The State Higher Vocational School in Walcz
Walcz, Poland
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Kowalski S.,The State Higher Vocational School in Walcz
Journal of the Balkan Tribological Association | Year: 2016

Investigation of fretting in the wheel sets of railway vehicles on the real object is technologically difficult. Large dimensions, weight and complicated design prevent the creation of an appropriate position. An additional problem is the removal of the connection. Traditional pressing-out of the wheel from axle would cause distortion the image of occurring wear. It was proposed here to apply a model for press-fit wheel-axle, which consists of a shaft and the sleeve, followed by wear testing carried out on the fatigue machine, thus allowing a bending of the rotation shaft corresponding to operating conditions of the wheel set when travelling in a straight line. This raises the question whether the results of research carried out on the model can be transferred to a real object. The answer to this question we get by using the theory of similarity, the mathematical tool of which is the dimensional analysis. The aim of the study was to propose such technological processes in the finish of the surface layer of the shaft, which will limit the development of fretting wear and will not affect significantly the total cost of production of wheel sets. Thus, for purposes of research were chosen the rolls with nitrogenised and surface-hardened layer and rolls with the roll-polished surface. The results of wear tests showed that all proposed technologies of finishing the top layer limit the development of fretting wear. An important issue is now the possibility to refer the results of model tests to the actual wheel set. Dimensional analysis carried out in this article confirms such a possibility.

Kaczorek E.,Poznan University of Technology | Salek K.,Poznan University of Technology | Guzik U.,University of Silesia | Dudzinska-Bajorek B.,The State Higher Vocational School in Walcz | Olszanowski A.,Poznan University of Technology
International Biodeterioration and Biodegradation | Year: 2013

A bacterial strain was isolated from soil that was contaminated with diesel oil and was used in our experiments. The strain was then phenotypically, biochemically and genetically tested and named as Achromobacter 4(2011). In order to examine the impact of long-term contact with diesel oil of bacterial cells, the strain was stored under different conditions - on standard nutrient agar plates and on agar plates with 50 μl diesel oil as a sole carbon and energy source. The results clearly indicated that longer contact with diesel oil led to changes in both the bacterial surface and biochemical properties, as well as the hexadecane monooxygenase activity. Moreover, the fatty acid profiles also changed, leading to an increased content of saturated fatty acids. In addition, the rates of biodegradation of diesel oil were higher even when supplemented with the surfactants - rhamnolipids and saponins. This work demonstrates that prolonged contact of microorganisms with diesel oil can lead to many changes, not only in biodegradation potential, but also in their surface and genetic properties. © 2012 Elsevier Ltd.

Kaczorek E.,Poznan University of Technology | Salek K.,Poznan University of Technology | Guzik U.,University of Silesia | Dudzinska-Bajorek B.,The State Higher Vocational School in Walcz
New Biotechnology | Year: 2013

Surface properties of newly isolated Stenotrophomonas maltophilia strain 6 were tested. The bacteria were stored in two different ways to determine the influence of hydrocarbons and surfactants on surface and enzymatic characteristics of the isolated strain. The influence of surface active agents, natural and synthetic, on membrane's lipid composition and cell surface hydrophobicity (CSH) was investigated. Our results indicate that long-term contact with diesel oil as a hydrophobic sole carbon source leads to the increased enzymatic activity of S. maltophilia strain 6 as well as to modification of fatty acids profiles and its facility to adhere to hydrophobic compounds. Among surfactants there were saponins and Triton X-100 which changed the composition of fatty acids the most, increasing the amount of branched acids. The comparison of fatty acid profiles with CSH of systems with diesel oil, rhamnolipids, saponins and Triton X-100 points out that the growing amount of hydroxy fatty acids corresponds to lower hydrophobicity. Moreover, CSH is a dynamic parameter which can change during cultivation of microorganisms. © 2012 Elsevier B.V.

Sapinski B.,AGH University of Science and Technology | Krupa S.,The State Higher Vocational School in Walcz
Smart Materials and Structures | Year: 2013

