2018 - Repozytorium publikacji - Politechnika Gdańska

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Temper bead welding of S460N steel in wet welding conditions
- Jacek Tomków
- Dariusz Fydrych
- Grzegorz Rogalski
- Jerzy Łabanowski
2018 Pełny tekst Advances in Materials Science
Wet welding is the most common method of welding in water environment. It is most often used for repairing of underwater parts of offshore structures. However, the water as a welding environment causes an increase of susceptibility of steels to cold cracking. For underwater constructions high strength low alloy (HSLA) steel are widely used. In wet welding condition a HSLA steel is characterized by high susceptibility to cold cracking. Temper Bead Welding (TBW) was chosen as a method to improve the weldability of S460N steel. The studies showed that TBW technique causes significant decrease of maximum hardness of heat affected zone (HAZ). The largest decrease in hardness occurred in specimens with the pitches in range 66-100%.
Temperature influence on tyre/road noise on poroelastic road surface based on laboratory measurements
- Piotr Mioduszewski
- Stanisław Taryma
- Ryszard Woźniak
2018 Pełny tekst
The temperature effect on measured tyre/road noise is very important phenomena as it may lead to significant errors in measurement results due to substantial influence of this parameter on the obtained values. It depends mainly on the particular tyre-road combination. It is different for dense and porous as well as for bituminous and cement concrete pavements. It differs also depending on tested tyre. The correction procedure for normalizing measured noise levels to a reference air temperature of 20 oC is given in the recently published ISO Technical Specification ISO/TS 13471-1:2017 – Correction for temperature when testing with the CPX method. The temperature correction coefficients defined in the Technical Specification differ to some extent depending on the main type and condition (porosity) of a road surface. They are equal for both standard reference tyres and they slightly depend linearly on speed. An extensive study dealing with temperature influence on tyre/road noise on poroelastic road surface was conducted in the laboratory of Gdansk University of Technology in Poland. The aim of this study was to define the temperature correction coefficients for this special - extremely quiet road surface and for various tyres (including two standard reference tyres). Noise measurements using the CPX method were performed at roadwheel facilities equipped with poroelastic road surface for twelve passenger car and for two truck tyres within the air temperature range from 6 to 36 ºC. The results and findings of this experiment are presented and discussed in this paper.
Temperature influences on shear stability of a nanosize plate with piezoelectricity effect
- Mohammad Malikan
2018 Pełny tekst Multidiscipline Modeling in Materials and Structures
Purpose The purpose of this paper is to predict the mechanical behavior of a piezoelectric nanoplate under shear stability by taking electric voltage into account in thermal environment. Design/methodology/approach Simplified first-order shear deformation theory has been used as a displacement field. Modified couple stress theory has been applied for considering small-size effects. An analytical solution has been taken into account for various boundary conditions. Findings The length scale impact on the results of any boundary conditions increases with an increase in l parameter. The effect of external electric voltage on the critical shear load is more than room temperature effects. With increasing aspect ratio the critical shear load decreases and external electric voltage becomes more impressive. By considering piezoelectric nanoplates, it is proved that the temperature rise cannot become a sensitive factor on the buckling behavior. The length scale parameter has more effect for more flexible boundary conditions than others. By considering nanosize, the consideration has led to much bigger critical load vs macro plate. Originality/value In the current paper for the first time the simplified first-order shear deformation theory is used for obtaining governing equations by using nonlinear strains for shear buckling of a piezoelectric nanoplate. The couple stress theory for the first time is applied on the nonlinear first-order shear deformation theory. For the first time, the thermal environment effects are considered on shear stability of a piezoelectric nanoplate.
