2014 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2014

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A higher order shell element for wave propagation in isotropic shell structures
- Arkadiusz Żak
- Marek Krawczuk
2014
The presents the new multi mode higher order shell element for wave propagation problems in shell structures.
A Human Behaviour Model Agent for Testing of Voluntary Computing Systems
- Mariusz Matuszek
2014
Paper presents a design and performance of a voluntary-based distributed computing system testing agent, implementing a human behaviour model. The agent, nicknamed iRobot, was designed and implemented to enable controlled, large scale testing of core algorithms of Comcute - a new voluntary distributed computing platform complementary to BOINC. The main agent design goals were: emulation of human behaviour when browsing web pages, flexibility of configuration, ease of use and ability to run multiple agent instances on a single host.
A Linear Phase Filter in Quadruplet Topology With Frequency-Dependent Couplings
- Łukasz Szydłowski
- Natalia Leszczynska
- Michał Mrozowski
2014 IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS
This letter presents a design of a linear phase microwave bandpass filter. The filter is composed of four resonators arranged in the quadruplet topology. Making the cross and one direct coupling dispersive gives additional design flexibility. The first advantage of using frequency-dependent couplings is the possibility to chose an arbitrary location of a pair of complex transmission zeros (TZs) in the s-domain. The second one is the presence of an additional imaginary transmission zero that improves the filter selectivity. We provide a proof-of-concept design of a filter using substrate integrated waveguide (SIW) technology. The frequency-dependent couplings are implemented in SIW as a composition of both: an inductive part realized in a form of an H-plane iris and a capacitive part realized as a grounded coplanar waveguide (GCPW). The measured filter characteristics prove the validity of the model.
A LUMPED-CIRCUIT MODEL OF CIRCULAR PISTON TRANSDUCER FOR MODELING ITS PERFORMANCE IN DUAL FREQUENCY OPERATING MODES
- Marek Moszyński
2014
The paper presents novel network equivalent circuit of piezoceramic circular disc transducer that takes into account thickness and ra dial mode of vibrations. The starting point of the analysis is 4-port description of circular disc element representing the solution of wave equation set in radial and thickness directions. Th e approximate solution for harmonic case is represented in the form of 4x4 matrix, which is syn thesized and implemented in circuit analysis software. The network is extended with acoustical p ort that allows for pressure calculations in the similar manner as when measuring echo-sounder trans mitting and receiving parameters. The novel model uses Cauer LC ladder of the second form for implementation of radial part of vibrations. The values for its parameters are ob tained by expanding the quotient of zero and first order Bessel functions of the first kind into continued fraction representation and can be expressed directly by geometry of the piezoelectric disc (its radius and thickness) and its material properties (stiffness coefficient and density). As the ladder contains only lumped elements, the model is portable across different implementations of SPICE simulators. It has clear interpretation considering mechanical properties of vibrating disc when comparing to thickness vibration model. Presented equivalent circuit of wh ole transducer is especially useful for simulating complete electronic circuit of dual freq uency echo-sounders constructed using single circular disc transducer.
A mathematical model of rheological behavior of novel bio-based isocyanate-terminated polyurethane prepolymers
- Ewa Głowińska
- Janusz Datta
2014 INDUSTRIAL CROPS AND PRODUCTS
In this paper, the results of rheological study on isocyanate-terminated polyurethane prepolymers, containing modified soybean oil residues incorporated into the chemical structure are described. Isocyanate-terminated prepolymers were synthesized from 4,4′-diphenylmethane diisocyanate and the mixture of hydroxylated soybean oil and commercial polyether. The measurements were performed by using rotary rheometer R/S-CPS+ (Brookfield, USA), while the rheological parameters were calculated by using Rheo3000 program. Based on rheological measurements, the viscosity curves and flow curves for prepolymers in the temperature range from 50 to 70 °C were plotted. Prepolymer samples were tested with controlled shear rate (CSR). It was found that a viscosity of bio-based isocyanate-terminated prepolymers decreases with increasing content of hydroxylated soybean oil in the polyol mixture. The rheological data for bio-based polyurethane prepolymers were also mathematically modeled. It was found that the synthesized prepolymers are non-Newtonian fluids that can be described by Ostwald-de Waele and Herschel Bulkley functions as optimal individual models. The conducted investigations showed that the dynamic viscosity and rheological behavior of bioprepolymers samples could depend on the amount of hydroxylated soybean oil used in the polyol mixture.