This paper summarizes a numerical analysis of the electromagnetic field, voltage and circuit properties and the cogging force in a vibration power generator comprising permanent magnets and a coil with a foil winding. The device converts the energy harvested from vibrations into electrical energy which is next used to vary the damping characteristics of a linear MR damper attached to the generator. The objective of the study is to propose a sufficiently efficient generator whose finally developed (target) version could be integrated with a small-scale MR damper to build a single device. Two design options for the device are numerically studied, the previously engineered generator 1 and the newly devised generator 2. Generator 1 incorporates two magnet systems having four magnets each and a single-section coil, while generator 2 comprises three magnet systems with four magnets each and a two-section coil. Calculations were performed to determine the electromagnetic field, voltage and current properties and the cogging force in the generators. The electromagnetic field parameters include the distribution of the magnetic field, the electrical potential field and the current density in the open turn and closed turn of the generators' coils. The voltage and current properties include electromotive force (emf) in the generators and the voltage, current, instantaneous power and energy of the magnetic field in the MR damper control coil which is represented by resistance parameter R and inductance parameter L. The cogging force expresses the magnetic interactions between the permanent magnet systems and ferromagnetic structural components of the generators. The occurrence of this force is very unfavourable and attempts should be made to reduce it through control of the parameters of the magnetic circuit components. On one hand, comparison of the numerical results for the electromagnetic field parameters and voltage and current properties revealed that for the predetermined RL parameters of the MR damper control coil, generator 2 seems to be more efficient than generator 1 and hence is more suitable for supplying the MR damper. On the other hand, comparison of the calculated cogging force levels revealed that its value tends to be lower in generator 1. It is reasonable to suppose that development of a final version of the generator with the defined structure and enhanced efficiency would have to involve some trade-off between the emf and the cogging force. © 2013 IOP Publishing Ltd.

Proniewicz E.,Jagiellonian University | Ozaki Y.,Kwansei Gakuin University | Kim Y.,Hankuk University of foreign Studies | Proniewicz L.M.,Jagiellonian University | And 2 more authors.
Journal of Raman Spectroscopy | Year: 2013

Kinetensin (KN) and its amino acids 1-8 fragment ([des-Leu9]KN), neuromedin N (NMN), and xenopsin (XP) and its two analogs (human XP-1/xenin-8 and XP-2) belong to the neurotensin family of peptides and are known to stimulate the growth of human tumors. In this work, we report surface-enhanced Raman scattering (SERS) studies of these peptides and discuss their structures, orientation, and mode of adsorption onto a colloidal assembly of apparently randomly adhering Ag spheres with diameters of approximately 20 - 25 nm. We show that small alternations in both the amino acid composition and tertiary structure, which induce striking biological in vitro, were responsible for the observed spectroscopic changes. Copyright © 2012 John Wiley & Sons, Ltd.

Podstawka-Proniewicz E.,Jagiellonian University | Kudelski A.,University of Warsaw | Kim Y.,Hankuk University of foreign Studies | Proniewicz L.M.,Jagiellonian University | Proniewicz L.M.,The State Higher Vocational School in Walcz
Journal of Physical Chemistry B | Year: 2011

The human, pig, and frog neurotensins and four single-site mutants of human neurotensin (NT), having the following modifications, [Gln4]NT, [Trp11]NT, [D-Trp11]NT, and [D-Tyr11]NT, were immobilized onto an electrochemically roughened silver electrode surface in an aqueous solution. The orientation of adsorbed molecules was determined from surfaceenhanced Raman scattering (SERS) measurements. A comparison was made between these structures to determine how the change upon the mutation of the neurotensin structure influences its adsorption properties. The SERS patterns were correlated with the contribution of the structural components of the aforementioned peptides to the ability to interact with the NTR1 G-protein receptor. Briefly, the SERS spectra revealed that the substitution of native amino acids in investigated peptides influenced slightly their adsorption state on an electrochemically roughened silver surface. Thus, human, pig, and frog neurotensins and [Gln4NT and [D-Tyr11]NT tended to adsorb to the surface via the tyrosine ring, the oxygen atom of the deprotonated phenol group of Tyr11 and thećH2 -unit(s), most probably of Tyr11, Arg9, and/or Leu13. The observed changes in the enhancement of the deprotonated Tyr residue SERS signals indicated a further parallel orientation of a phenol-O bond with regard to the silver surface normal for pig NT, [Gln4]NT, and [D-Tyr 11]NT, whereas the orientation was slightly tilted for human and frog NT. In the case of [Trp11]NT and [D-Trp11]NT, the formation of a peptide/Ag complex was confirmed by strong SERS bands involving the phenyl co-ring of Trp11/D-Trp11 and ćH 2- vibrations and the tilted and flat orientations of the two compounds with respect to the surface substrate. The spectral features were accompanied by a SERS signal caused by vibrations of the carboxyl group of C-terminal Leu13 and the guanidine group of Arg9. Reported changes in SERS spectra of L and D isomers were fully supported by generalized two-dimensional correlation analysis. Additionally, a combination of mutation-labeling and vibrational spectroscopy (Fourier-transform Raman and absorption infrared) was used to investigate the possible peptide conformations and environments of the tyrosine residues. © 2011 American Chemical Society.

Wojciechowska A.,Wroclaw University of Technology | Kochel A.,Wrocław University | Komorowska M.,The State Higher Vocational School in Walcz
Polyhedron | Year: 2011

The new five-coordination zinc(II) complex of formula [Zn(Im)(l-tyr) 2]2·5H2O consisting of l-tyrosine (l-tyr) and imidazole (Im) molecules as ligands was prepared as crystals and characterized by X-ray diffraction, IR-FIR vibrational and UV-Vis electronic spectroscopy. The [Zn(Im)(l-tyr)2]2·5H2O complex crystallizes in the orthorhombic crystal system and P2 1212 space group. The [ZnN2N′O 2] chromophore has distorted bipiramidal geometry with value of τ parameter 0.7. The sensitive intra and inter-molecular hydrogen bonds created the layers arrangement and the "pseudo-baskets" fashion. The intraligand charge transfer (ILCT) π-π* and π-π* transitions in the ligands molecule are corresponded to the intensity bands in the UV-Vis region. © 2011 Elsevier Ltd. All rights reserved.

