2016 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2016

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Experimental investigation of Steel–Concrete–Polymer composite barrier for the ship internal tank construction
- Karol Niklas
- Janusz Kozak
2016 OCEAN ENGINEERING
Transportation of dangerous cargo by ships demands ensuring an appropriate protection level in case of an accident. Two of the most dangerous accident types resulting in an oil spill are grounding and ship to ship collision. The article presents results of research on a new composite construction for a ship hull that increases structural safety during collision. The concept of semi-elastic Steel–Concrete–Polymer structure is presented. The most important results of the research are discussed. The resistance to collision and grounding of the new sandwich solution is investigated by means of two independent large scale experiments. The first collision experiment was conducted on a reference ship section representative for a double bottom or a double side of a ship. The second test was performed on a construction similar to the first one, but with an additional semi-elastic protective barrier. Both ship sections were loaded in the same manner by a sphere-shaped intender simulating the assumed collision scenari. On the basis of large-scale collision experiments the new solution of semi-elastic protective barrier was proven to significantly increase resistance to collision and grounding.
Experimental investigations of fracture process in concrete by means of x-ray micro-computed tomography
- Łukasz Skarżyński
- Andrzej Tejchman-Konarzewski
2016 Pełny tekst STRAIN
W artykule pokazano doświadczalne wyniki badań procesu pękania w betonie stosując mikro-tomografię. Doświadczenia wykonano dla zginanych belek betonowych. Wyniki doświadczalne modelowano stosując MES na bazie modelu z degradacją sztywności sprężystej z nielokalnym osłabieniem. Beton symulowano jako materiał 4-fazowy. Uzyskano dobra zgodność wyników MES z doświadczeniami.
Experimental research on water lubricated marine stern tube bearings in conditions of improper lubrication and cooling causing rapid bush wear
- Wojciech Litwin
- Czesław Dymarski
2016 Pełny tekst TRIBOLOGY INTERNATIONAL
Water lubricated bearings are popular in sliding bearings of marine propeller shafts, turbines and pump shafts. Such popularity is partly due to their simple construction which also means a relatively affordable price. In practical experience one may also observe cases of rapid wear or even malfunctions of this bearings, some of which may be caused by insufficient flow of lubricant leading to overheating. The conducted research determined that certain bearings continue to work properly despite lack of lubricant flow and cooling. This is due to low motion resistance levels resulting low friction so heat generated in the friction zone of such bearings is sufficiently low to be dispersed into surroundings once bearing temperature rises and stabilizes at a safe level.
Experimental results of full scattering profile from finger tissue-like phantom
- Idit Feder
- Maciej Wróbel
- Hamootal Duadi
- Małgorzata Szczerska
- Dror Fixler
2016 Pełny tekst Biomedical Optics Express
Human tissue is one of the most complex optical media since it is turbid and nonhomogeneous. We suggest a new optical method for sensing physiological tissue state, based on the collection of the ejected light at all exit angles, to receive the full scattering profile. We built a unique set-up for noninvasive encircled measurement. We use a laser, a photodetector and finger tissues-mimicking phantoms presenting different optical properties. Our method reveals an isobaric point, which is independent of the optical properties. We compared the new finger tissues-like phantoms to others samples and found the linear dependence between the isobaric point's angle and the exact tissue geometry. These findings can be useful for biomedical applications such as non-invasive and simple diagnostic of the fingertip joint, ear lobe and pinched tissues.