A Measurement-Based Approach for Speed Control of Induction Machines
- Mohamed Amine Fnaiech
- Sofiane Khadraoui
- Hazem N. Nounou
- Mohamed N. Nounou
- Jarosław Guziński
- Haitham Abu-Rub
- Aniruddha Datta
- Shankar P. Bhattacharyya
2014 IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
This paper presents an approach to design a measurement-based controller for induction machines. The proposed control approach is motivated by the fact that developing an appropriate mechanical model of such induction machines is a challenging task. Since our proposed control methodology is only on the basis of measured data, the controller design does not require any information about the model of the mechanical part. The control of motor drive is often based on sensorless fieldoriented control techniques because of their advantages such as noise and cost reductions and high reliability. Hence, we assume here that measurements used for the controller design are collected using an estimator based on the electrical equations of the induction machine. A practical application to control the speed of an induction machine is presented to validate and demonstrate the efficiency of the proposed method.
A Method and Device for 3D Recognition of Cutting Edge Micro Geometry
- Bartosz Pałubicki
- Michał Szulc
- Jakub Sandak
- Gerhard Sinn
- Kazimierz Orłowski
2014 Pełny tekst Drvna Industrija
A very useful method was successfully applied in the investigation of tools for machining wood and wood based composites. It allows scanning of the cutting edge micro geometry in three dimensions and reproducing it in a virtual space as a 3D surface. The application of the method opens new possibilities of studying tool wear by scanning, including the calculation of volume loss and other analysis of tool wedge geometry along and perpendicularly to the cutting edge. Effectiveness of the method and scanner were successfully verified by a reference ESEM (Environmental Scanning Electron Microscopy) method.
A Method of Assessment of the Liquid Sloshing Impact on Ship Transverse Stability
- Przemysław Krata
2014 Pełny tekst TransNav - The International Journal on Marine Navigation and Safety of Sea Transportation
Liquid sloshing phenomenon taking place in partly filled ships? tanks directly affects the stability of a vessel. However, only static calculations are carried out onboard ships nowadays and static transfer of liquid weight is taken into account in the course of routine stability calculation. The paper is focused on a dynamic heeling moment due to liquid sloshing in tanks onboard ships. The set of numerical simulations of liquid sloshing taking place in moving tanks is carried out. The realistic range of geometric parameters is taken into account. The conducted CFD simulations are experimentally verified. Finally, the method of an assessment of the liquid sloshing impact on ship transverse stability is worked out. The key point of the method is a dynamic coefficient describing relation of the researched dynamic heeling moment and the quasi-static one in terms of dynamic stability of a vessel which is related to the weather criterion of ship stability assessment.
A MODEL FOR FORECASTING PM10 LEVELS WITH THE USE OF ARTIFICIAL NEURAL NETWORKS
- Arkadiusz Sarzyński
- Cezary Orłowski
2014 Pełny tekst
This work presents a method of forecasting the level of PM10 with the use of artificial neural networks. Current level of particulate matter and meteorological data was taken into account in the construction of the model (checked the correlation of each variable and the future level of PM10), and unidirectional networks were used to implement it due to their ease of learning. Then, the configuration of the network (built on the basis of the developed model) was established, defining the number of layers and neurons, as well as the activation function. 4 methods of propagation (Back Propagation, Resilient Propagation, Manhattan Propagation and Scaled Conjugate Gradient) were applied in the network learning process to select the best method. The obtained results were then compared with real values and the complete network configuration (minimizing the forecast error) was determined. After completion of the learning process, the developed network was used to forecast the particulate matter levels in Gdansk.