Tensometria elektrooporowa, Wydawnictwo Ernst & Sohn w Berlinie
- Zbigniew Cywiński
2018 Mosty
Recenzja: Keil S.: Technology and Practival Use of Strain Gages. Ernst & Sohn, Berlin 2017
Tensor Decomposition for Imagined Speech Discrimination in EEG
- Jesus Garcia Salinas
- Luis Villaseñor-Pineda
- Carlos A. Reyes-Garćia
- Alejandro A. Torres-García
2018 LECTURE NOTES IN COMPUTER SCIENCE
Most of the researches in Electroencephalogram(EEG)-based Brain-Computer Interfaces (BCI) are focused on the use of motor imagery. As an attempt to improve the control of these interfaces, the use of language instead of movement has been recently explored, in the form of imagined speech. This work aims for the discrimination of imagined words in electroencephalogram signals. For this purpose, the analysis of multiple variables of the signal and their relation is considered by means of a multivariate data analysis, i.e., Parallel Factor Analysis (PARAFAC). In previous works, this method has demonstrated to be useful for EEG analysis. Nevertheless, to the best of our knowledge, this is the first attempt to analyze imagined speech signals using this approach. In addition, a novel use of the extracted PARAFAC components is proposed in order to improve the discrimination of the imagined words. The obtained results, besides of higher accuracy rates in comparison with related works, showed lower standard deviation among subjects suggesting the effectiveness and robustness of the proposed method. These results encourage the use of multivariate analysis for BCI applications in combination with imagined speech signals.
Termiczne metody utylizacji odpadów medycznych
- Roksana Bochniak
- Aleksandra Gołąbek
- Jan Wajs
2018 Technika Chłodnicza i Klimatyzacyjna
W artykule przedstawiono dopuszczone przez polskie prawo metody unieszkodliwiania odpadów medycznych, ze szczególnym wyróżnieniem najczęściej stosowanych metod termicznych. Omówiono wytyczne dla prowadzenia procesu utylizacji odpadów w instalacji termicznej przeróbki odpadów. W końcowej części publikacji opisane zostały dwie jednostki przeznaczone do utylizowania odpadów medycznych, tj. instalacja w Zakładzie Utylizacji Odpadów Medycznych przy Centrum Onkologii im. prof. F. Łukaszczyka w Bydgoszczy oraz Spalarnia Odpadów Przemysłowych i Medycznych Raf-Ekologia Sp. z o.o. w Jedliczu.
Ternary Bismuthide SrPtBi2: Computation and Experiment in Synergism to Explore Solid-State Materials
- Xin Gui
- Xin Zhao
- Zuzanna Sobczak
- Cai-Zhuang Wang
- Tomasz Klimczuk
- Kai-Ming Ho
- Weiwei Xie
2018 Journal of Physical Chemistry C
A combination of theoretical calculation and the experimental synthesis to explore the new ternary compound is demonstrated in the Sr–Pt–Bi system. Because Pt–Bi is considered as a new critical charge-transfer pair for superconductivity, it inspired us to investigate the Sr–Pt–Bi system. With a thorough calculation of all the known stable/metastable compounds in the Sr–Pt–Bi system and crystal structure predictions, the thermodynamic stability of hypothetical stoichiometry, SrPtBi2, is determined. Following the high-temperature synthesis and crystallographic analysis, the first ternary bismuthide in Sr–Pt–Bi, SrPtBi2 was prepared, and the stoichiometry was confirmed experimentally. SrPtBi2 crystallizes in the space group Pnma (S.G. 62, Pearson Symbol oP48), which matches well with theoretical prediction using an adaptive genetic algorithm. Using first-principles calculations, we demonstrate that the orthorhombic structure has lower formation energies than other 112 structure types, such as tetragonal BaMnBi2 (CuSmP2) and LaAuBi2 (CuHfSi2) structure types. The bonding analysis indicates that the Pt–Bi interactions play a critical role in structural stability. The physical property measurements show the metallic properties at the low temperature, which agrees with the electronic structure assessment.