Experimental study of the post tensioned prestressed concrete corbels
- Małgorzata Lachowicz
- Krystyna Nagrodzka-Godycka
2016 ENGINEERING STRUCTURES
The results of experimental investigation of 6 symmetrical double prestressed corbels of variable shear span to depth ratio and variable location of prestressing bars are presented in the paper. The post ten- sioned corbels were prestressed with Macalloy 1030 bars of 25 mm in diameter. The results of the tests were compared with the cracking and load carrying capacity of corbels reinforced with passive reinforce- ment. As a result of the analysis, a formula of calculation of force causing the inclined crack in the central area of the corbel was proposed. Usability of the selected computational schemes applying the truss mod- els, as well as the shear–friction hypotheses, were assessed
Experimental test results of the 150kVA 18-pulse diode rectifier with series active power filter
- Piotr Mysiak
- Wojciech Śleszyński
- Artur Cichowski
2016
The paper presents the control system and selected results of experimental tests of the ac/dc power converter consisting of 18-pulse diode rectifier on the basis of coupled reactors and a serial active power filter. Three configurations of the 150kVA converter were tested experimentally and compared: 18-pulse diode rectifier with and without additional grid reactor and the rectifier integrated with the active power filter. The applied control method of active filter significantly reduces the grid current harmonic distortion and unbalance, which is particularly advantageous at low loads and non-ideal supply voltage.
Experimental tests and numerical simulations of full scale composite sandwich segment of a foot- and cycle- bridge
- Mikołaj Miśkiewicz
- Karol Daszkiewicz
- Tomasz Ferenc
- Wojciech Witkowski
- Jacek Chróścielewski
2016
In the paper experimental tests and numerical simulations of a full cross-section segment of ultimately designed foot-and cycle-bridge are presented. The experimental tests were conducted on element with length reduced to 3 m and unchanged (target) cross-section dimensions. The external skin of structure is GFRP laminate while internal core is PET foam. Several quasi-static tests were performed using hydraulic cylinder to generate vertical loads, and using specially designed system of rods to generate horizontal loads applied to the structure transversally and longitudinally. Results of the numerical simulations conducted in the FEM environment are shown and serve as the basis for the design process of target foot-and cycle- bridge.
Experimental tests for the determination of mechanical properties of PVC foil
- Andrzej Ambroziak
2016
The paper presents an application of the PVC film in civil engineering. Mechanical behaviour of the PVC film applied for suspended ceilings, in the form of a stretch ceiling is investigated under uniaxial and biaxial tensile tests. The study is focused on the determination of mechanical properties from experimental data (uniaxial and biaxial tensile tests). The uniaxial cyclic tests are performed in order to observe a variation of immediate mechanical properties under cyclic load. This paper is suggested to be an introduction to a comprehensive in-vestigation on building engineering application of the PVC foils
Experimental validation of the rolling resistance measurement method including updated draft standard
- Fabienne Anfosso-Ledee
- Véronique Cerezo
- Rune Karlsson
- Anneleen Bergiers
- Sylvie Dauvergne
- Jerzy Ejsmont
- Luc Goubert
- Hugo Lesdos
- Johan Maeck
- Ulf Sandberg
- Leif Sjogren
- Marek ZöLLER
2016
The main objective of ROSANNE is the harmonisation and standardisation of the measurement of skid resistance, noise emission and rolling resistance of road pavements. Regarding rolling resistance characterisation, a draft for standardization of a harmonized procedure for classification of road surfaces across Europe has been prepared within WP3 (deliverable 3.5). The procedure deals with the direct measurement on real roads of the rolling resistance coefficient of a free‐rolling test tyre, mounted on a towed trailer or a self‐propelled vehicle. In order to assess the proposed procedure, an experimental validation was organized in September 2015, and performed as a “Round Robin Test” (RRT) in which 5 test trailers were compared when using the draft standard method. The test program was implemented in Nantes (France), taking benefit of the IFSTTAR’s reference test track, an outdoor facility offering 12 different road surfaces of various texture characteristics, that can be tested in laboratory conditions (no traffic disturbance, road sections in ideal maintenance, a great number of data available). It was completed by tests on a trafficked road circuit in the vicinity, in order to check the applicability of the procedure in realistic road conditions, and its sensitivity to road characteristics not available on the test track (unevenness, slopes). Furthermore, trailer‐based direct measurements of rolling resistance coefficients were compared with alternative indirect measurement methods: coast‐down method and measurements of fuel consumption. The report describes the experimental test programme and provides the results and the analysis of the RRT. The results showed that the proposed methodology is clear enough to be applied without ambiguity. This explains why the correlation between rolling resistance and different surface descriptors varied in quality. However the progress made in a better control of measurement quality is real since previous projects. The correlation between rolling resistance and the MPD texture descriptor and the megatexture indicator LMe is generally good and can be improved by using filtering procedures to calculate the texture profile enveloped by the tyre. The huge amount of data collected during the experiment will be of interest for further developments far beyond the ROSANNE project. The energy‐method showed surprisingly good comparability to the coast‐downs tests and the method seems promising.
