Kabatc J.,University of Technology and Life Sciences in Bydgoszcz
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2010
The new photoinitiating systems for free radical polymerization of multifunctional monomers composed of carbocyanine dye, 1,3,5-triazine derivative and heteroaromatic mercaptan were described. It was shown, that the polymerization abilities of such photoinitiatng systems are comparable with those observed for well-known cyanine borate two-component photoinitiating systems. The fluorescence quenching rate constants of tested sensitizer was about 2 x 1010 M-1s-1. Basing on the results of laser flash photolysis, the mechanism of the photochemical reactions occuring in the three-component photoinitiating system was proposed. © 2010 Wiley Periodicals, Inc.
Leppert T.,University of Technology and Life Sciences in Bydgoszcz
International Journal of Machine Tools and Manufacture | Year: 2011
At present coolants and lubricants are increasingly recognized as harmful factors for environment and machine operators' health. Industry and research institutions are looking for new means of reducing or eliminating the use of cutting fluids, both for economical and ecological reasons. This can be done if quality properties of machined surfaces and process parameters in dry and wet machining are comparable. This paper presents an investigation into the influence of cutting zone cooling and lubrication on surface roughness, waviness, profile bearing ratio and topography after turning C45 steel. Dry cutting and minimum quantity lubrication (MQL) results are compared with conventional emulsion cooling. Cutting forces and their components were put under examination as well. The experimental outcomes indicate that the cooling and lubrication conditions affect significantly the investigated process and surface properties. However, the impact of the cooling and lubricating technique depends to a large extent on the applied cutting parameters, namely the cutting speed and feed rate. Turning dry or with MQL with properly selected cutting parameters makes it possible to produce better surface topography characteristics than turning with conventional emulsion cooling. Apart from improving the surface properties the MQL mode of cooling and lubrication also provides environmental friendliness. © 2010 Elsevier Ltd. All rights reserved.
Osmialowski B.,University of Technology and Life Sciences in Bydgoszcz
Journal of Molecular Modeling | Year: 2012
Tautomerism in monomers/dimers and association of 2,5-dihydroxy-1,8- naphthyridine was studied at the DFT level recently recommended for studies of noncovalent interactions. Studied dimers are stabilized by double and triple hydrogen-bonding. In some associates the intermolecular proton transfer may take place. Transition state related to the double proton transfer reactions were calculated and discussed in terms of energetics, changes in atomic charges upon association, aromaticity (HOMA), properties of hydrogen bond critical point (QTAIM methodology) and geometry change during this reaction. It was found that double proton transfer is supported by third hydrogen bond or by weak secondary interaction. Some protons in transition states are shared between two basic atoms, while other are covalently bound only to one of them. The said process leads to replacement of secondary interactions of attractive character to repulsive and vice versa. Overall, results suggest that in subjected compound the triple hydrogen-bonded associate may be in equilibrium with double hydrogen-bonded dimer. © Springer-Verlag 2011.
Mikolajczyk T.,University of Technology and Life Sciences in Bydgoszcz
Applied Mechanics and Materials | Year: 2013
Paper presents the robot equipped with the tool to surface machining. To recognize the machining area USB camera mounted to robots wrist was used. Possibilities of using surface iew to self programming the surface finishing were shown. Special PC control system of industrial robot was used. © (2013) Trans Tech Publications, Switzerland.
Piatkowski T.,University of Technology and Life Sciences in Bydgoszcz
Mechanism and Machine Theory | Year: 2014
The paper presents a method of determination of parameters for LuGre and Dahl dynamic friction models. The method involves the use of numeric optimisation, in which the objective function is a minimisation of the sum of squares of relative errors between the actual and modelled friction hysteresis courses. It was specified that the limiting value of the cycle time of the signal, forcing the relative motion, above which the simulation of friction hysteresis in the presliding regime is not dependent on the velocity of displacement. The analyses of numerical results indicated that the parameters of dynamic models have limited the scope of application in relation to the normal forces exerted on the kinematic friction pairs, as opposed to the static friction models. © 2013 Elsevier Ltd.