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Gdańsk University of Technology

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Publications from the year 2014

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  • E-experiments in physics. Proper business process management, collaborative development process and project management guidance – remedy for avoiding the main IT project’s failure
    • Małgotzata A. Płotka
    • Paweł Syty
    • Marta Kwaśnik
    2014 Full text Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Only a few of learning aids and simulations of physical phenomena allow for building interactive experiments; experiments similar to those that should be conducted in physics laboratories at schools. Group of staff from Gdansk University of Technology decided to fill this market niche by designing and constructing a set of virtual experiments – so called e-experiments. To avoid common problems that a lot of IT products brought to failure, they prepared procedures in accordance with the best practices of software and requirement engineering. If requirement specification and development process have been preceded by proper and detailed stakeholders’ identification and characteristic, there is a chance that product will be widely accepted. The paper below describes the process of the e-experiments development with the consideration interests of the target group – young people from e-generation (digital generation) and the teachers.

  • Efekty mechanicznej owalizacji kształtu i wygładzania ziaren elektrokorundu
    • Adam Barylski
    2014 Full text Mechanik

    W artykule przedstawiono wyniki skomputeryzowanej analizy kształtu i wielkości ziaren ściernych przy użyciu specjalistycznego oprogramowania MultiScan v.6.08. Badano efekty mechanicznej owalizacji kształtu ziaren elektrokorundu szlachetnego.

  • EFEKTY NAGNIATANIA GŁADKOŚCIOWEGO STALI W STANIE UTWARDZONYM
    • Piotr Waszczur
    • Michał Dobrzyński
    • Bogdan Ścibiorski
    • Stefan Dzionk
    2014

    Przedstawiono wyniki z badań eksperymentalnych dotyczących procesu nagniatania narzędziem z dociskiem hydrostatycznym. Badania dotyczyły obróbki materiału w stanie utwardzonym po hartowaniu. Skoncentrowano się na ocenie wpływu posuwu i prędkości nagniatania oraz wstępnych wartości parametrów chropowatości powierzchni na stan geometryczny powierzchni opisanej parametrami chropowatości.

  • Efektywność Energetyczna Dolnych Źródeł Instalacji Pomp Ciepłą
    • Tomasz Mania
    • Jakub Doroszkiewicz
    • Rafał Andrzejczyk
    • Tomasz Muszyński
    2014

    Istotnym elementem procesu projektowo-budowlanego stała się umiejętność łączenia różnych tradycyjnych technologii grzewczych z technologiami Odnawialnych Źródeł Energii ze szczególnym uwzględnieniem ciepła odpadowego w różnej formie. W artykule dokonano analizy dolnych źródeł pomp ciepła naturalnych jak i sztucznych.

  • Efektywność filtracji przestrzennej sygnałów w przeciwdziałaniu spoofingowi GPS
    • Jarosław Magiera
    • Ryszard Katulski
    2014 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Przedstawiono metodę przeciwdziałania spoofingowi GPS poprzez formowanie minimum charakterystyki kierunkowej układu antenowego. Opisano metodykę i wyniki badań tłumienia sygnałów niepożądanych w obecności szumu. Zaprezentowano rezultaty statystycznej analizy wpływu filtracji przestrzennej na tłumienie prawdziwych sygnałów GPS. W podsumowaniu wykazano korzyści wynikające z użycia przyjętej metody, w stosunku do innych znanych rozwiązań.

  • Efektywność i skuteczność w koncepcji doboru mierników procesów w startupie biotechnologicznym
    • Bartosz Ogrodowczyk
    2014

    W niniejszej pracy autor przedstawił zagadnienia związane z podejściem procesowym w organizacji z uwzględnieniem rezultatów działań w postaci danych uzyskiwanych z miar efektywności i skuteczności. Przedstawiono definicje pojęć efektywności i skuteczności, a także przegląd koncepcji ich pomiaru w zależności od różnych perspektyw podejścia do tej problematyki. Przeanalizowano ujęcie celowościowe efektywności, dodatkowo skupiono się na podejściu systemowym. Ponadto autor przedstawił syntetyczną charakterystykę systemów jakości specyficznych dla firm z sektora biotechnologicznego wraz z propozycją implementacyjną odpowiednich mierników dla wcześniej zidentyfikowanych procesów. Ze względu na duże znaczenie problematyki jakości w gospodarce rynkowej, efektywność i skuteczność jest rozważana przez autora w ramach systemów zarządzania jakością.

