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Publications from the year 2016
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2015. Motion analysis of a kitesurfer employing a vision-based measurement system
- Anna Grzeczka
- Maciej Kłaczyński
- Edmund Wittbrodt
- Tadeusz Uhl
- Piotr Kohut
Abstract. Kitesurfing is a relatively new phenomenon with rising popularity worldwide – a recently developed extreme watersport considered a high-risk injury sport. It combines elements of several other sports, in particular, sailing, surfing, windsurfing, wakeboarding, and snowboarding. The main purpose of authors’ research in the present paper is to use a vision-based system for measuring a kitesurfer’s body movements in order to analyze the group of activated muscles during take-off and basic freestyle trick. The authors put a special emphasis on the handle pass trick, as it is very effective and, at the same time, one of the most destructive tricks for the kitesurfer’s shoulder joint. Another issue examined in this paper was how to perform kitesurfing tricks in laboratory conditions in order to measure kinematics in natural environmental.
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3 Hz – WYMÓG KONIECZNY?
- Mikołaj Miśkiewicz
- Łukasz Pyrzowski
- Jacek Chróścielewski
- Krzysztof Wilde
Referat jest pewnym przyczynkiem do dyskusji nad formalnymi uwarunkowaniami ujętymi w różnych dokumentach, a dotyczących wymagań z zakresu dynamiki mostów. W szczególności zapisu cyt.: ,,Stany graniczne użytkowania uważa się za przekroczone, jeżeli wymagania użytkowe dotyczące konstrukcji obiektu nie są dotrzymane. Oznacza to, że w konstrukcji obiektu nie powinny wystąpić: … 4) drgania własne o częstotliwości mniejszej niż 3 Hz”; wg. §147.3, ust. 4 Rozporządzenia Ministra Transportu i Gospodarki Morskiej z dnia 30 maja 2000 r. W referacie przedstawiono pewne rozważania teoretyczne, przegląd tzw. stanu prawnego regulującego wymagania w zakresie odpowiedzi dynamicznej obiektów mostowych oraz wzmianek, które na ten temat pojawiają się w literaturze przedmiotu. Ponadto, na podstawie doświadczeń własnych i dociekań innych autorów, zebrano charakterystyki dynamiczne konstrukcji mostowych, które pomimo niespełniania narzuconego przepisami wzmiankowanego warunku są bezpiecznie użytkowane od wielu lat.
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3D Acoustic Field Intensity Probe Design and Measurements
- Józef Kotus
- Andrzej Czyżewski
- Bożena Kostek
The aim of this paper is two-fold. First, some basic notions on acoustic field intensity and its measurement are shortly recalled. Then, the equipment and the measurement procedure used in the sound intensity in the performed research study are described. The second goal is to present details of the design of the engineered 3D intensity probe, as well as the algorithms developed and applied for that purpose. Results of the intensity probe measurements along with the calibration procedure are then contained and discussed. Comparison between the engineered and the reference commercial probe confirms that the designed construction is applicable to the sound field intensity measurements with a sufficient effectiveness.
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3D Monitoring - Identification of measurement problems at larger movements of the tracked points
- Karol Daliga
- Daria Filipiak-Kowszyk
- Karolina Makowska
- Jakub Szulwic
Authors identified the problems associated with the determination of the controlled points coordinates by use of automated Total Station placed behind transparent barrier. Important thing in the mentioned analysis was a large change of controlled points position and not stable Total Station’s stand (because of stand’s thermal drift). This two elements, combined with measurement made through glass plate determine the need for impact analysis of measurement conditions for measurement results. The analysis was performed for roof made of technical fabric. Because of changing weather conditions, the displacement of some points reached 1.3 m. It caused some technical problems with tracking measurement points. Furthermore, it had an impact for range of laser’s beam incidence angle change which causes a “changeable” systematic measurement error. In this paper the authors presents the analysis connected with the determination of the impact of leser beam deflection passing through glass plate on the final results.