A Model-Based Improved Control of Dissolved Oxygen Concentration in Sequencing Wastewater Batch Reactor
- Karol Błaszkiewicz
- Robert Piotrowski
- Kazimierz Duzinkiewicz
2014 Pełny tekst Studies in Informatics and Control
Biochemical processes at wastewater treatment plant are complex, nonlinear, time varying and multivariable. Moreover, relationships between processes are very strong. One of the most important issues is exerting proper control over dissolved oxygen levels during nitrification phase. This parameter has a very large impact on activity of microorganisms in activated sludge and on quality of pollution removal processes. Oxygen is supplied by aeration system which consists of many nonlinear elements (blowers, pipes, diffusers). In this paper, the sequencing batch reactor is applied and modelled. Also, the aeration system is modelled. Those models are validated based on real data sets. The adaptive control system with anti-windup filter is proposed and designed for tracking the reference trajectory of dissolved oxygen. Furthermore, the reference trajectory of dissolved oxygen is generated by the supervisory controller using NH4 measurements. Simulation results of control system are calculated for a case study plant located in Swarzewo, Northern Poland.
A Model-Driven Solution for Development of Multimedia Stream Processing Applications
- Anna Bobkowska
- Michał Nykiel
- Jerzy Proficz
2014
This paper presents results of action research related to model-driven solutions in the area of multimedia stream processing. The practical problem to be solved was the need to support application developers who make their multimedia stream processing applications in a supercomputer environment. The solution consists of a domain-specific visual language for composing complex services from simple services called Multimedia Stream Processing Modeling Language (MSP-ML) and a tool integrated with the supercomputer environment which makes round-trip transformations between models and executable service structures. The contribution to the debate about optimal model-driven technology can be stated as follows. Effective application of modeling requires model-driven solutions characterized by a high level of integration of models and tools in their context of use including user goals and activities as well as target environment. Such solutions sometimes require combination of several available approaches, i.e. domain-specific modeling, use of standards and modeling tools embedded in the platform.
A New Double Digestion Ligation Mediated Suppression PCR Method for Simultaneous Bacteria DNA-Typing and Confirmation of Species: An Acinetobacter sp. Model
- Karolina Stojowska
- Beata Krawczyk
2014 Pełny tekst PLOS ONE
We have designed a new ddLMS PCR (double digestion Ligation Mediated Suppression PCR) method based on restriction site polymorphism upstream from the specific target sequence for the simultaneous identification and differentiation of bacterial strains. The ddLMS PCR combines a simple PCR used for species or genus identification and the LM PCR strategy for strain differentiation. The bacterial identification is confirmed in the form of the PCR product(s), while the length of the PCR product makes it possible to differentiate between bacterial strains. If there is a single copy of the target sequence within genomic DNA, one specific PCR product is created (simplex ddLMS PCR), whereas for multiple copies of the gene the fingerprinting patterns can be obtained (multiplex ddLMS PCR). The described ddLMS PCR method is designed for rapid and specific strain differentiation in medical and microbiological studies. In comparison to other LM PCR it has substantial advantages: enables specific species’ DNA-typing without the need for pure bacterial culture selection, is not sensitive to contamination with other cells or genomic DNA, and gives univocal ‘‘band-based’’ results, which are easy to interpret. The utility of ddLMS PCR was shown for Acinetobacter calcoaceticus-baumannii (Acb) complex, the genetically closely related and phenotypically similar species and also important nosocomial pathogens, for which currently, there are no recommended methods for screening, typing and identification. In this article two models are proposed: 3' recA -ddLMS PCR-MaeII/RsaI for Acb complex interspecific typing and 5' rrn-ddLMS PCR-HindIII/ ApaI for Acinetobacter baumannii intraspecific typing. ddLMS PCR allows not only for DNA-typing but also for confirmation of species in one reaction. Also, practical guidelines for designing a diagnostic test based on ddLMS PCR for genotyping different species of bacteria are provided.
