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Novel Poly(esterimide)s Containing a Push-Pull Type Azobenzene Moiety-Synthesis, Characterization and Optical Properties
No full textabstractEN: In this paper, novel poly(esterimide)s with attached as a side group azobenzene chromophores are presented. The polymers differing in substituents on the azobenzene moieties and chromophore concentration. Azopolymers were obtained by a two-step synthetic approach. This include the preparation of a precursor poly(esterimide) with benzene moiety pendant from main chains, followed by the covalent bonding of the NLO chromophores onto the polyimide backbone by a post-azo-coupling reaction using the following coupling components: p-nitroaniline, 2-cyan-4-nitroanilin, 2,4-dinitroaniline and Disperse Orange 3. The precursor poly(esterimide) was obtained from synthesized 2,2′[N-phenylethyloaniline-di(4-estro-1,2-dicarboxylic)]anhydride and 4,4′-methylene bis(2,6-dimethylaniline). The degree of functionalization of the poly(esterimide)s was estimated by UV-vis spectroscopy. The obtained polymers were characterized and evaluated by FT-IR, 1H NMR, X-ray, UV-vis, DSC and TGA. The results showed the azopolymers exhibited high glass transition temperatures (Tg=159–224 °C), high thermal stability with decomposition temperatures in the range of 311–334 °C and good solubilities in common organic solvents. First time two-photon absorption (TPA) coefficient in cast films of amorphous azopoly(esterimide)s was measured using Z-scan experiment which was performed with femtosecond laser pulses 100 fs at 800 nm. The TPA coefficient was determined to be in the range of 1.54–11.69cm/GW.score: 25collation: 813-82
Growth and structural properties of thick GaN layers obtained by sublimation sandwich method
No full textabstractEN: The synthesis and characterization of GaN thick layers are reported in this paper. The layers were prepared by sublimation sandwich method (SSM). Powder of GaN was used as the source of gallium and ammonia was used as the source of nitrogen. Sapphire with 3 μm GaN thin film grown by MOCVD was used as the substrate. The GaN layers having a current maximum size of 200 μm thickness and 10 mm×10 mm area were obtained. It is also shown that the crystals of best crystalline quality are obtained with a growth rate of 20 μm/h. Characterization of the layers was performed using rocking curve, maps of reflection, structure refinement and SIMS. Quality of the material is good.score: 25collation: 395-39
Hybrid RANS/LES computation of plane impinging jet flow
No full textabstractEN: Bimonthly Journal, published by IPPT PANscore: 20collation: 117 – 13
Application of test reactions to study micromixing in the rotor-stator mixer (test reactions for rotor-stator mixer)
No full textabstractEN: Rotor-stator devices are known from their ability to generate very high shear stresses; due to focused delivery of energy, their energetic efficiency is regarded as high. In the present work performance of the Silverson double screen 150/250MS inline rotor-stator mixer is investigated using multiple test reactions (a simultaneous diazo coupling between 1- and 2-naphtols and diazotized sulphanilic acid), power measurements and CFD. In experiments a premixture of 1- and 2-naphtols was fed into the system through the main inlet whereas second reagent was introduced through the separate feeding tube. Experiments were carried out for the total volumetric flow rate equal to 0.1 dm3 s−1, the volume ratio of reactant solutions equal to 15, and for the rotor speed from the range between 500 and 9000 rpm. The hydrodynamics, mixing and the course of chemical reactions in the rotor-stator mixer are simulated using the standard k–ε model of Ansys Fluent and the multi-reference frame approach. The presented model is able to properly predict the power input to the rotor-stator system and details of turbulence structure, which was confirmed by comparing experimental data with model predictions for power input and product distributions.score: 40collation: 172-17
Dynamics of dust explosions suppression by means of extinguishing powder in various industrial conditions
No full textabstractEN: In industrial conditions, there are different kinds of installations endangered by an explosion of dust–gas mixtures. In order to prevent them from any consequences of potential explosions, active protection systems which use extinguishing powders, as the suppressing material, are more and more widely applied. It often happens that the industrial installations are additionally endangered by an action of mechanical vibrations. In the above-mentioned conditions, the extinguishing powder tends to aggregate, making the process of dispersing it in the protected areas more difficult. The results of research into optimization of the shape, number of igniters and miniaturization of the explosive charge mass are presented. In case of occurrence of the mechanical vibrations in the installations that cause aggregation of the suppressing powder, the best solution was modification of the perforated combustion chamber located inside the extinguisher. As a result of that, a certain amount of gases generated in the course of combustion of the main charge is directed over the membrane, where the gases crash a layer of aggregated powder. Thus, the process of pushing the powder out from a container towards the dispersing head improves considerably and consequently increases the efficiency of the explosion-suppressing process.score: 25collation: 664-67
Influence of lamination process on optical fiber sensors embedded in composite material
No full textabstractEN: In the paper we present the results of our research on optical fiber sensors embedded into composite material samples. We investigate the influence of the lamination process, axial orientation of an optical fiber sensor and coating of a fiber on stress monitoring of a composite material. In the paper we present two approaches to the case of composite condition monitoring, using a polarimetric fiber optic sensor as well as fiber Bragg gratings. We also present experimental evidence that interaction between a composite material and fiber optic sensors is very significant and depends on many factors such as fiber optic axial orientation and the coating layer surrounding an optical fiber.score: 25collation: 2275-228
A divide and conquer algorithm for constrained multibody system dynamics based on augmented Lagrangian method with projections-based error correction
No full textabstractEN: This paper presents a new parallel algorithm for dynamics simulation of general multibody systems. The developed formulations are iterative and possess divide and conquer structure. The constraints equations are imposed at the acceleration level. Augmented Lagrangian methods with mass-orthogonal projections are used to prevent from constraint violation errors. The proposed approaches treat tree topology mechanisms or multibody systems which contain kinematic closed loops in a uniform manner and can handle problems with rank deficient Jacobian matrices. Test case results indicate good accuracy performance dependent on the expense put in the iterative correction of constraint equations. Good numerical properties and robustness of the algorithms are observed when handling systems with single and coupled kinematic loops, redundant constraints, which may repeatedly enter singular configurations.score: 0collation: 871-88
Application of General Multibody Methods to Robotics
No full textabstractEN: In this chapter robotic applications of general multibody system (MBS) simulation methods, based on absolute coordinates formalism, are presented. Three typical problems, often encountered in robotics, are discussed: kinematic analysis with singular configuration detection, simulation of parallel robot dynamics investigated jointly with the robot control systems properties, and finally, simulation of a robot with flexibility effects taken into account. In case of singular configuration detection simplest types of singular configurations are analyzed – turning point and bifurcation point. The second case of MBS application is an example of parallel robot dynamic analysis when model based control is taken into account. The last part of the chapter is devoted to the analysis of complex, flexible power transmission mechanism carried out with general MBS formalism.score: 4collation: 131-15
Investigation of parameters of the multimode four-layer waveguide structures and their influence on the light propagation
No full textabstractEN: Investigation of parameters of the multimode four-layer waveguide structures and their influence on the light propagationscore: 7collation: 124-12