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3D polypyrrole structures as a sensing material for glucose detection
- Karolina Cysewska
- Magdalena Szymańska
- Piotr Jasiński
In this work, 3D polypyrrole (PPy) structures as material for glucose detection is proposed. Polypyrrole was electrochemically polymerized on platinum screen-printed electrode from an aqueous solution of lithium perchlorate and pyrrole. The growth mechanism of such PPy structures was studied by ex-situ scanning electron microscopy. Preliminary studies show that studied here PPy film is a good candidate as a sensing material for glucose biosensor. It exhibits very high sensitivity (28.5 mA·mM-1·cm-2) and can work without any additional dopants, mediators or enzymes. It was also shown that glucose detection depends on the PPy morphology. The same PPy material was immobilized with the glucose oxidase enzyme. Such material exhibited higher signal response, however it lost its stability very fast.
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3-MCPD: A worldwide problem of food chemistry
- Renata Marcinkowska
- Magdalena Kupska
- Agnieszka Głowacz-Różyńska
- Justyna Gromadzka
- Jacek Namieśnik
3-MCPD is a heat-induced food contaminant which has been widely investigated for decades. This paper presents an overview of current knowledge about 3-MCPD including its formation routes, occurrence in various foodstuffs, analytical approach, toxicological aspects and future research perspectives. So far 3-MCPD was determined in its free and bound form in thermally-treated foods, edible oils and fats, and infant foods including human breast milk. Infant foods and human breast milk were highlighted in this paper as a serious problem due to the fact that they can pose a potential hazard for infants. The analytical approach of 3-MCPD determination have been modified for over a decade. Nowadays the method based on determining the derivative of this compound by using GC-MS is widely used. However there is still a big need for developing new methods which would produce repeatable results. Some of the toxicological aspects associated with 3-MCPD still remain unknown. A number of studies on carcinogenicity and genotoxicity of 3-MCPD were carried out on rodents however no clinical studies on humans have been reported so far. Also, both detrimental effect on kidneys and antifertility activity have been widely reported. Moreover, the knowledge about 3-MCPD absorption into body fluids and tissues, and its metabolic pathways is based on sometimes conflicting data derived from different studies. In conclusion, although a lot of research was carried out on the topic of 3-MCPD, there is still a need for further research in this area.
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50 lat minęło - z historii studenckich seminariów naukowych mechaników
- Adam Barylski
Przedstawiono 50-letnią historie Seminariów Naukowych Studentów i Młodych Inżynierów Mechaników na Wydziale Mechanicznym PG. Podano organizatorów poszczególnych edycji oraz zwycięzców wygłoszonych referatów w kategorii studenci, dyplomanci i doktoranci. W seminariach brali udział nie tylko uczestnicy z Politechniki Gdańskiej, ale i z innych technicznych uczelni krajowych i zagranicznych.
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5-Bromo-2′-deoxycytidine—a potential DNA photosensitizer
- Magdalena Zdrowowicz
- Paweł Wityk
- Barbara Michalska
- Janusz Rak
A double-stranded oligonucleotide, 80 base pairs in length, was multiply labeled with 5-bromo-2′-deoxycytidine (BrdC) using polymerase chain reaction (PCR). The modified oligonucleotide was irradiated with 300 nm photons and its damage was assayed by employing DHPLC, LC-MS and denaturing polyacrylamide gel electrophoresis (PAGE). Two types of damage were demonstrated, namely, single strand breaks (SSBs) and intrastrand cross-links (ICLs); the ICLs were in the form of d(G^C) and d(C^C) dimers. The former species are probably formed due to photoinduced electron transfer between the photoexcited BrdC and the ground state 2′-deoxyguanosine (dG), whereas the latter is a result of a cycloaddition reaction. Since SSBs and ICLs are potentially lethal to the cell, BrdC could be considered as a nucleoside with possible clinical applications.
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A BRIEF REVIEW AND COMPARISON OF SELECTED EXPERIMENTAL METHODS FOR MEASURING NATURAL FREQUENCIES OF CIRCULAR SAW BLADES
- Anna Danuta Kaczmarek-Peniakova
- Kazimierz Orłowski
- Lubomir Javorek
Different methods for the empirical determination of the natural frequencies of circular saw blades are presented. Stationary methods, such as the harmonic and impulse tests, are discussed and the results of related comparison are given. The comparison of the methods revealed their degree of practical usefulness and their accuracy in determining natural frequencies. A combination of specific methods is proposed, which should allow optimal results.