Terpeny w powietrzu wewnętrznym cz. I. Ich rola i znaczenie w kształtowaniu jakości powietrza wewnętrznego
- Klaudia Pytel
- Renata Marcinkowska
- Bożena Zabiegała
2018 Analityka: Nauka i Praktyka
Potencjał terpenów do tworzenia cząstek wtórnego aerozolu organicznego (SOA) został po raz pierwszy opisany już w 1960 roku. Od tamtego czasu naukowcy poświęcili dużo uwagi tej tematyce. Dzięki temu wiedza na temat powstawania i wpływu SOA na organizmy żywe, a także rozumienie procesów odpowiedzialnych za jego powstawanie znacząco wzrosły.
TESTING CONTRACTION AND THERMAL EXPANSION COEFFICIENT OF CONSTRUCTION AND MOULDING POLYMER COMPOSITES
- Łukasz Pyrzowski
2018 Pełny tekst Polish Maritime Research
The paper presents results of systematic tests of contraction and thermal expansion coefficients of materials based on polymer composites. The information on the above material properties is essential both at the design stage and during the use of finished products. Components for the samples were selected in such a way as to represent typical materials used for production of construction and moulding elements. The performed tests made it possible to monitor the analysed parameters at different stages of the technological process.
Testing Question Order Effects of Self-perception of Risk Propensity on Simple Lottery Choices as Measures of the Actual Risk Propensity
- Jakub Golik
2018 Pełny tekst ASK: RESEARCH & METHODS
Uncertainty together with the necessity of making choices inevitably results in risky decisions. For many years now, scientists have been studying notions connected with risk such as risk management, risk perception or risk propensity. While many sophisticated methods regarding measurement of risk propensity have been developed so far, it seems that little attention has been paid to checking whether they are not inherently flawed. The main goal of this article is to check with a simple preliminary study whether questionnaire based methods of risk propensity assessment are not susceptible to question order effects. The research is focused on respondents’ answers to simple lottery choices as measures of their risk propensity. However, what would happen if the respondents were first asked how they perceive their own risk propensity? In order to answer this query a few questions designed to measure risk propensity and self-perception of risk propensity have been interspersed in a questionnaire of another research project. Furthermore, as an additional output of the study, the correlation has been checked between self-perception of risk propensity and the actual assessment of risk propensity based on the questions used. The results of the study show that question order effects are partially present in the setting described. Some conclusions and recommendations for further research are made based on the results. Finally, it can be concluded from the research that simple self-perception of risk propensity was significantly correlated with measures of actual risk propensity used.
Testing Students’ Entrepreneurial Self-Efficacy as an Early Predictor of Entrepreneurial Activities. Evidence From the SEAS Project
- Krzysztof Zięba
- Jakub Golik
2018 Pełny tekst Journal of Entrepreneurship, Management and Innovation
Over the last forty years, since Bandura (1977) introduced the concept of self-efficacy, there have been a constantly growing number of research publications using this concept. Its early development resulted in the creation of a new construct of entrepreneurial self-efficacy (ESE) proposed for the first time by (Chen et al. 1998). Since then, many different groups of research concerning ESE have emerged - one of them is the study of ESE of students. With regard to this particular group, a recent tendency to study ESE in a pre-post setting can be noticed i.a. Karlsson, Moberg (2013), Shinnar, Hsu, Powell (2014), Ismail, Zain, Zulihar (2015). Due to the increasing interest in entrepreneurial self-efficacy research and the need to fill the gap in the literature with regard to European post-communist countries (and particularly – Poland) (Drnovsek, Wincent, Cardon, 2010), in this paper we present a brief overview of ESE research and pose the question whether ESE of Polish students can serve as an early predictor of their subsequent entrepreneurial activities, potentially leading them to nascent entrepreneurship. The research material was collected from the SEAS (Survey on Entrepreneurial Attitudes of Students) Project carried out at the Faculty of Management and Economics, Gdańsk University of Technology. The research sample was composed of 72 students - ESE was measured in a pre-post setting using a single item based on a five-point Likert scale. One of the research conclusions is that ESE manifested by student-beginners seems to influence their later entrepreneurial behavior in a statistically significant way - potentially making ESE a valuable early predictor of future entrepreneurial activities. In the concluding part of the study, limitations are discussed and future study developments are indicated.
