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Repozytorium publikacji
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Publikacje z roku 2013

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  • Efektywność sprężania krótkich wsporników słupa
    • Małgorzata Lachowicz
    2013

    Celem dysertacji było określenie efektywności zastosowania sprężania we wspornikach słupa przy dwuetapowej technologii procesu wykonawstwa. Wsporniki żelbetowe należą do elementów konstrukcji, które ulegają zarysowaniu we wczesnej fazie pracy. Pojawienie się rys budzi obawy, prowadzące do nie zawsze uzasadnionego zalecenia wzmocnienia. W tym przypadku często tylko sprężenie wsporników może być sposobem na ograniczenie procesu zarysowania w tym również ukośnego. W literaturze wciąż jednak znajduje się niewiele informacji dotyczących morfologii rys, mechanizmu niszczenia oraz nośności granicznej krótkich wsporników słupów sprężonych bez przyczepności (post tensioned). Dwuetapowe wykonywanie konstrukcji wsporczej, które może być zastosowane w procesie prefabrykacji lub modernizacji konstrukcji wsporczej jest do tej pory zagadnieniem nierozpoznanym. Dołączenie wspornika żelbetowego do istniejącego słupa, eliminuje możliwość tradycyjnego kotwienia zbrojenia głównego na końcu wspornika w postaci pętli, zalecanego zarówno przez normę polską [52] jak i europejską [54]. Przeprowadzone badania eksperymentalne pozwoliły na rozpoznanie przydatności sprężania w technologii dwuetapowej, przy wykonywaniu zamocowania wsporników do istniejących słupów. Zarówno wsporniki, jak też przylegające do nich obszary słupów, w których są zamocowane zaliczamy do tzw. obszarów typu D, dla których nie obowiązuje zasada płaskich przekrojów przyjęta przez Bernoulliego dla belek zginanych. Dodatkowym aspektem, który należy uwzględnić podczas analizy teoretycznej jest działanie siły sprężającej istotnie wpływającej na nośność oraz morfologię zarysowania wsporników. Celem części teoretycznej było wyznaczenie obciążenia powodującego pojawienie się pierwszych rys: w narożu rozciąganym i przede wszystkim rysy ukośnej w środkowym obszarze wspornika, która często sygnalizuje nadmierne jego wytężenie. Wykorzystując model kratownicowy określono nośność takich wsporników. Ponadto siłę niszczącą wyznaczono bazując na hipotezie ścinania–tarcia i jej modyfikacjach uwzględniających działanie siły sprężającej. Na tej podstawie sformułowano tezę pracy, która brzmi następująco: sprężanie ogranicza zarysowanie wspornika, zwiększa jego nośność a jego prefabrykacja rozszerza możliwość rewitalizacji. Stosowanie zbrojenia sprężającego może być skuteczną alternatywą dla tradycyjnego zbrojenia wiotkiego w tego typu rozwiązaniu konstrukcyjnym.

  • Effect of Bi2O3 Excess on Morphology and Structure of BiNbO4 Ceramics
    • Dionizy Czekaj
    • Agata Lisińska-Czekaj
    • Katarzyna Osińska
    • Krzysztof Biernacki
    2013 Pełny tekst ARCHIVES OF METALLURGY AND MATERIALS

    Goal of the present research was to fabricate BiNbO4 ceramics from the mixture of powders by the solid state reaction route and pressureless sintering at various temperatures (TS =8700C and TS =9100C) and study microstructure, phase composition and crystalline structure of BiNbO4 ceramics. Four batches were fabricated and examined, namely the one fabricated from the stoichiometric mixture of reagent – grade oxide powders, viz. Bi2O3 and Nb2O5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2O3. It was found that apart from the main orthorhombic -BiNbO4 phase additional phases, namely tetragonal Bi5Nb3O15, and cubic Bi3NbO7 are possible to form from the mixture of bismuth oxide and niobium oxide. It was found that -BiNbO4 ceramics exhibited the orthorhombic symmetry identified as Pnna (52). However, small differences in elementary cell parameters were found for the samples sintered from stoichiometric and non-stoichiometric mixture of initial powders.

