2014 - Publications Repository - Gdańsk University of Technology

Show publications from the year

Publications from the year 2014

Show all

Influence of electric, magnetic and electromagnetic fields on the circadian system – current stage of knowledge
- Bogdan Lewczuk
- Grzegorz Redlarski
- Arkadiusz Żak
- Natalia Ziółkowska
- Barbara Przybylska-Goronowicz
- Marek Krawczuk
2014 Full text JOURNAL OF BIOMEDICINE AND BIOTECHNOLOGY
One of the side effects of each electrical device work is the electromagnetic field generated near its workplace. All organisms, including humans, are exposed daily to the influence of different types of this field, characterized by various physical parameters. Therefore, it is important to accurately determine the effects of an electromagnetic field on the physiological and pathological processes occurring in cells, tissues and organs. Numerous epidemiological and experimental data suggest that the extremely low frequency magnetic field generated by electrical transmission lines and electrically-powered devices as well as the high frequencies electromagnetic radiation emitted by electronic devices have a potentially negative impact on the circadian system. On the other hand, several studies have found no influence of these fields on chronobiological parameters. According to the current state of knowledge, some previously proposed hypotheses, including one concerning the key role of melatonin secretion disruption in pathogenesis of electromagnetic-field induced diseases, need to be revised. This article reviews the data on the effect of electric, magnetic and electromagnetic fields on melatonin and cortisol rhythms - two major markers of the circadian system as well as on sleep. It also provides the basic information about the nature, classification, parameters and sources of these fields.
Influence of electrode geometric arrangement on the operation of narrow circular electrostatic precipitator
- Anna Niewulis
- J. Podliński
- Artur Berendt
- Jerzy Mizeraczyk
2014 International Journal of Plasma Environmental Science & Technology
In this work the influence of electrode geometric arrangement on the operation of a circular electrostatic precipitator (ESP) was investigated using Particle Image Velocimetry (PIV) method. The ESP was a glass circular cylinder (29 mm in diameter, 300 mm long) equipped with a wire discharge electrode and circular-cylinder collecting electrode. The stainless-steel discharge wire electrode (0.23 mm in diameter, 100 mm long) was mounted either in the centre (concentric case) or off centre of the cylinder (eccentric case), parallel to the cylinder axis. The circular-cylinder electrode was grounded. Positive voltage up to 10 kV was supplied to the wire-electrode through a 10 MΩ resistor. Air flow seeded with a cigarette smoke was blown axially along the ESP duct with an average velocity of 0.9 m/s. Also the case without forced axial flow was studied. The results showed that the eccentricity of the wire electrode with regard to the ESP axis is an important parameter influencing the operation of the circular ESP. Regardless of the discharge current intensity, a small shift of the wire electrode from the ESP axis (the eccentricity smaller than 8%) did not change the discharge current intensity at constant operating voltage. However, when the eccentricity of the wire electrode exceeded 8%, the discharge current intensity increased with increasing shift of the wire electrode from the ESP axis at constant operating voltage.
Influence of geometrical imperfections on stresses in cylindrical shells
- Dariusz Kowalski
2014
Results of the numerical analysis of the shells of storage tanks of 50 000 m3 capacity with geometrical imperfections are presented in the paper. Results were verified by tensometric tests performed on the real tank. It was recognized that real geometrical imperfections cause increase of stresses in the tank construction by 30%.
Influence of heterogeneous air entry pressure on large scale unsaturated flow in porous media
- Adam Szymkiewicz
- Insa Neuweiler
- Rainer Helmig
2014 Full text Acta Geophysica
The paper presents numerical simulations of water infiltration in unsaturated porous media containing coarse-textured inclusions embed- ded in fine-textured background material. The calculations are performed using the two-phase model for water and air flow and a simplified model known as the Richards equation. It is shown that the Richards equation cannot correctly describe flow in the presence of heterogeneities. How- ever, its performance can be improved by introducing appropriately de- fined effective capillary and permeability functions, representing large- scale behaviour of the heterogeneous medium.