  • Efektywność zmian finansowania szpitali
    • Justyna Kujawska
    2014 Full text PRACE NAUKOWE UNIWERSYTETU EKONOMICZNEGO WE WROCŁAWIU

    Celem artykułu jest przedstawienie oceny efektywności względnej szpitali ogólnych, finansowanych ze środków NFZ, w latach 2007-2010. W roku 2008 nastąpiła zmiana sposobu finansowania szpitali, wynikająca z wdrożenia systemu Jednorodnych Grup Pacjentów (JGP). Do oceny względnej efektywności szpitali finansowanych przez oddziały wojewódzkie NFZ wykorzystano metodę Data Envelopment Analysis (DEA) oraz indeks Malmquist-DEA. Zastosowane modele pozwoliły na ocenę efektywności technicznej i efektywności skali. Dekompozycja indeksu Malmquist-DEA umożliwiła określenie przyczyn zmian produktywności.

  • Effect of Compounding Conditions on Static and Dynamic Mechanical Properties of High Density Polyethylene/Ground Tire Rubber Blends
    • Krzysztof Formela
    • Magdalena Formela
    • Jerzy Korol
    2014 INTERNATIONAL POLYMER PROCESSING

    Searching for new and cost-effective methods of waste rubber recycling is a subject of research in many scientific centers in the world. In this paper there are presented results of the research of the extrusion process of cheap and environmentally friendly thermoplastic compositions containing 50 % wt. of masses of ground tire rubber (GTR). The aim of this study was to determine the relationship between the mixing conditions and properties of obtained products, which is important from a technological point of view. The mixing conditions were determined by using two variables: the screw configuration (co-rotating and counter-rotating) and the type of polyethylene. In the case of both variables, thermoplastic compositions were treated with various shear forces induced by screw speed changes. The influence of mixing conditions on the extrusion process was determined (screw torque, melt flow rate) as well as static and dynamic mechanical properties of obtained materials.

  • Effect of hydroxylated soybean oil and bio-based propanediol on the structure and thermal properties of synthesized bio-polyurethanes
    • Janusz Datta
    • Ewa Głowińska
    2014 INDUSTRIAL CROPS AND PRODUCTS

    The aim of this work was to obtain bio-polyurethanes using synthetic compounds and bio-components, i.e. bio-glycols. Bio-polyurethanes were prepared by means of the prepolymer method. Prepolymers were synthesized from 4,4′-diphenylmethane diisocyanate (MDI) and a polyol mixture containing 75% by weight of commercial polyether and 25% by weight of hydroxylated soybean oils (H2 or H3), the latter being obtained in the reaction with bio-glycol during the hydroxylation process. Bio-components were also used as chain extenders of prepolymer, i.e. bio-based 1,2- or bio-based 1,3-propanediol (1,2bioPDO or 1,3bioPDO). The reaction was catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO). The influence of the content of low molecular chain extenders on the structure and thermomechanical properties of the obtained bio-polyurethanes was investigated. The FTIR analysis demonstrated that different types of bio-propanediol change the chemical structure of the obtained bio-polyether urethanes. The results of thermomechanical analysis showed that the application of 1,2-bio-propanediol as a chain extender was advantageous in comparison to bio-based 1,3-propanediol; the polyurethanes produced with 1,2-bio-propanediol exhibited higher storage modulus and lower loss modulus.

  • Effect of isovalent substitution on microstructure and phase transition of LaNb1−xMxO4 (M=Sb, V or Ta; x=0.05–0.3)
    • Sebastian Lech Wachowski
    • Aleksandra Dorota Mielewczyk-Gryń
    • Maria Gazda
    2014 Full text JOURNAL OF SOLID STATE CHEMISTRY

    LaNb1−xMxO4 oxides with pentavalent elements of different ionic sizes (M=Sb, Ta and V, x=0.05–0.3) were synthesized by the solid state reaction method. Special interest was devoted to the antimony substituted lanthanum niobate which is a new material in this group. Rietveld analysis of the X-ray diffraction patterns was used to determine the influence of the material composition on unit cell parameters. On the basis of dilatometric measurements phase transition temperatures and thermal expansion coefficients of the studied materials were determined. It was shown that with increasing concentration of Sb the phase transition temperature decreases. Thermal expansion coefficient of the antimony substituted samples above the transition temperature is in the range from 8.1 to 9.1×10−6 1/K, whereas below the transition temperature the TEC value is between 14 and 17.3×10−6 1/K. Influence of Ta, V and Sb substitutions on the microstructure and grain size was studied.