  • Effect of Coating Material Properties on Tilting-pad Thrust Bearing Performance
    • Michał Wodtke
    • Michał Wasilczuk
    2013

    Polymer lined tilting-pad bearings demonstrate many advantages over traditional bearing systems. Bearings with a polymer layer in comparison with a babbitted layer show, for example: lower value of friction coefficient (important during start/stops), higher fatigue strength of the coating, better distribution of the load on individual pads due to lower elasticity of the polymers, wider range of operational temperatures or the ability to carry higher specific loads. Polymer lined bearings are, of course, not free from some disadvantages, as for example some problems with reliable temperature monitoring of the bearing surface due to low thermal conductance of the polymer or necessity of a special additional intermediate layer to fix the polymer to a steel pad body. PTFE and PEEK based composites are most often used in bearing engineering practise. Both materials have a low value of thermal conductance, but differ from the each other in mechanical properties. Stiffness (Young modulus) of the PEEK is about an order of magnitude higher than that of PTFE. The influence of the polymer lining mechanical properties on the bearing performance has not been systematically studied for thrust bearing so far. In this paper, the effect of mechanical properties of the coating material on a tilting-pad thrust bearing performance was investigated. Three coating material properties were considered: Babbitt, PEEK and PTFE. Analysis was carried out with the use of an experimentally verified TEHD model of the bearing pad, which utilized FEM and CFD in one task. The results of calculations (temperature, pressure and oil film thickness profiles) were compared. The results show significant differences in bearing performance depending on coating properties. In general, this analysis allowed the authors to show and assess the changes in flow phenomena caused by changes in coating material properties.

  • Effect of Cr and Mn doping on ferroelectric and dielectric properties of Li1.72Na0.28Ge4O9 single crystals
    • A. Jasik
    • S.m. Kaczmarek
    • K. Matyjasek
    • Ryszard Jan Barczyński
    2013 PHASE TRANSITIONS

    Li1.72Na0.28Ge4O9 single crystals pure and slightly doped with chromium and manganese, obtained by Czochralski growth, were investigated for their ferroelectric and dielectric properties. The change in stoichometry of Li2− x Na x Ge4O9 (x = 0.28) crystals doped with Cr and Mn (0.1 mol.%) had an influence on the value of ferroelectric-to-paraelectric phase transition temperature, T c. The applied doping affects the T c value by no more than 10 K. Moreover, we observed strong anisotropy of physical properties of lithium tetragermanate crystals. It has been found that Li1.72Na0.28Ge4O9 crystal doped with transition metal ions reveals ferroelectric activity in the b-crystallographic direction, (010 in Pca21 space group), below T c = 260 K. This activity, measured by the value of electrical permittivity, is much less for doped crystals than pure ones. Dielectric permittivity ε′, conductivity and loss tangent of the crystals, all as the function of temperature in the range of 113–433 K, at frequency between 1 Hz to 1 MHz were measured. The values of conductivity activation energies, E a, were estimated. Hysteresis loops as well as coercive field and spontaneous polarization were measured and calculated. Switching current transients were analyzed.

  • Effect of electrode resistance on admittance spectra of planar organic device carrying SCLC and on charge carrier mobility extracted from susceptance
    • Grażyna Jarosz
    • Ryszard Signerski
    2013 SYNTHETIC METALS

    The work presents small signal admittance spectra of a sandwich system with thin organic layer carrying a space charge limited current. The effect of series resistance of electrodes on the spectra is discussed. Spectra of small signal capacitance are added to get more detailed insight. The analysis performed shows that the series resistance can affect both parts of small signal response within a whole range of frequency. Moreover, it can also affect the value of charge carrier mobility extracted from -delta(B) function.

  • Effect of glycolysate obtained from polyurethane wastes on mechanical properties of rubber materials
    • Janusz Datta
    • Małgorzata Szarało
    • Ewa Głowińska
    • Marcin Włoch
    2013

    The paper presents the possibility of utilization of wastes from polyurethane foams. In this work the results of mechanical investigations of materials obtained from natural rubber mixtures with a mixture of glycolysate and biodiesel glycerine as a plasticizer are described. The measurements of mechanical properties showed rather good tensile strength, elongation at break and modules of extensions M100%, M200%, M300% of obtained materials. Glycolysates obtained from polyurethane wastes can be an alternative to the substances obtained from petroleum which are currently the most commonly used plasticizers.