Influence of low-temperature physical hardening on stiffness and tensile strength of asphalt concrete and stone mastic asphalt
- Józef Judycki
2014 CONSTRUCTION AND BUILDING MATERIALS
This paper presents laboratory testing of stiffness modulus and indirect tensile strength of three asphalt concrete (AC) and three stone mastic asphalt (SMA) mixes after isothermal storage at temperature of -20oC, at different time intervals up to 16 days. The tests under repeated dynamic loading showed physical hardening of all tested mixes which was manifested by an evident increase of their stiffness moduli after isothermal storage. Contrary to expectations, the tests on all mixes did not show any evident changes of the indirect tensile strengths which after isothermal storage remained almost constant, within normal scatter range. The differences in the physical hardening of asphalt concrete AC and stone mastic asphalt SMA were found. At the beginning of isothermal storage at -20oC the physical hardening was slower for the SMA. After 5–16 days of storage the SMA showed greater physical hardening than the asphalt concrete AC. Two measures which allowed the quantification of intensity of the physical hardening were introduced.
Influence of metallic porous microlayer on pressure drop and heat transfer of stainless steel plate heat exchanger
- Jan Wajs
- Dariusz Mikielewicz
2014
The experimental analysis of passive heat transfer intensification in the case of plate heat exchanger has been carried out. On the heat transfer surface of heat exchanger the metallic porous layer was created. The experiment was accomplished in two stages. In the first stage the commercial stainless steel gasketed plate heat exchanger was investigated, while in the second one – the identical heat exchanger but with the modified heat transfer surface. The direct comparison of thermal and flow characteristics between both devices was possible due to the assurance of equivalent conditions during the experiment. Equivalent conditions mean the same volumetric flow rates and the same media temperatures at the inlet of heat exchangers in the corresponding measurement series. Experimental data were collected for the single-phase convective heat transfer in the water-ethanol configuration. The heat transfer coefficients were determined using the Wilson method.
Influence of meteorogical conditions om PM10 concentration in Gdańsk
- Michalina Bielawska
- Waldemar Wardencki
2014 International Proceedings of Chemical Biological and Environmental Engineering
The paper presents the investigation of influence of meteorological conditions on the concentration of PM!) in Gdańsk in 2011 year. on the examples of episodes og high concentrations in this year. The results have shown the most crucial factors for high episodes of PM10: anticyclone atmospheric circulation, stable atmosphere conditions, low wind velocity and the occurence of inversion layer.
Influence of nodes with positive eccentricity on load-carrying capasity of truss' top chords in trusses made of welded cold-formed members.
- Małgorzata Gordziej-Zagórowska
- Elżbieta Urbańska-Galewska
2014
In order to establish the influence of eccentric crossing of truss members on the load-carrying capacity of the folded chord of a hat-section truss, a research model was created and preliminary numerical analysis of the truss was performed with the use of Marc Mentat programme. Distorial instability of crossheads caused by deviation of loose (unmounted) channel section web’s bends was observed. Due to the slenderness of the section’s walls (class 1), further numerical analysis will be required. Non-linear material analysis with the use of an elastic and plastic model with additional support, as well as buckling analysis for specific imperfection values are to be performed.
Influence of Phase Composition on Dielectric Properties of Bismuth-Based Ceramics with Scheelite-Type Structure
- Dionizy Czekaj
- Agata Lisińska-Czekaj
2014 Key Engineering Materials
Goal of the present research was to study dielectric properties of BiNbO4 ceramics fabricated by solid state reaction route followed with pressureless sintering. The samples were fabricated from the mixture of oxides, viz. Nb2O5 and Bi2O3. Apart from stoichiometric amount an excess of 3%, 5% and 10% by mole of Bi2O3 was used. It was found that an excess amount of Bi2O3 oxide caused formation of Bi5Nb3O15 minor phase in amount of 9wt%, 18wt% and 25wt%, respectively. The dielectric properties were studied by impedance spectroscopy within the frequency range ν=20Hz1MHz and temperature range T=RT550°C. It was found that the presence of the minor phase in amount of 18wt% caused a decrease in dielectric losses of the material under studies.
Influence of pitting corrosion on fatigue and corrosion fatigue of ship structures. Part I: pitting corrosion of ship structures.
- Marek Jakubowski
2014 Full text Polish Maritime Research
The paper is a literature survey focused on pitting corrosion and its influence on fatigue of ship and offshore steels. Mechanisms of short- and long-term pitting corrosion in marine environment have been described including pit nucleation and growth phases. Some models of pit growth versus time of exposure have been presented. Some factors which influence the pit growth have been discussed briefly.