  • Effect of long-term cold storage on physicochemical attributes and bioactive components of kiwi fruit cultivars
    • Yong-Seo Park
    • Myang Hee Im
    • Jin-Ho Choi
    • Han-Chan Lee
    • Kyung-Sik Ham
    • Seong-Gook Kang
    • Yong Seo Park
    • Milan Suhaj
    • Jacek Namieśnik
    • Shela Gorinstein
    2014 Full text CyTA-Journal of Food

    Various kiwi fruit cultivars, bred in Korea, were kept in cold storage for 8–24 weeks for possible increase of their quality. Firmness significantly decreased at initial time in all cultivars.The rate of softeningwas the slowest in “Hayward”, followed by “Hort16A”, “Haenam”, “Daheung”, “Bidan”, “Hwamei”, and “SKK 12”. Sensory value increased with decreasing of firmness. Soluble solids content increased with storage time while acidity gradually decreased.Reducing sugar content significantly increased at early stage of storage with decreasing of starch content. Therewas no difference of these indices among cultivars. Respiration rate increased with time and then decreased during cold storage. Peaks time was different between cultivars, therefore we represented trend of respiration changes in all cultivars. All kiwi fruit cultivars showed climacteric patterns in respiration. The rate of softening was closely related to the degree and peak time of ethylene production. The highest shelf life was in “Hayward” and “Hort 16 A” (24weeks) and the lowest in “SKK-12” (8 weeks).All investigated cultivars bred inKorea showedmuch lower shelf life than “Hayward” and “Hort 16 A”. Radical scavenging assays and chemometrical processing were used for the determination of bioactive kiwi fruits’ compounds. Polyphenols in water extractswere the highest in “SKK-12” and the lowest in “Hayward” [16.34±1.11and5.30±0.45mggallicacidequivalents (GAE)/gdryweight (DW)]. The values of β-carotene activities (27.61 ± 2.44%and 8.33 ± 0.74%) and Ferric-reducing/antioxidant power [(FRAP, Trolox equivalent (TE)/ gDW)24.55 ± 2.01 and 7.12 ± 0.41]were the highest in “SKK-12”. The lowest results were estimated in “Hayward”.All kiwi fruit cultivars showed a high level of correlation between the contents of phenolic compounds (polyphenols, tannins, and flavonoids) and their antioxidant values. We presented for thefirst time the results of shelf life of newcultivars bred inKorea and their comparisonwith thewidely studied ones, such as “Hayward” and “Hort 16A”. Cold storage extended shelf life in kiwi fruit without any chilling injury or color change. According to the antioxidant properties of different cultivars, the highest was in “SKK-12” with the lowest shelf life and the lowest was in “Hayward” with the highest shelf life.

  • Effect of microstructure on mechanical properties and corrosion resistance of 2205 duplex stainless steel
    • Jerzy Łabanowski
    • Aleksandra Świerczyńska
    • Santina Topolska
    2014 Full text Polish Maritime Research

    This paper presents results of the research on impact of microstructure of austenitic-ferritic steel of duplex type on its mechanical properties and susceptibility to stress corrosion cracking. As showed, improper processing technologies more and more often used in shipbuilding industry for plates and other half-finished products made of duplex steel may cause significant lowering their properties, which frequently makes their replacing necessary. Results of the tests on stress corrosion under tension with low strain rate (SSRT) conducted in an inert and corrosion (boiling magnesium chloride) environment , are presented. It was proved that even minor structural transformations taking place in 500ºC ageing temperature lower corrosion resistance of the steel. Structural transformations occurring in 700ºC temperature to a smaller extent influence susceptibility to stress corrosion of the steel, however they cause drastic drop in its plasticity.

  • Effect of microstructure on mechanical properties of BA1055 bronze castings
    • Jerzy Łabanowski
    • Tomasz Olkowski
    2014 Full text Archives of Foundry Engineering

    The article presents research results performed on aluminum bronze CuAl10Fe5Ni5 (BA1032) castings used for marine propellers. Metallographic studies were made on light microscope and a scanning electron microscope to assess quantitatively and qualitatively the alloy microstructure. It has been shown that the shape, size and distribution of the iron-rich phase precipitates in bronze microstructure significantly affect its mechanical properties. With an increase in the number of small phase precipitates increases the tensile strength of castings, while the presence of large globular precipitates improves ductility. Fragmentation and shape of phase precipitates depends on many factors, particularly on the chemical composition of the alloy, Fe/Ni ratio, cooling rate and casting technology.

  • Effect of native air-formed oxidation on the corrosion behavior of AA7075 aluminum alloys
    • Jacek Ryl
    • Joanna Wysocka
    • Magdalena Jarzynka
    • Artur Zieliński
    • Juliusz Orlikowski
    • Kazimierz Darowicki
    2014 CORROSION SCIENCE

    The microstructure of aluminum alloys plays a key role in their corrosion resistance. In particular, the presence of intermetallic precipitates differing in the potential from the alloy matrix induces local corrosion. The study presents the effect of native air-formed oxidation on the corrosion behavior of AA 7075 aluminum alloy. Various microscopic and spectroscopic techniques were used to examine the changes occurring in the microstructure and passive layer. Anodic Mg2Si phase undergoes oxidation, which results in magnesium hydroxide being built in the passive layer. EIS analysis revealed an improvement of electrochemical properties as a result of exposure to weather conditions.