Text Categorization Improvement via User Interaction
- Jakub Atroszko
- Julian Szymański
- David Gil
- Higinio Mora
2018
In this paper, we propose an approach to improvement of text categorization using interaction with the user. The quality of categorization has been defined in terms of a distribution of objects related to the classes and projected on the self-organizing maps. For the experiments, we use the articles and categories from the subset of Simple Wikipedia. We test three different approaches for text representation. As a baseline we use Bag-of-Words with weighting based on Term Frequency-Inverse Document Frequency that has been used for evaluation of neural representations of words and documents: Word2Vec and Paragraph Vector. In the representation, we identify subsets of features that are the most useful for differentiating classes. They have been presented to the user, and his or her selection allow increase the coherence of the articles that belong to the same category and thus are close on the SOM.
Text Mining Algorithms for Extracting Brand Knowledge; The fashion Industry Case
- Nina Rizun
- Wioleta Kucharska
2018 Pełny tekst
Brand knowledge is determined by customer knowledge. The opportunity to develop brands based on customer knowledge management has never been greater. Social media as a set of leading communication platforms enable peer to peer interplays between customers and brands. A large stream of such interactions is a great source of information which, when thoroughly analyzed, can become a source of innovation and lead to competitive advantage. Semantic analysis is a prominent field of data mining that deals with key contexts, topics, and sentiment of these interactions. The challenge and key to the success are creating a proper searching algorithm to analyze these areas of interest. The purpose of this study is to develop and to test a methodology which will identify principal points of customers' interactions with fashion brands using a set of Text Mining Algorithms. The fashion industry is one of the most successful in the social media environment. Deep understanding of fashion brand communication is interesting from the theoretical and practical point of view. The theoretical value of this study contributes to the social media brand knowledge management by providing a set of gained insights thanks to the implementation of the new methodological approach presented in this study. The practical value is the knowledge about the presence of fashion brands in social media obtained in the course of the study.
THE AGRI-HOOD AND SLOW-SUBURB CONCEPT IN THE CONTEXT OF AN IN-BETWEEN CITY (ZWISCHENSTADT)
- Gabriela Maria Rembarz
2018
The concept of an “in-between-city” (Zwischenstadt) interprets the urban sprawl in Europe as a new, evolving model of urban development, taking the form of urbanized landscapes, which does not correspond with the traditional understanding of urban design. The actual shape of an in-between-city reflects the today’s technology and economy generating new lifestyles: global trends coexist with the locality in a strong relation. The qualification process concordant with the new logic of space creation requires new planning tools. The notion of a slow-suburb, developed on the basis of the agri-hood concept, could be recognized as a new planning category, related to agrarian urbanism. The purpose of introducing the concept of slow city into the planning for metropolitan regions entails addressing the appearing needs firstly, in order to differentiate the metropolitan life style offer, and secondly, to focus on the values represented in the historical suburban relicts, which could be used in the new suburbanization policy. The slow-suburb concept, referring to the research on in-between city, unknown in Poland, addresses the local potentials and the needs.
The algorithm of building the hierarchical contextual framework of textual corpora
- Nina Rizun
- Wojciech Waloszek
2018 Pełny tekst
This paper presents an approach for Modeling the Latent Semantic Relations. The approach is based on advantages of two computational approaches: Latent Semantic Analysis and Latent Dirichlet Allocation. The scientific question about the possibility of reducing the influence of these Methods limitation on the Quality of the Latent Semantic Relations Analysis Results is raised. The case study for building the Two-level Hierarchical Contextual Framework of Textual Corpora was performed. The main scientific contributions of this research are: using the paragraphs as a topically completed textual messages can guarantee that it will be centered on a single topic; collecting the topics within the Corpora via its identification in each document separately is the instrument for preventing the model size increasing; film’s review as a specific type of textual document have the approximately similar writing style only within the Corpora with the same semantic tonality.