Experimental verification of a new method of loop resistance testing in low voltage systems with residual current devices
- Stanisław Czapp
- Kornel Borowski
2016
A periodical verification of the effectiveness of protection against electric shock shall be performed in low voltage systems. The scope of this verification includes loop impedance/resistance testing. If a residual current device is installed in a tested circuit, this testing is problematic. A residual current device trips out during the test, because of the high value of measurement current. This precludes the execution of the test. In the paper a new method of loop resistance testing in low voltage systems is presented. Experimental verification of this method has proved that it enables performing the evaluation of the effectiveness of protection against electric shock without nuisance tripping of residual current devices. The advantage of this method is the high value of the measurement current – many times higher than the rated residual operating current of commonly used residual current devices. It is very important in terms of measurement accuracy.
Exploring efficiency differentials between Italian and Polish universities, 2001-2011
- Tommaso Agasisti
- Joanna Wolszczak-Derlacz
2016 Pełny tekst Science and Public Policy
In this study, data envelopment analysis (DEA) is used to evaluate the relative efficiency of a sample of 54 Italian and 30 Polish state universities over the period 2001–11. The investigation was conducted in two steps. Unbiased DEA efficiency scores were first estimated and then regressed on external variables to quantitatively assess the direction and size of the impact of potential determinants. The analysis reveals a strong heterogeneity in the efficiency scores for each country, which is more pronounced than the difference in average efficiency scores between them. There is evidence that efficiency is determined by the structure of a university’s revenues and academic staff: competitive versus non-competitive resources, and the number of professors. The study also explores the variation in the efficiency and productivity over time. While changes in pure efficiency were similar between the two countries, the efficiency frontier improved more in Italy than in Poland.
Exploring ontological approach for user requirements elicitation in design of online virtual agents
- Katarzyna Ossowska
- Liliana Szewc
- Paweł Weichbroth
- Igor Garnik
- Marcin Sikorski
2016
Effective user requirements elicitation is a key factor for the success of software development projects. There are many qualitative and quantitative research studies that promulgate particular methods and show the application of user requirements elicitation in particular domains. However, few try to eliminate the burden of ambiguity in gathered data, naturally occurring in different groups of stakeholders. This paper deals with this problem by introducing an ontology-based approach which by design provides a shared and common understanding of a domain. On the other hand, the developed ontology is a feasible communication facility for the stakeholders involved, acknowledged and controlled by a group of experts.
Expression of a GDSL esterase from Pseudomonas sp. S9 in Pichiapastoris
- Monika Wicka-Grochocka
- Hubert Cieśliński
- Ewelina Krajewska
- Natalia Filipowicz
- Marta Wanarska
- Józef Kur
2016 New Biotechnology
Cold active lipolytic enzymes are promising to replace the conventional enzymes processes of biotechnological industries. One of the most important feature of the cold-active lipases and esterases is that they offer economic benefits through energy saving. In general, they exhibit high activity at low temperatures and low thermostability at moderate temperatures. Lipolytic enzyme EstS9 was isolated from Pseudomonas sp. S9. A multiple sequence alignment identified EstS9 as belonging to clade II of the GDSL esterase family. The nucleotide sequence of the estS9 gene of Pseudomonas sp. S9 consists of 1,911 bp. The gene encodes for a protein of 636 amino acid residues with a molecular mass of ∼68.0 kDa. The enzyme is tolerant to alkaline pH and effective at medium to low temperatures (40–25 °C). In our previous study [1], the gene estS9 was expressed using pBAD system in E. coli TOP10 cells as His-tagged fusion protein. Like many other recombinant proteins, EstS9 was produced in E. coli in inclusion bodies. For these reason, there is interest in obtaining the extracellular active esterase which can be used for number of industrial application such as additives for laundry detergents. Therefore, during this study we constructed several recombinant P. pastoris designed for this purpose. Currently, these strains are tested for their ability to produce to the culture medium the active and soluble EstS9 esterase.
