Time filter

Source Type

Lema-Ruminska J.,University of Technology and Life Sciences in Bydgoszcz
Plant Cell, Tissue and Organ Culture | Year: 2011

Flow cytometry was used for analyzing DNA contents of nuclei isolated from in vitro grown somatic embryos, shoots and calli, as well as mammillae of in vivo grown shoots of cactus, Copiapoa tenuissima Ritt. formamonstruosa. Endoreduplication was detected in both in vitro grown somatic embryos, shoots and calli and in mammillae derived from in vivo grown shoots. However, the lowest ploidy levels ranged from 2C to 4C in somatic embryos, and reaching up to 32C for in vitro grown shoots and calli from mammillae. Whereas, ploidy levels of in vivo-derived mammillae ranged from 2C to 16C. The presence of 2,4-dichlorophenoxyacetic acid (2,4-D) in the culture medium had no influence on levels of ploidy of regenerated tissues. The mean genome size of cactus was calculated as 2C = 2. 87 ± 0. 05 picogram (pg). © 2011 Springer Science+Business Media B.V.

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.

Mikolajczyk T.,University of Technology and Life Sciences in Bydgoszcz
Applied Mechanics and Materials | Year: 2013

Paper shows system to surface shape and quality control in machining using industrial robot. To surface control videooptical methods were used. Surface shape was controlled using the special reverse engineering system. To surface roughness measure machined surface reflectivity method was used. Used own constructions non contact system was equipped with red laser light and USB camera. Wrist of robot was equipped with grinding tool. In paper shows some algorithms of presented processes. Shown too examples of experiments results in surface roughness measure in start end of grinding process. First trials of presented system shows possibility to build smart machining system for finishing of surface with unknown shape. © (2013) Trans Tech Publications, Switzerland.

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.

Mikolajczyk T.,University of Technology and Life Sciences in Bydgoszcz
Advanced Materials Research | Year: 2012

Paper describes the robots employment to surface manufacturing. In experiments were used IRb60 robot with modernized computer control system. Presented examples of robots using with stationary, rotational and inject tools. Stationary tools were used to cutting polystyrene foam and turning. Rotational, tool with its own drive, was used to milling and grinding mould surface. Inject tool was used to rapid prototyping using polyurethane foam. © (2012) Trans Tech Publications.

Kabatc J.,University of Technology and Life Sciences in Bydgoszcz | Jurek K.,University of Technology and Life Sciences in Bydgoszcz
Polymer | Year: 2012

N,N′-diethylthiacarbocyanine iodide (Cy) with two different compounds acting as co-initiators were used in the three-component photoinitiating systems for free radical polymerization of acrylate monomer. The steady state and time-resolved techniques were used to study the fluorescence quenching by co-initiators, as well as laser flash photolysis to investigate an electron transfer process, that occurs in these photoinitiating system (PIS). To investigate the key factors involved with visible-light activated radical polymerizations involving three-component photoinitiators, we used thermodynamic feasibility and kinetic considerations to study photopolymerizations initiated with thiacarbocyanine dye as a photosensitizer. The Rehm-Weller equation was used to verify the thermodynamic feasibility for electron transfer reaction. Experiments show, that the main interaction between the dye and both co-initiators occurs through its excited singlet state. It was concluded, that the key kinetic factors for efficient visible-light activated initiation process are summarized in two ways: (1) to retard back electron transfer and recombination reaction steps and (2) to use a secondary reaction step to consuming dye-based radical and regenerating the original photosensitizer. Basing on the study, it is known that, there are two possible mechanisms of generation of free radicals, which can start polymerization involving photoreducible series mechanism and parallel series mechanism (photoreducible-photooxidizable series mechanism). © 2012 Elsevier Inc. All rights reserved.

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.

Jackiewicz J.,University of Technology and Life Sciences in Bydgoszcz
Engineering Fracture Mechanics | Year: 2011

In the paper the modified Gurson model is developed for the simulation of damage growth and ductile fracture under low, medium and high stress triaxiality loadings. A new coalescence criterion is introduced based on a simple assumption that singular value of the effective stress triggers the coalescence of microvoids in materials. According to the introduced approach the void coalescence described by means of the modified Gurson model is not only determined by the so-called critical, constant void volume fraction but also by the stress triaxiality ratio. Computational simulations have been carried out for Al 2024-T351 aluminum specimens. In order to find some improvements of micromechanical damage models, two different approaches have been compared for modeling the shear driven microvoid coalescence under low stress triaxiality loadings. © 2010 Elsevier Ltd.

Kabatc J.,University of Technology and Life Sciences in Bydgoszcz
Polymer | Year: 2010

Three heteroaromatic thiols (2-mercaptobenzothiazole, 2-mercaptobenzoxazole and 2-mercaptobenzimidazole) were investigated in regard to their abilities as a co-initiator in free radical polymerization induced by cyanine dye/borate salt photoinitiating system. The kinetic results shown that the new three-component photoinitiating systems are more effective than two-component ones. The mechanism of photochemical and chemical processes occurring during the irradiation of the three-component initiators was proposed on the basis of the laser flash photolysis. The addition to the cyanine dye borate salt of a second co-initiator (thiol) results in the generation besides butyl radical the second free radical which can start the polymerization chain reaction. © 2010 Elsevier Ltd.

Loading University of Technology and Life Sciences in Bydgoszcz collaborators
Loading University of Technology and Life Sciences in Bydgoszcz collaborators