  • Effect of initial imperfection on buckling of thin-walled I columns
    • Czesław Szymczak
    • Marcin Kujawa
    2013

    Effects of initial geometrical imperfections on critical buckling loads of thin-walled I columns are investigated. Torsional and flexural buckling are taken into account. The column behaviour is described in accord to the theory of thin-walled beams with nondeformable cross-section. Some numerical examples and conclusions related to effects of imperfections on properties of the critical loads are presented.

  • Effect of modified soybeen oil amount on rheological characteriza-tion of polyurethane pre-polymers
    • Ewa Głowińska
    • Janusz Datta
    2013

    Polyurethanes (Pu’s) are the polymeric materials which have got urethane groups in the structure. The properties of Pu’s depend both on the method of preparation and monomers used. Polyurethanes are produced by two methods known as one step or two step method called as “pre-polymers method”, especially for the case of segmented polyurethanes (SPU’s). These materials are thermoplastic block copolymers of the (AB)n type consisting of alternating sections of hard segments, composed of a diisocyanate and a low molecular weight diol chain extender, and soft segments, generally composed of various types of polyols, also called macrodiols. In the two steps method for SPU synthesis, a pre-polymer is first obtained and then chain extended is added to the reaction system.Using novel components in polyurethane synthesis leads to change the rheological properties of pre-polymers what effect on characteristic of polyurethane systems during their production and the change in gel point of polyurethane materials. The aim of this work was determined the rheological properties of pre-polymers ob-tained using bio-based polyols. Influence on temperature measurements on this characteristic was also investigated.

  • Effect of slightly crosslinked butyl rubber and compatibilizer additives on properties of recycled polyethylene-ground tire rubber blends
    • Krzysztof Formela
    • Józef Haponiuk
    • Przemysław Stankiewicz
    • Jacek Ryl
    • Katarzyna Końska
    2013 Przemysł Chemiczny

    Slightly crosslinked butyl rubber, (PhMe2CO)(2) and maleic anhydride were added as compatibilizer to the recycled polyethylene-ground tire rubber blends. Recycled postprodn. and postconsumer (shredded bottle caps) polyethylene wastes were used. The thermoplastic compns. were studied for statistic and dynamic mech. properties and morphol. The addn. of butyl rubber resulted in a decrease of the tensile strength and hardness of the blends and an increase in compatibility of the blend components. Use of (PhMe2CO)(2) and maleic anhydride resulted in an improvement of mech. strength of the blends.

  • Effect of the absence of clear contractual conditions for the pur-chase of combined heat and power systems through public tenders
    • Zbigniew Kneba
    • Maciej Ziółkowski
    2013 Pełny tekst Combustion Engines

    W artykule przedstawiono dyskusję konsekwencji stosowania różnych podejść do obliczeń kontraktowych parametrów technicznych zespołów kogeneracyjnych. Obliczenia te wykonywane są na potrzeby oferty przygotowywanej w związku z ogłoszeniem przetargu publicznego na zakup siłowni kogeneracyjnej. Brak precyzyjnych zasad określających warunk, i jakie należy przyjąć do wyznaczania parametrów kontraktowych zespołów kogeneracyjnych umożliwia dowolne kreowanie warunków obliczeniowych i tolerancji. Sytuacja ta powoduje, że poprawne porównanie ofert przedstawionych przez różnych producentów często jest niemożliwe. Z drugiej strony częsty brak szczegółowej kontroli przyjętych warunków kontraktowych, a czasami niska świadomość techniczna po stronie zamawiających i brak specjalistycznego nadzoru powoduje dokonywanie nieracjonalnych wyborów. W artykule przedstawiono przykłady swobodnego podejścia do wyznaczania parametrów technicznych zespołów kogeneacyjnych. Zaproponowano również rozwiązania mające na celu ujednolicenie warunków kontraktowych, które powinny być narzucane podczas organizowania przetargów publicznych na zakup siłowni kogeneracyjnych.

  • Effect of underwater local cavity welding method conditions on diffusible hydrogen content in deposited metal
    • Dariusz Fydrych
    • Grzegorz Rogalski
    2013 Welding International

    One of the methods with great potential for applications in underwater repairs is local cavity welding. In local cavity method, cooling conditions and diffusible hydrogen amount in weld metal are nearly the same as those existed during welding in the air. This paper presents the results of literature survey and preliminary tests of the effect of local cavity welding conditions on diffusible hydrogen amount in a deposited metal. A Plackett–Burman design was applied to screen seven parameters: thickness of elastic cover, stick-out of electrode wire, welding current, voltage, travel speed of welding, salinity of water, and flow rate of shielding gas.