A new human IgG avidity test, using mixtures of recombinant antigens (rROP1, rSAG2, rGRA6), for the diagnosis of difficult-to-identify phases of toxoplasmosis
- Dorota Drapała
- Lucyna Holec-Gąsior
- Józef Kur
- Bartłomiej Ferra
- Elżbieta Hiszczyńska-Sawicka
- Dariusz Lautenbach
2014 DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE
The preliminary diagnostic utility of two mixtures of Toxoplasma gondii recombinant antigens (rROP1+rSAG2 and rROP1+rGRA6) in IgG ELISA and IgG avidity test has been evaluated. A total of 173 serum samples from patients with toxoplasmosis and seronegative people were examined. The sensitivity of IgG ELISA for rROP1+rSAG2 and rROP1+rGRA6 was 91.1% and 76.7%, respectively, while the reactivity for sera from patients where acute toxoplasmosis was suspected was higher, at 100% and 95.4%, respectively, than for people with chronic infection, at 88.2% and 70.6%. In this study a different trend in avidity maturation of IgG antibodies for two mixtures of proteins in comparison with native antigen was observed. The results suggest that a new IgG avidity test using the mixtures of recombinant antigens may be useful for the diagnosis of difficult-to-identify phases of toxoplasmosis. For this reason, selected mixtures after the additional tests on groups of sera with well-defined dates of infection could be used as a better alternative to the native antigens of the parasite in the serodiagnosis of human T. gondii infection.
A New Microwave Ceramic – Polymer Composite with 0-3 Connectivity
- Dionizy Czekaj
- Joanna Micior
- Agata Lisińska-Czekaj
2014 Pełny tekst ARCHIVES OF METALLURGY AND MATERIALS
Goal of the present research was to fabricate and study two-phase BiNbO4//PVDF composites with 0-3 connectivity. Such composite consists of there-dimensionally connected polymer matrix loaded with dielectric ceramic particles. In the present case BiNbO4 powder acted as an active phase (dispersed phase) whereas polyvinylidene fluoride (PVDF) acted as a non-active (passive) phase (matrix). BiNbO4//PVDF composites with the volume fraction of the ceramic phase cV =2, 4, 6, 8, 10, 16 and 20 vol. % were prepared. Average grain size of BiNbO4 powder was <d>=1.86 m. It was found that BiNbO4 powder exhibited orthorhombic symmetry with Pnna (52) space group and PVDF polymer powder was -phase. Minimum of dielectric losses at room temperature were found within the frequency range =103-104 Hz. It was found that composite with cV =10% of ceramic powder exhibited lower values of dielectric permittivity.
A NEW WORK SAFETY MANAGEMENT SYSTEM IN CONSTRUCTION SITES
- Tomasz Gardzioła
2014 Pełny tekst Zeszyty Naukowe Politechniki Poznańskiej. Organizacja i Zarządzanie
The hazards on the list are assessed on two levels, namely as minor and serious, and the risk relating to work at the site at three levels: small, average and high, within the range from 1 to 10, where 1 is the lowest value meaning a small risk, and 10 the value meaning a high risk.
A Note on a Problem Posed by D. E. Knuth on a Satisfiability Recurrence
- Philippe Jacquet
- Charles Knessel
- Wojciech Szpankowski
2014 COMBINATORICS PROBABILITY & COMPUTING
We resolve a conjecture proposed by D.E. Knuth concerning a recurrence arising in the satisfiability problem. Knuth's recurrence resembles recurrences arising in the analysis of tries, in particular PATRICIA tries, and asymmetric leader election. We solve Knuth's recurrence exactly and asymptotically, using analytic techniques such as the Mellin transform and analytic depoissonization.