Influence of plastic deformation on stray magnetic field distribution of soft magnetic steel sample
- Zbigniew Usarek
- Bolesław Augustyniak
- Marek Augustyniak
- Marek Chmielewski
2014 IEEE TRANSACTIONS ON MAGNETICS
The effect of various combinations of conditions, i.e., presence of the Earth’s magnetic field during and after deformation on the distribution of stray magnetic field of S355 steel sample, which is locally deformed, was investigated. Some of the stages of the experiment were carried out in zero magnetic field. Compensation of the Earth’s magnetic field was obtained by the application of a pair of Helmholtz coils. These coils are able to produce homogeneous field compensating Earth’s magnetic field over the full length of the sample. Stray magnetic field measurements were carried out along the longest dimension of the sample using the probe consisting of mutually perpendicular sensors allowing the simultaneous measurement of two magnetic field components, i.e., tangential and normal to a surface of the sample. Research has shown that there is a correlation between the level of plastic deformation of the investigated sample and the distribution of stray magnetic field. It was found that the nature of stray magnetic field of the sample depends on presence of external magnetic field during unloading. An attempt was also made, with the finite-element analysis, to verify experimentally obtained stray magnetic field distribution of undeformed sample.
Influence of pyrolysis atmosphere on the lithium storage properties of carbon-rich polymer derived SiOC ceramic anodes
- V.s. Pradeep
- Magdalena Graczyk-Zajac
- Monika Wilamowska-Zawłocka
- Ralf Riedel
- G.d. Soraru
2014 SOLID STATE IONICS
Polymer derived carbon-rich SiOC ceramics are prepared from polysiloxane precursors through a pyrolysis process at 1000 °C using pure argon and argon/hydrogen mixture as pyrolysis atmosphere. The precursor is synthesized from a linear (Si–H)-containing polysiloxane cross-linked with divinylbenzene using hydrosilylation reaction in the presence of a platinum catalyst. Pyrolysis in Ar/H2 mixtures, compared to the treatment under pure Ar, results into a decrease of the concentration of C dangling bonds as revealed by electron spin resonance (ESR) measurements. The amount of free carbon phase is 10 wt.% lower in the sample pyrolysed in a Ar/H2 mixture, while the ratio of hydrogen to free carbon remains constant for both, in Ar and in Ar/H2 pyrolysed samples. The sample prepared under Ar/H2 mixture shows an excellent cycling stability with an increase in the specific capacity of about 150 mAhg− 1 compared to its analogues pyrolysed in pure argon atmosphere
Influence of selected submicron inorganic particles on mechanical and thermo-mechanical properties of unsaturated polyester/glass composites
- Janusz Datta
- Marcin Włoch
2014 JOURNAL OF REINFORCED PLASTICS AND COMPOSITES
In this paper, the influence of different submicron-scaled particles (zinc oxide, titanium dioxide, or silica) on mechanical and thermo-mechanical properties of unsaturated polyester matrix composites reinforced with glass fabric was investigated. Surface morphology of obtained composites was also examined. At first inorganic particles were mechanically dispersed into unsaturated polyester resin system as per the calculated weight ratio (2 or 4 wt% of polymer matrix). For prepared liquid dispersions viscosity was measured. Composites were produced by using hand lay-up method and contained 39–41 wt% of glass fibers. The flexural and dynamic mechanical analyses were carried out for each group of fabricated polyester/glass composites. All results were compared with the control samples (without submicron particles). It was found that addition of 2 wt% ZnO or TiO2 to unsaturated polyester resin enhanced the flexural strength and flexural modulus of composites. Dynamic mechanical analysis showed the increase of storage and loss modulus. Similar effect of submicron-scaled inorganic particles on Tg value of composites was observed. The scanning electron microscopic analysis of prepared composites showed good dispersion of submicron particles in polymer matrix and generally absence of voids was also observed.
Influence of stirrups in a concrete shell on strengthening reinforced concrete column
- Marek Kin
2014
Twelve concrete columns, with a 150x150mm square section and three columns with a circular section (d=200mm), are tested to investigate the effect of strengthening by RC jacket. Based on a confined concrete model for axial static loading, an analytical methods, reported in the literature are proposed to predict the behavior of columns with RC jacket. The results support the conception that the effect of strengthening depends strongly on technology and many factors connected with three-dimensional state of stress. In many cases design procedures have not yet been able to provide an adequate solution.