  • Effect of waviness and roughness components on transverse profiles of turned surfaces
    • Adam Boryczko
    2013 MEASUREMENT

    This paper presents the authors method of simultaneous analysis of roughness and waviness irregularity components, with the aim of better defining the key qualities and characteristics.Periodical surface machining traces may be analyzed spectrally, with the irregularity's peaks and troughs being used to define the wave's amplitude.In this work the standard composition for filtering waviness and roughness components of a surface is utilised.The method of digitally measuring the irregularity frequency ranges for the purposes of their spectral analysis is first presented. These results are then used to match the frequency ranges with the main irregularity components.A cumulative amplitude spectrum comprising both irregularity components is proposed to establish the relative contributions of the two components in the frequency spectrum. Comparative assessment of the error contributions from the form, waviness and surface roughness components gives a more complete image of the analysed surface topography. This also enables simultaneous evaluation of these components in different frequency spectra of the surface's geometrical structure.

  • EFFECTS OF DOPING ON STRUCTURE AND PHASE TRANSITION OF HIGH TEMPERATURE PROTON CONDUCTOR LaNb1-xMxO4-σ (M=As, Sb, V, Ta AND X=0,05 TO 0,3)
    • Sebastian Lech Wachowski
    • Aleksandra Dorota Mielewczyk-Gryń
    • Maria Gazda
    2013 Biuletyn Polskiego Stowarzyszenia Wodoru i Ogniw Paliwowych

    In this work synthesis of lanthanum orthoniobate has been done. Doping by arsenic, antimony, vanadium or tantalum in 5% to 30% have been introduced. The relationship between doping type and percentage and structural properties of the material have been investigated.

  • Effects of Salvia officinalis and Thymus vulgaris on oxidant-induced DNA damage and antioxidant status in HepG2 cells
    • Katarína Kozicsa
    • Veronika Klusová
    • Annamaria Srancikowa
    • Pavol Mučaji
    • D Slamenova
    • Ľubica Hunáková
    • Barbara Kusznierewicz
    • Eva Horváthová
    2013 Pełny tekst FOOD CHEMISTRY

    Salvia officinalis (SO) and Thymus vulgaris (TV) are medicinal plants well known for their curative powers. However, the molecular mechanisms responsible for these abilities of sage and thyme have not been fully understood yet. In this study we investigated the composition and the quantitative estimation of plant extracts, the protective effects of plant extracts against hydrogen peroxide- and 2,3-dimethoxy-1,4 naphthoquinone-induced DNA damage, and levels of enzymatic and non-enzymatic antioxidants (superoxide dismutase, glutathione peroxidase, glutathione) in human HepG2 cells. To measure antioxidative activity of plant extracts we used three assays: 1,1 diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,20-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The results showed that the oxidant-induced DNA lesions were significantly reduced in cells pre-treated with the plant extracts studied. The observed DNA-protective activity could be explained by both elevation of GPx activity in cells pre-treated with SO and TV and antioxidant activity of SO and TV.

  • Effects of social media communication on brand equity and brand purchase intention
    • Bruno Schivinski
    2013

    The author studied the effect of two different social media communication on brand equity and brand purchase intention. A total of 504 data sets were generated through a standardized online-survey and analysed with structural equation modeling. The results of the empirical study showed that both firm-created and user-generated social media communication influenced brand equity, consequently impacting brand purchase intention. This study also investigated the direct and indirect effects of social media communication on brand purchase intention. The results show that there is a partial mediation across firm-created social media communication and purchase intention; and a full mediation across user-generated social media communication and purchase intention. This study also offers insights for brand and marketing managers.

  • Effects of the polyhistidine tag on kinetics and other properties of trehalose synthase from Deionococcus geothermalis
    • Anna Panek
    • Olga Pietrow-Tobiszewska
    • Paweł Filipkowski
    • Józef Synowiecki
    2013 Pełny tekst Acta Biochimica Polonica

    Two recombinant trehalose synthases from Deinococcus geothermalis (DSMZ 11300) were compared. A significant influence of the artificial polyhistidine tag was observed in protein constitution. The recombinant trehalose synthase from D. geothermalis with His6 -tag has a higher K m value of 254 mM, in comparison with the wild-type trehalose synthase (K m 170 mM), and displayed a lower activity of maltose conversion when compared to the wild type. Moreover, differences in properties like temperature, pH, thermal- and pH-stability were observed. Presence of the histidine tag caused a decrease of thermal resistance in case of trehalose synthase with His6 -tag. These data confirmed a suggestion that the introduction of the histidine domain produces in some seldom cases undesirable changes in the protein.