Extending transition curve in analytical design method
- Władysław Koc
2016 Pełny tekst Przegląd Komunikacyjny
The paper presents the problem of extending the transitional curves, using for this purpose an analytical design method. The basis for the analysis of numerical calculations were carried out for a wide set of parameters characterizing the standard geometric system. We considered an importance of the size of radius of the circular arc and return angle of route on the obtained results after the formulation of appropriate theoretical dependence. It was found that the extension of the transition curve does not need cause large lateral displacements of the existing track at considerable length. It is only necessary to reduce the radius of the circular arc in a suitable way.
Extraction and evaluation of gas-flow-dependent features from dynamic measurements of gas sensors array
- Paweł Kalinowski
- Łukasz Woźniak
- Grzegorz Jasiński
- Piotr Jasiński
2016
Gas analyzers based on gas sensors are the devices which enable recognition of various kinds of volatile compounds. They have continuously been developed and investigated for over three decades, however there are still limitations which slow down the implementation of those devices in many applications. For example, the main drawbacks are the lack of selectivity, sensitivity and long term stability of those devices caused by the drift of the sensors. This implies the necessity of investigations not only in the field of development of gas sensors construction, but also the development of measurement procedures or methods of analysis of sensor responses which compensate the limitations of sensors devices. One of the fields of investigations covers the dynamic measurements of sensors or sensor-arrays response with the utilization of flow modulation techni ques. Different gas delivery patterns enable the possibility of extraction of unique features which improves the stability and selectivity of gas detecting systems. In this article an overview of three utilized flow modulation techniques is presented, together with the propos ition of the evaluation method of their usefulness and robustness in environmental pollutants detecting systems. The preliminary results of dynamic measurements of an commercially available TGS sensor array in the presence of nitrogen dioxide and ammonia are shown.
Extraction of information from born-digital PDF documents for reproducible research
- Bogdan Wiszniewski
- Jacek Siciarek
2016 Pełny tekst Journal of Advanced Management
Born-digital PDF electronic documents might reasonably be expected to preserve useful data units of their source originals that suffice to produce executable papers for reproducible research. Unfortunately, developers of authoring tools may adopt arbitrary PDF generation strategies, producing a plethora of internal data representations. Such common information units as text paragraphs, tables, function graphs and flow diagrams, may require numerous heuristics to handle properly each vendor specific PDF file content. We propose a generic Reverse MVC interpretation pattern that enables to cope with that arbitrariness in a systematic way. It constitutes a component of a larger framework we have been developing for making executable papers out of PDF documents without injecting in the PDF file any extra data or code
Extraction of stable foreground image regions for unattended luggage detection
- Grzegorz Szwoch
2016 Pełny tekst MULTIMEDIA TOOLS AND APPLICATIONS
A novel approach to detection of stationary objects in the video stream is presented. Stationary objects are these separated from the static background, but remaining motionless for a prolonged time. Extraction of stationary objects from images is useful in automatic detection of unattended luggage. The proposed algorithm is based on detection of image regions containing foreground image pixels having stable values in time and checking their correspondence with the detected moving objects. In the first stage of the algorithm, stability of individual pixels belonging to moving objects is tested using a model constructed from vectors. Next, clusters of pixels with stable color and brightness are extracted from the image and related to contours of the detected moving objects. This way, stationary (previously moving) objects are detected. False contours of objects removed from the background are also found and discarded from the analysis. The results of the algorithm may be analyzed further by the classifier, separating luggage from other objects, and the decision system for unattended luggage detection. The main focus of the paper is on the algorithm for extraction of stable image regions. However, a complete framework for unattended luggage detection is also presented in order to show that the proposed approach provides data for successful event detection. The results of experiments in which the proposed algorithm was validated using both standard datasets and video recordings from a real airport security system are presented and discussed.