A note on an approximative scheme of finding almost homoclinic solutions for Newtonian systems
- Robert Krawczyk
2014 Pełny tekst BANACH CENTER PUBLICATIONS
In this work we will be concerned with the existence of an almost homoclinic solution for a perturbed Newtonian system in a finite dimensional space. It is assumed that a potential is C^1 smooth and its gradient is bounded with respect to a time variable. Moreover, a forcing term is continuous, bounded and squere integrable. We will show that the appproximative scheme due to J. Janczewska for a time periodic potential extends to our case.
A NOTE ON ON-LINE RAMSEY NUMBERS FOR QUADRILATERALS
- Joanna Cyman
- Tomasz Dzido
2014 Pełny tekst Opuscula Mathematica
We consider on-line Ramsey numbers defined by a game played between two players, Builder and Painter. In each round Builder draws an the edge and Painter colors it either red or blue, as it appears. Builder’s goal is to force Painter to create a monochromatic copy of a fixed graph H in as few rounds as possible. The minimum number of rounds (assuming both players play perfectly) is the on-line Ramsey number \widetilde{r}(H) of the graph H. An asymmetric version of the on-line Ramsey numbers \widetilde{r}(G,H) is defined accordingly. In 2005, Kurek and Ruciński computed \widetilde{r}(C3). In this paper, we compute \widetilde{r}(C4,Ck) for 3≤k≤7. Most of the results are based on computer algorithms but we obtain the exact value \widetilde{r}(C4) and do so without the help of computer algorithms.
A novel cold-active β-D-galactosidase with transglycosylation activity from the Antarctic Arthrobacter sp. 32cB - gene cloning, purification and characterization
- Anna Pawlak-Szukalska
- Marta Wanarska
- Arkadiusz Popinigis
- Józef Kur
2014 Pełny tekst PROCESS BIOCHEMISTRY
A gene encoding a novel β-D-galactosidase from the psychrotolerant Antarctic bacterium Arthrobacter sp. 32cB was isolated, cloned and expressed in Escherichia coli. The active form of recombinant β-D-galactosidase consists of two subunits with a combined molecular weight of approximately 257 kDa. The enzyme's maximum activity towards o-nitrophenyl-β-D-galactopyranoside was determined as occurring at 28 °C and pH 8.0. However, it exhibited 42% of maximum activity at 10 °C and was capable of hydrolyzing both lactose and o-nitophenyl-β-D-galactopyranoside at that temperature, with Km values of 1.52 and 16.56 mM, and kcat values 30.55 and 31.84 s−1, respectively. Two units of the enzyme hydrolyzed 90% of the lactose in 1 mL of milk at 10 °C in 24 h. The transglycosylation activity of Arthrobacter sp. 32cB β-D-galactosidase was also examined. It synthesized galactooligosaccharides in a temperature range from 10 to 30 °C. Moreover, it catalyzed the synthesis of heterooligosaccharides such as lactulose, galactosyl-xylose and galactosyl-arabinose, alkyl glycosides, and glycosylated salicin from lactose and the appropriate acceptor at 30 °C. The properties of Arthrobacter sp. 32cB β-D-galactosidase make it a candidate for use in the industrial removal of lactose from milk and a promising tool for the glycosylation of various acceptors, especially those which are thermosensitive.
A numerical model to simulate the motion of a lifesaving module during its launching from the ship’s stern ramp
- Paweł Dymarski
- Czesław Dymarski
2014 Pełny tekst Polish Maritime Research
The article presents a numerical model of object motion in six degrees of freedom (DoF) which is intended to be used to simulate 3D motion of a lifesaving module during its launching from a ship using a stern ramp in rough sea. The model, of relatively high complexity, takes into account both the motion of the ship on water in changing sea conditions, and the relative motion of the ramp with respect to the ship. The motion of the ramp changes and strongly depends on its constructional and geometrical parameters. The presented model takes into account the displacement of the submerged part of the ramp, as well as its damping in the water and the interaction with the module moving on it. The results of test simulation of a module launching from the ship in still water are included.