  • Effects of the preheating laser treatment on microstructure and corrosion resistance of Ti6Al4V bioalloy
    • Magdalena Jażdżewska
    • Andrzej Zieliński
    • Igor Skalski
    • Beata Majkowska-Marzec
    2013 Pełny tekst Engineering of Biomaterials / Inżynieria Biomateriałów

    The laser remelting of the Ti6Al4V alloy was made on specimens pre-heated at elevated temperatures. The laser treatment effected in change of microstructures of surface layers and an appearance of blisters and numerous cracks. The corrosion tests demonstrated the decrease in corrosion resistance for each preheating temperature. The observed effects were attributed to negative influence of excessive compressive stresses with no substantial relation of cracking phenomenon on pre-heating and its temperature.

  • Effects of V2O5 Additive on Structure and Dielectric Properties of BiNbO4 Ceramics
    • Agata Lisińska-Czekaj
    • Dionizy Czekaj
    • Katarzyna Osińska
    • Małgorzata Adamczyk
    2013 Pełny tekst ARCHIVES OF METALLURGY AND MATERIALS

    Goal of the present research was to investigate the influence of V2O5 additive on the structure and dielectric properties of BiNbO4 ceramics. To fabricate BiNbO4 ceramics with V2O5 added the solid state reaction route and pressureless sintering was utilized. Thus obtained ceramics was characterized in terms of its microstructure (SEM), chemical composition (EDS), phase composition and crystalline structure (X-ray phase and structural analysis, respectively). Also dielectric properties in both temperature and frequency domains were investigated. The impedance spectroscopy was utilized for dielectric characterization and the measurements of complex impedance were performed within the frequency range =10Hz–1MHz and temperature range T =RT-550C. It was found that V2O5 additive changed slightly lattice parameters of BiNbO4 ceramics, decreased porosity of samples and revealled relaxation phenomena within the frequency ranges =102–103 Hz and =105–106 Hz at temperature T>285C.

  • Efficiency of linear and non-linear classifiers for gas identification from electrocatalytic gas sensor
    • Paweł Kalinowski
    • Łukasz Woźniak
    • Anna Strzelczyk
    • Piotr Jasiński
    • Grzegorz Jasiński
    2013 Pełny tekst Metrology and Measurement Systems

    Electrocatalytic gas sensors belong to the family of electrochemical solid state sensors. Their responses are acquired in the form of I-V plots as a result of application of cyclic voltammetry technique. In order to obtain information about the type of measured gas the multivariate data analysis and pattern classification techniques can be employed. However, there is a lack of information in literature about application of such techniques in case of standalone chemical sensors which are able to recognize more than one volatile compound. In this article we present the results of application of these techniques to the determination from a single electrocatalytic gas sensor of single concentrations of nitrogen dioxide, ammonia, sulfur dioxide and hydrogen sulfide. Two types of classifiers were evaluated, i.e. linear Partial Least Squares Discriminant Analysis (PLS-DA) and nonlinear Support Vector Machine (SVM). The efficiency of using PLS-DA and SVM methods are shown on both the raw voltammetric sensor responses and pre-processed responses using normalization and auto-scaling.

  • Efficiency of Wastewater Treatment in Single-Family Constructed Wetlands in Kaszuby Lake District
    • Hanna Obarska-Pempkowiak
    • Magdalena Gajewska
    • Ewa Wojciechowska
    2013 Pełny tekst Rocznik Ochrona Środowiska

    In the paper results of investigation upon three different configurations of single family treatment wetlands were presented. It was indicated that the application of treatment wetlands for single family effluent is a effective and sustainable solution for wastewater treatment in the rural areas. In spite of the receiving higher concentration of pollutants in comparison to the TWs operated in Europe and USA analysed TWs ensure very effective removal of organic matter: BOD5 up to 92.0% and biogenic compounds: TN up to 77.0% and TP up to 66.0%. The configuration consisting of two vertical subsurface flow beds working in series ensured the highest efficiency removal and the lowest pollutants concentration in the final effluent.