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A Colorimetric Microplate Assay for DNA-Binding Activity of His-Tagged MutS Protein
- Michał Banasik
- Paweł Sachadyn
A simple microplate method was designed for rapid testing DNA-binding activity of proteins. The principle of the assay involves binding of tested DNA by his-tagged protein immobilized on a nickel-coated ELISA plate, following colorimetric detection of biotinylated DNA with avidin conjugated to horseradish peroxidase. The method was used to compare DNA mismatch binding activities of MutS proteins from three bacterial species. The assay required relatively low amounts of tested protein (approximately 0.5–10 pmol) and DNA (0.1–10 pmol) and a relatively short time of analysis (up to 60 min). The method is very simple to apply and convenient to test different buffer conditions of DNA–protein binding. Sensitive colorimetric detection enables naked eye observations and quantitation with an ELISA reader. The performance of the assay, which we believe is a distinguishing trait of the method, is based on two strong and specific molecular interactions: binding of a his-tagged protein to a nickel-coated microplate and binding of biotinylated DNA to avidin. In the reported experiments, the solution was used to optimize the conditions for DNA mismatch binding by MutS protein; however, the approach could be implemented to test nucleic acids interactions with any protein of interest.
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A commercial of the shelf components for a unmanned air vehicle photogrammetry
- Paweł Burdziakowski
- Jakub Szulwic
A photogrammetry from a unmanned aerial vehicle (UAV) can be understood as a new measurement tool. Is introduces a low-cost alternatives for a traditional aerial photogrammetry. A commercial off-the-shelf products (COTS), that are commercially available for a costumers, are the standard manufactures products, not custom. COTS products are available in the commercial market and can be bought and used under government contract. That fact makes it cheaper and available for all. Motivations for using COTS components is a reduction of overall system-development and costs and long-term maintenance costs. An aviation offers a different types of aircraft. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion. All those types offers different attributes, that are more or less desirable for UAV photogrammetry. A methodology for determining a platform type was developed in this research, and the most suitable platform for a photogrammetry measurements was chosen. In order to build a UAV platform for photogrammetry tasks, products available on commercial market were analyzed with characteristics and technical data.
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A concept of measurement system based on the Z-Wave standard
- Michał Kowalewski
In the paper a new concept of measurement system based on the Z-Wave standard is presented. This standard is dedicated to use mainly in home automation systems, but its properties enable to use it in dispersed measurement systems and support wireless communication between measurement nodes in a mesh-type network. In the paper basic metrological aspects of the Z-Wave standard and an example of impedance measurement system are discussed.
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A concept of Signal Equalization Method Based on Music Genre and the Listener's Room Characteristics
- Bożena Kostek
- Piotr Hoffmann
A research study that investigates the influence of the room acoustics environment on the frequency characteristic of the audio signal playback is presented. First, a novel spectral equalization method of the room acoustic conditions is introduced. On the basis of the frequency response of the room, a system for room acoustics compensation based on eight-band equalizer is proposed. The system settings depend on music genre. In order to acquire room acoustic characteristics, a series of measurements are performed. Reverberation times and frequency responses of four rooms are acquired. White noise serving as reference signal and audio excerpts belonging to six music genres are utilized in measurements. For audio normalization LUFS (Loudness Unit, referenced to Full Scale) scale is employed, therefore all audio tracks are adjusted to -23 LUFS signal level. Recorded signals in the listener’s receiver position are then used to obtain room equalization characteristics. A comparison between the results obtained with the method introduced and a traditional graphic equalizer, based on preliminary subjective tests, is given. It is shown that room equalization based on the method proposed is effective in room acoustic deficiencies improvement.
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A Conception of Pairwise Comparisons Model for Selection of Appropriate Body Surface Area Calculation Formula
- Grzegorz Redlarski
- Waldemar W. Koczkodaj
- Marek Krawczuk
- Janusz Siebert
- Katarzyna Elżbieta Mrozik
- Aleksander Pałkowski
- Piotr Tojza
Body surface area (BSA) may be computed using a variety of formulas, but the computed BSA differs from real BSA values for particular subjects. This is presented in the paper by computing BSA values for selected subject and comparing them to the real BSA value obtained with the use of a 3D body scanner. The results show inequalities in the relevant BSA computing formulas. Hence, there is a need to determine a method that will allow to select the best formula for calculating BSA in a particular case. For this purpose, the pairwise comparisons (PC) method is suggested. This article presents a proposition of using consistency-driven PC, as well as the basic and most important aspects of using PC to determine the appropriate BSA calculation formula.