Eye-tracking Web Usability Research
- Paweł Weichbroth
- Krzysztof Redlarski
- Igor Garnik
2016
In this paper we present the results of a study that aims to evaluate the usability of three selected web services, based on eye–tracking and thinking aloud techniques. The gathered comments and observations, recapitulated and supported by particular measures, allow us to discover and describe typical user behavior pertaining to given tasks to solve.
Fabrication and characterization of boron-doped nanocrystalline diamond-coated MEMS probes
- Robert Bogdanowicz
- Michał Sobaszek
- Mateusz Ficek
- Daniel Kopiec
- Magdalena Moczała
- Karolina Orłowska
- Miroslaw Sawczak
- Teodor Gotszalk
2016 Pełny tekst APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
Fabrication processes of thin boron-doped nanocrystalline diamond (B-NCD) films on silicon-based micro- and nano-electromechanical structures have been investigated. Nanocrystalline boron doped -diamond (B-NCD) films were deposited using Microwave Plasma Assisted Chemical Vapour Deposition (MW PA CVD) method. The variation of B-NCD morphology, structure and optical parameters were particularly investigated. The use of truncated cone-shaped substrate holder enabled to grow thin fully encapsulated nanocrystalline B-NCD with a thickness of approx. 60 nm and RMS roughness of 17 nm. Raman spectra present the typical boron-doped nanocrystalline diamond line recorded at 1148 cm-1. Moreover, the change of mechanical parameters of silicon cantilevers over-coated with boron-doped diamond films was investigated with laser vibrometer. The increase of resonance to frequency of over-coated cantilever is attributed to the change of spring constant caused by B-NCD coating. Topography and electrical parameters of boron-doped diamond films were investigated by tapping mode AFM and electrical mode of AFM – Kelvin probe force microscopy (KPFM). The crystallites-grain size was recorded at 153 nm and 238 nm for boron-doped film and undoped respectively. Based on the contact potential difference data from the KPFM measurements, the work function of diamond layers were estimated. For the undoped diamond films average CPD of 650 mV and for boron doped layer 155 mV were achieved. Based on CPD values, the values of work functions were calculated as 4.65 eV and 5.15 eV for doped and undoped diamond film respectively. Boron-doping increases the carrier density and the conductivity of the material and, consequently, the Fermi level.
Fabrication and characterization of composite TiO2 nanotubes/ boron-doped diamond electrodes towards enhanced supercapacitors
- Michał Sobaszek
- Katatrzyna SiuzdaK
- Miroslaw Sawczak
- Jacek Ryl
- Robert Bogdanowicz
2016 Pełny tekst THIN SOLID FILMS
The composite TiO2 nanotubes / boron-doped diamond electrodes were deposited using Microwave Plasma Enhanced Chemical Vapor Deposition resulting in the improved electrochemical performance. This composite electrode can deliver high specific capacitance of 7.46 mF cm‐− 2 comparing to boron-doped diamond (BDD) deposited onto flat Ti plate (0.11 mF cm‐− 2).The morphology and composition of composite electrode were characterized by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. According to XPS and Raman analysisanalyses, the structure of TiO2 was greatly changed during Chemical Vapor Deposition process: formation of Ti3 + sites, partial anatase to rutile transformation and titanium carbide phase formation. This effect is attributed to the simultaneous presence of activated hydrogen and carbon in the plasma leading to enhanced dehydration of NTs (nanotubes) followed by carbon bonding. The enhanced capacitive effect of TiO2 NT / BDD could be recognized as: (1) the unique synergistic morphology of NTs and BDD providing more efficient conducting pathway for the diffusion of ions and (2) partial decomposition of NTs and transformation towards to TiC and Ti2O3 fractions. Finally, highly ordered titania nanotubes produced via simply, quick and controllable method – — anodization, could act as promising substrate for conductive BDD layer deposition and further application of such composites for supercapacitor construction.