode GaN microcavity. The linewidth of photoluminescent (PL) spectrum covers a few cavity axial modes. The resonant photoluminescent peaks have a strong dispersion. The frequency spacing between adjacent peaks decreases by almost a factor of five from 470nm to 370nm. The strong dispersion can be well described by cavity polariton dispersion, but not by the dispersion of the refractive index of GaN. The measured exciton-photon interaction constant is 260 meV. It is an order of magnitude higher than the typically reported values for GaN microcavities

scholarly journals Crystal Growth and Solute Trapping

1983 ◽  
Vol 23 ◽  
Author(s):  
Michael J. Aziz
Keyword(s):  
Free Energy ◽  
Steady State ◽  
Laser Annealing ◽  
Solute Drag ◽  
Irreversible Processes ◽  
Maximum Speed ◽  
Growth Speed ◽  
Solute Trapping ◽  
Order Of Magnitude ◽  
Energy Dissipated

ABSTRACTA simple model for solute trapping during rapid solidification is presented in terms of a single unknown parameter, the interfacial diffusivity Di. A transition from equilibrium segregation to complete solute trapping occurs over roughly an order of magnitude in growth speed, as the interface speed surpasses the maximum speed with which solute atoms can diffuse across the interface to remain ahead of the growing crystal. This diffusive speed is given by Di/λ, where λ is the interatomic spacing, and is typically of the order 10 meters per second. Comparison is made with experiment. The steady–state speed of a planar interface is predicted by calculating the free energy dissipated by irreversible processes at the interface and equating it to the available driving free energy. A solute drag term and an intrinsic interfacial mobility term are included in the dissipation calculations. Steady–state solutions are presented for Bi–doped Si during pulsed laser annealing.

Tools and Techniques for Model Based Testing

2010 ◽  
pp. 226-249
Author(s):  
Swapan Bhattacharya ◽  
Ananya Kanjilal ◽  
Sabnam Sengupta
Keyword(s):  
Software Development ◽  
Development Time ◽  
Domain Model ◽  
Test Case Generation ◽  
Test Case ◽  
Model Based ◽  
Testing Tools ◽  
Research Activities ◽  
Model Based Testing ◽  
Tools And Techniques

Software testing has gained immense importance in the present competitive world of developing software more quickly, more efficiently and more accurately. Testing activity is carried out throughout the lifecycle of software development and not only towards the end of development. Time and effort required to correct errors, detected later is much more compared to those, which are detected earlier. This has direct impact on costs and has led to a splurge of research activities in this domain. Model-based testing has recently gained attention with the popularization of modeling itself. It refers to testing and test case generation based on a model that describes the behavior of the system. The OMG initiative MDA has revolutionized the way models would be used for software development. There are a number of modeling techniques in use today- some have formal syntax like Z, VDM while some are semi-formal like UML. We have made a comprehensive summary of a considerable number of research works on Model Based testing. First, the issues, challenges and problems of model based testing have been discussed. Then the different methods developed for testing or test case generation based on the models are summarized. Finally a list of model based testing tools used for testing has been collectively presented.

Discrete Event Simulation Process Validation, Verification, and Testing

2007 ◽  
pp. 177-212 ◽  
Author(s):  
Evon M. O. Abu-Taieh ◽  
Asim Abdel Rahman El Sheikh
Keyword(s):  
Discrete Event Simulation ◽  
Objective Assessment ◽  
Discrete Event ◽  
Validation And Verification ◽  
Event Simulation ◽  
Testing Tools ◽  
Testing Techniques ◽  
Engineering Practices ◽  
Tools And Techniques ◽  
Simulation Systems

This chapter introduces validation, verification, and testing tools and techniques pertaining to discrete event simulation. The chapter distinguishes between validation and verification within the context of discrete event simulation. Then, we will show the importance of such topic by revealing the amount research done in simulation validation and verification. The chapter subsequently discusses the reasons why simulation projects fail and the sources of simulation inaccuracies. Next, the chapter gives different taxonomies for validation, verification, and testing techniques (VV&T) for both types of simulation systems: object-oriented-based and algorithmic-based. Therefore, the chapter will present a translation of thirteen software-engineering practices suggested for simulation projects. Notwithstanding the significance of providing an objective assessment platform, as such, the chapter will shed light on the independence of VV&T pertaining to simulation systems.

Simulation of imperfections in plastic lenses – transferring local refractive index changes into surface shape modifications

2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Josep Arasa ◽  
Carles Pizarro ◽  
Patricia Blanco
Keyword(s):  
Refractive Index ◽  
Optical Quality ◽  
Density Fluctuations ◽  
Surface Shape ◽  
Free Form ◽  
Optical Simulation ◽  
Material Density ◽  
Local Index ◽  
Index Changes ◽  
Local Refractive Index

AbstractInjection molded plastic lenses have continuously improved their performance regarding optical quality and nowadays are as usual as glass lenses in image forming devices. However, during the manufacturing process unavoidable fluctuations in material density occur, resulting in local changes in the distribution of refractive index, which degrade the imaging properties of the polymer lens. Such material density fluctuations correlate to phase delays, which opens a path for their mapping. However, it is difficult to transfer the measured variations in refractive index into conventional optical simulation tool. Thus, we propose a method to convert the local variations in refractive index into local changes of one surface of the lens, which can then be described as a free-form surface, easy to introduce in conventional simulation tools. The proposed method was tested on a commercial gradient index (GRIN) lens for a set of six different object positions, using the MTF sagittal and tangential cuts to compare the differences between the real lens and a lens with homogenous refractive index, and the last surface converted into a free-form shape containing the internal refractive index changes. The same procedure was used to reproduce the local refractive index changes of an injected plastic lens with local index changes measured using an in-house built polariscopic arrangement, showing the capability of the method to provide successful results.

The Oil Resistance of Rubber. II. Molecular Polarization and Dipole Moment of Purified Natural Rubber

1936 ◽  
Vol 9 (2) ◽  
pp. 296-300
Author(s):  
Shû Kambara
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Dipole Moment ◽  
Natural Rubber ◽  
Dipole Moments ◽  
Molecular State ◽  
True Value ◽  
Order Of Magnitude ◽  
Ether Solution ◽  
Constant Refractive Index

Abstract Natural rubber was purified by Pummerer's method and was dissolved in benzene and ether. The dielectric constant, refractive index, density, and concentration of the solutions were determined. From these data, the molecular polarization and dipole moment were calculated on the assumption that the rubber was dissolved in a molecular state of (C5H8)8. The dipole moments of total and gel rubber were found to be 2.45 and 2.91 × 10−18, respectively. These values are of the same order of magnitude as those of masticated crude rubber obtained by Ostwald. It may be said that the impurities of rubber are interlocked mechanically on the rubber molecule and are not combined chemically. Sol rubber in ether solution shows a far lower value than the values of total and gel rubber. These latter values may be influenced by autoöxidation, and the true value of the rubber hydrocarbon may be far smaller than the result described in this paper.

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