Influence of the internal electrolyte composition on amperometric sulphur dioxide sensor properties
- Anna Strzelczyk
- Grzegorz Jasiński
- Bogdan Chachulski
2014 Elektronika : konstrukcje, technologie, zastosowania
In this work investigation of an amperometric sulphur dioxide sensor with a liquid electrolyte, a mercury sulphate reference electrode and solid polymer electrolyte (Nafion) covered with gold as a working electrode properties is presented. The main goal of this research is to determine the influence of internal electrolyte composition on the sensor properties. Sensor filled with 1M and 5M sulphuric acid has been studied.
Influence of the position of the swash plate rotation axis on the volumetric efficiency of the axial pistons pumps
- Paweł Załuski
2014 Mechines Technologies Materials
The article describes the influence of the position of the swash plate axis of rotation on the size of the dead space and the volumetric efficiency of the axial pistons pump. Superposition of the two motions have been proposed - the rotation of the swash plate with respect to axis intersecting the axis of rotation of the pump shaft and the shifts of swash plate yielding a result of the rotation axis offset effect. In the article it is also made the comparison of the volumetric efficiency of the pump with the axis intersecting with the axis of rotation, and the construction with the shifted axis.
Influence of thermal effects on mechanical properties of PVDF-coated fabric
- Andrzej Ambroziak
- Paweł Kłosowski
2014 JOURNAL OF REINFORCED PLASTICS AND COMPOSITES
This paper describes the method of laboratory tests necessary for identification of temperature influence on mechanical properties of polyvinylidene fluoride-coated polyester fabric often used for tensile structures. Two nonlinear model descriptions are investigated. The first one is based on the piece-wise linear relations between stress and strain and the second one on the Murnaghan model of solid behavior. This paper is proposed as an introduction to the comprehensive investigation on thermal changes of material properties of coated woven fabrics.
Influence of titanium layer on counter electrode on electrical parameters of DSSC
- Wojciech Wachowiak
- Maciej Klein
- Łukasz Skowroński
2014 Zeszyty Naukowe. Elektrotechnika / Uniwersytet Technologiczno-Przyrodniczy
In this paper the influence of the Ti layer thickness at counter-electrode on electrical parameters of DSSCs was examined. The transparent conductive oxide – less (TCO-less) counter electrodes (CE) with titanium layers and platinum as catalyst on Bk7 glass were prepared. Thin metallic films were deposited by means of magnetron sputtering (titanium) and Pulsed Laser Deposition (platinum). The counter electrode with Pt layer on Fluorine doped Tin Oxide (FTO) were used as reference PV cells. The obtained results indicated that the Ti coated cathodes may be used in transparent conductive oxide – less (TCO-less) dye sensitized solar cells as an alternative for Pt/FTO system.
Influence of water salinity on corrosion risk - the case of the southern Baltic Sea coast.
- Krzysztof Żakowski
- Michał Narożny
- Michał Szociński
- Kazimierz Darowicki
2014 Full text ENVIRONMENTAL MONITORING AND ASSESSMENT
Water corrosivity in Gdansk Bay, Poland, the southern part of the Baltic Sea, was investigated. The analysed region is heavily industrialized, and the coastline is very diverse. Twenty-seven test points along the coastline were selected. Water parameters such as salinity, total dissolved solids content, resistivity, conductivity, oxygenation, pH and corrosion rate were determined. The results of the investigation are presented. Water samples were collected, and structural steel specimens were exposed in the water for 2months. The corrosion rate for each test point was determined and plotted on a map. The spatial distribution of water parameters was calculated using the 'inverse distance to a power' method and presented on the maps. Salinity did not exceed 0.7%, and average corrosion rate equalled 0.0585mm/year.
Infrastruktura ładowania pojazdów elektrycznych
- Jarosław Guziński
- Marek Adamowicz
- Jan Kamiński
2014 Automatyka Elektryka Zakłócenia
W artykule przedstawiono przegląd zagadnień z zakresu infrastruktury ładowania pojazdów elektrycznych. Przeanalizowano wpływ dużej liczby pojazdów EV na system elektroenergetyczny. W analizie uwzględniono zarówno wzrastające zapotrzebowanie na moc jak też na zapewnienie wysokiej jakości energii elektrycznej. Pokazano ideę wykorzystania pojazdów EV jako magazynów energii w systemie elektroenergetycznym. Zaprezentowano podstawowe topologie przekształtników energoelektronicznych układów ładowania oraz bardziej zaawansowane struktury do dwukierunkowego przesyłu energii a ponadto struktury układów do ładowania bezprzewodowego.