  • Effect of power frequency on the stress state of disc actuator
    • Piotr Jankowski
    • Janusz Mindykowski
    • Mirosław Wołoszyn
    2014 INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS

    The paper presents the concept of determinig the optimum frequency of coil supply in inductive-dynamic drive. As a criterion to obtain the sought frequency, the smallest value of reduced stress in the disc was assumed while maintaining the desired dynamics.

  • Effect of power frequency on the stress state of disc actuator
    • Piotr Jankowski
    • Janusz Mindykowski
    • Mirosław Wołoszyn
    2014 INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS

    This paper presents the concept of determining the optimum frequency of coil supply in inductive-dynamic drive. As a criterion to obtain the sought frequency, the smallest value of reduced stress in the disc was assumed while maintaining the desired dynamics. The disc stress is determined on the basis of solution of vibrating thin plate equation. Magnetic pressure acting on the disc is obtained from a hybrid circumferentially-field model (CI-FI).

  • Effect of surface roughness on thermal-hydraulic characteristics of plate heat exchanger
    • Jan Wajs
    • Dariusz Mikielewicz
    2014 Key Engineering Materials

    In the paper the experimental analysis of passive heat transfer intensification in the case of modeled plate heat exchanger is conducted. The plate heat exchanger is chosen for the analysis because this kind of heat exchangers could be prospectively applied in the ORC systems, however other areas or application are equally possible. The experimental setup was assembled at the Department of Energy and Industrial Apparatus of Gdansk University of Technology. The passive intensification was obtained by a modification of the heat transfer surface. The roughness of surface was increased by using of glass particles of 300-400 μm size. During the experiment single-phase convective heat transfer was studied. The experiment was done in two stages. In the first stage the model of commercial plate heat exchanger was investigated, while in the second stage – the identical one but with modified heat transfer surface. Model of heat exchanger consisted of three plates. The direct comparison of thermal and flow characteristics between both devices was possible due to assurance of equivalent conditions at the inlet to the system. The thermal and hydraulic characteristics are presented. The thermal analysis shows that in some range of heat flux the overall heat transfer coefficient was higher for the commercial heat exchanger, while for the other was higher for the heat exchanger with modified surface. The influence of larger roughness on heat transfer cannot unequivocally be evaluated. Therefore as the next step the systematic investigations of model heat exchangers (only with one hot and one cold passage) will be conducted.

  • Effect of the Presence of the Lifting Pocket on The THD Performance of a Large Tilting-Pad Thrust Bearing
    • Michel Fillon
    • Michał Wodtke
    • Michał Wasilczuk
    2014

    In this paper, an attempt was taken to study the effect of the lifting pocket on THD performance of a large tilting-pad thrust bearing of Itaipu power plant. B3earing performance was evaluated including recess shape for several cases of its depth. The results show, that hydrostatic recess changes calculated bearing properties quite significantly, especially in the vicinity of the pocket

  • Effect of Time Varying Measurement Conditions on Antenna Pattern in Near Field Measurement and Its Correction Procedure
    • Mateusz Mazur
    • Wojciech Marynowski
    • Adam Kusiek
    • Włodzimierz Zieniutycz
    2014

    Authors present the procedure of taking into account the changes of electrical parameters of setup due to the time drift of temperature during the procedure of near field measurement. It is proposed to make additional measurements in determined positions of probe are next used the results to introduce corrections terms in measured data. Such approach was verified practically in experimental near field measurement system.

  • Effective method for determining environmental loads on supporting structures for offshore wind turbines
    • Paweł Dymarski
    • Ewelina Ciba
    • Tomasz Marcinkowski
    2014

    This paper presents a description of an effective method for determining loads due to waves, current and wind acting on the supporting structures of the offshore wind turbines. This method is dedicated to the structures consisting of the cylindrical or conical elements as well as (truncates) pyramids of polygon with a large number of sides (8 or more). The presented computational method is based on the Morison equation, which was originally developed only for cylindrically shaped structures. The new algorithm shown here uses the coefficients of inertia and drag forces that were calculated for non- cylindrical shapes. The analysed structure consists of segments which are truncated pyramids on the basis of a hexadecagon. The inertia coefficients, CM, and drag coefficients, CD, were determined using RANSE-CFD calculations. The CFD simulations were performed for a specific range of variation of the period, and for a certain range of amplitudes of the velocity. In addition, the analysis of influence of the surface roughness on the inertia and drag coefficients was performed. In the next step, the computations of sea wave, current and wind load on supporting structure for the fifty-year storm were carried out. The simulations were performed in the time domain and as a result the function of forces distribution along the construction elements was obtained. The most unfavourable distribution of forces will be used, to analyse the strength of the structure, as the design load.