Zborowski K.K.,Jagiellonian University | Sola M.,University of Girona | Poater J.,University of Girona | Proniewicz L.M.,Jagiellonian University | Proniewicz L.M.,The State Higher Vocational School in Walcz
Central European Journal of Chemistry | Year: 2013

Chelatoaromaticity (aromaticity of chelate complexes) has been recently recognized as an important property influencing the stability of chelate compounds. In this paper, aromaticity of various forms of 8-hydroxyquinoline (anion, neutral molecule, zwitterion and cation) as well as its chelate complexes with magnesium and aluminium ions are investigated. Aromatic properties of these compounds are analyzed using several aromaticity indices based on energetic, geometric, magnetic and electronic physical manifestations of this phenomenon. Results of performed calculations have shown different aromatic properties for the two rings (pyridine and benzene) occurring in the studied ligand. Aromaticity of these rings in metal complexes of 8-hydroxyquinoline is significantly higher than that in corresponding ligand anion. This means that during complexation the aromaticity of the ligand increases and the chelatoaromatic effect stabilizes the studied metal complexes. In contrast, metallocyclic rings of studied metal complexes have non-aromatic properties, and, consequently, the metallocyclic ring is not stabilized by chelatoaromaticity. We conclude that, in the complex, every 8-hydroxyquinoline unit and the metal ion are separated p-electronic systems. [Figure not available: see fulltext.] © 2013 Versita Warsaw and Springer-Verlag Wien.

Kramkowski K.,Medical University of Bialystok | Leszczynska A.,Medical University of Bialystok | Buczko W.,Medical University of Bialystok | Buczko W.,The State Higher Vocational School in Walcz
Pharmacological Reports | Year: 2015

Fibrinolysis is an action of converting plasminogen by its activators, like tissue- or urokinase-type plasminogen activators (t-PA, u-PA), to plasmin, which in turn cleaves fibrin, thereby causing clot dissolution and restoration of blood flow. Endothelial cells release t-PA, prostacyclin (PGI2) and nitric oxide (NO), the potent factors playing a crucial role in regulation of the fibrinolytic system. Since blood platelets can release not only prothrombotic, but also antifibrinolytic factors, like plasminogen activator inhibitor type-1 (PAI-1), they are involved in fibrynolysis regulation. Therefore agents enhancing fibrinolysis can be preferred pharmacologicals in many cardiovascular diseases. This review describes mechanisms by which major cardiovascular drugs (renin-angiotensin-aldosterone system inhibitors, statins, adrenergic receptors and calcium channel blockers, aspirin and 1-methylnicotinamide) influence fibrinolysis. The presented data indicate, that the influence of these drugs on endothelium-blood platelets interactions via NO/PGI2 pathway is fundamental for its antithrombotic and profibrinolytic action. We also described new approaches for intravital confocal real-time imaging as a tool useful to investigate mechanisms of thrombus formation and the effects of drugs affecting haemostasis and mechanisms of their action in the circulation. © 2015 Institute of Pharmacology, Polish Academy of Sciences.

Pralat K.,The State Higher Vocational School in Walcz
Experimental Techniques | Year: 2016

The results of experimental research determining the coefficient of thermal conductivity λ of selected species of wood have been presented in this article. During measurements, “hot wire” method was used, which belongs to one of the most interesting methods due to its simplicity, easiness of realization, and accuracy. Platinum Pt500 sensor was used during measurements, which along with the measuring system creates precise temperature measuring converter with voltage output. Temperature analogue converter was developed individually for the needs of this experiment, connected to the computer measuring system that consists of multifunctional output of 14-bit converter A/C type NI USB-6009 produced by National Instruments together with interactive software for registration and measurements of voltage signals. Measurements were registered using computer measuring system, with sampling time every 0.1 s. In this study,methods of interpretation measurement data are proposed. The biggest challenge in “hot wire” method is to find the time range (t1 –t2) to estimate the thermal conductivity of studied sample. For the needs of experiment, a computer program was written that enables fast calculation of values of thermal conductivity coefficients in different time intervals. Value of thermal conductivity for six species of wood was calculated. Calculated values were within the range 0.126–0.225 (W/(m K)) and were not different than literature values by 10 %. The lowest values were obtained for pine wood, the highest for hornbeam wood. General dependency of calculating the value λ of the wood on the basis of known value of density is proposed. © 2016, The Society for Experimental Mechanics, Inc.

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