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A CONTEXT IN RECOMMENDER SYSTEMS
- Aleksandra Karpus
Recommender systems aim to propose potentially interesting items to a user based on his preferences or previous interaction with the system. In the last decade, researcher found out that known recommendation techniques are not sufficient to predict user decisions. It has been noticed that user preferences strongly depend on the context in which he currently is. This raises new challenges for the researchers such as how to obtain contextual information, how to model context and use it to make predictions. In this paper we discuss the main idea of context-aware recommender systems and describe paradigms for incorporating context in recommendation process with some examples. We show how important and hard task is the choice of contextual parameters, present which of them are useful in different domains and describe a method for choosing relevant context variables. We also discuss different context-aware recommender systems that utilize ontologies in different ways in the recommendation process.
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A convenient method for the preparation of functionalized N-acylsulfenamides from primary amides.
- Mateusz Musiejuk
- Dariusz Witt
We have developed a convenient method for the synthesis of functionalized N-acylsulfenamides under mild conditions and in moderate to good yields. The designed method is based on the reaction of (5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)-disulfanyl derivatives with nitrogen nucleophiles generated from primary amides or imides and sodium hydride. The developed method allows for the preparation of N-acylsulfenamides bearing additional hydroxyl, carboxyl, or amino functionalities.
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A coupled constitutive model for fracture in plain concrete based on continuum theory with non-local softening and eXtended Finite Element Method
- Jerzy Bobiński
- Andrzej Tejchman-Konarzewski
The paper presents a constitutive model for concrete which combines a continuous and discontinuous fracture description. In a continuum regime, two different constitutive laws were used. First, a plasticity model with a Rankine failure criterion and an associated fl ow rule was used. Second, a constitutive law based on isotropic damage mechanics was formulated. In order to capture the width of a localized zone and to obtain mesh-independent results, both models were equipped with a characteristic length of micro-structure by applying a non-local theory of an integral format. In order to describe a macro-crack as a displacement jump along/across a localized zone, the eXtended Finite Element Method (XFEM) was used. A transition algorithm between a non-local continuum model and XFEM was formulated. The implementation details of a coupled approach were given. The performance of two coupled models were numerically analysed based on several 2D benchmarks with a dominating mode-I (e.g. uniaxial tension and bending) and under mixed-mode conditions. The numerical results were compared with our experimental ones. The advantages of a continuous – discontinuous coupling in describing crack patterns were outlined.
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A decision-making system supporting selection of commanded outputs for a ship's propulsion system with a controllable pitch propeller
- Krzysztof Rudzki
- Wiesław Tarełko
The ship's operators have to make decisions regarding the values of commanded outputs (commanded engine speed and pitch ratio) which ensure maximum vessel speed and minimum fuel consumption. Obviously, the presented decision problems are opposed. Therefore, there is a need for a compromise solution that enables more flexible vessel voyage planning. This paper deals with development of a computer-aided system supporting selection of commanded outputs (commanded engine speed and pitch ratio) for a ship's propulsion system with a controllable pitch propeller. The main component of this system is the decision-making system. In particular, development of both the functional models using ANN techniques, and the two-objective optimization model of the mentioned decision-making system are presented.
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A Fail-Safe NVRAM Based Mechanism for Efficient Creation and Recovery of Data Copies in Parallel MPI Applications
- Artur Malinowski
- Paweł Czarnul
- Maciej Maciejewski
- Paweł Skowron
The paper presents a fail-safe NVRAM based mechanism for creation and recovery of data copies during parallel MPI application runtime. Specifically, we target a cluster environment in which each node has an NVRAM installed in it. Our previously developed extension to the MPI I/O API can take advantage of NVRAM regions in order to provide an NVRAM based cache like mechanism to significantly speed up I/O operations and allow to preload large files and operate efficiently on them. In this work, we show how to provide fail safe data write to such files using NVRAM and how to recover from failures. This provides an efficient alternative to costly checkpointing provided an application can store its consistent state in a file.