The analysis of firms’ involvement in internationalisation and determinants of its intensity – an analysis for developing and post-transition economies
- Joanna Wolszczak-Derlacz
2018 Pełny tekst Economics and Business Review
The study presents the empirical analysis of firms’ involvement in different forms of internationalisation: export, indirect export, import, indirect import and finally simultaneous exporting and importing. The analysis is based on firm-level data from the World Bank Enterprise Survey (March 2017 release). The empirical part is divided into two stages. Firstly account is taken of firms’ heterogeneity and then a Melitz type analysis of the firms’ likeliness of being involved in international activity is performed. Secondly the sample of firms is limited to only those involved in the internationalisation process and then a regression is carried out with the export/import intensity being the dependent variable. The results indicate that determinants of the foreign markets are different from those connected with trade intensity with the exception of the foreign ownership which is the only one associated in the same way with involvement in internationalisation and with its intensity.
The analysis of temperature changes of the saliva traces left on the fur during laboratory rats social contacts
- Magdalena Mazur-Milecka
- Jacek Rumiński
2018
Automatic analysis of complex rodent social be- havior, especially aggressive ones, is of important scientific interest. In this paper we analyze the properties of the data created as a result of aggressive rodent social behavior. Detec- tion of specific aggressive behaviors is based on the event of leaving traces of saliva on the fur of the attacked individual, which are clearly visible in the thermal imaging. The traces change temperature in time in a specific way. After bite, saliva is cooled and then heated to the body temperature. Usage of this method in social behavior analysis ensures detection and tracking aggressive behaviors even if the event itself is invisible.
The analysis of the accuracy of spatial models using photogrammetric software: Agisoft Photoscan and Pix4D
- Tadeusz Widerski
- Karol Daliga
- Adrianna Barbasiewicz
2018
This article was created as a result of research conducted within the master thesis. The purpose of the measurements was to analyze the accuracy of the positioning of points by computer programs. Selected software was a specialized computer software dedicated to photogrammetric work. For comparative purposes it was decided to use tools with similar functionality. As the basic parameters that affect the results selected the resolution of the photos on which the key points were searched. In order to determine the location of the determined points, it was decided to follow the photogrammetric resection rule. In order to automate the measurement, the measurement session planning was omitted. The coordinates of the points collected by the tachymetric measure were used as a reference system. The resulting deviations and linear displacements oscillate in millimeters. The visual aspects of the cloud points have also been briefly analyzed.
The analysis of the determination of points positions using photogrammetric methods
- Tadeusz Widerski
- Karol Daliga
- Adrianna Barbasiewicz
2018
This article was created as a result of research conducted within the master thesis. The purpose of the research was to analyze the accuracy of determining the actual position of the photographed points according to the calculated parameters. The accuracy of photos alignment was determined as parameters, which determine their external and internal orientation. In order to determine the location of the determined points, it was decided to follow the photogrammetric resection rule. In order to automate the measurement, the measurement session planning was omitted. The resulting deviations and linear displacements oscillate in millimeters. Analysis was performed for 3 levels of alignment accuracy. For each align level, line differences of photopoints coordinates obtained from photogrammetric model and total station measurements were analysed. There were also analysed horizontal and vertical directions of photopoints location. In this way were obtained parameters similar to “displacement” vector connecting points measured by total station and estimated from photogrammetric model.
The analysis of the influence of the corrosion protection method of selected steel elements on the steel structure life cycle costs
- Adam Kristowski
- Beata Grzyl
- Dariusz Kowalski
2018 Pełny tekst
Steel products are widely used in the construction for the performance of essential and additional elements of engineering structures. They are characterized by high tensile strength, compression and bending, the structure homogeneity, the possibility of assembly regardless of the season and climatic conditions, ease of processing and the possibility of almost any shape. The main disadvantage of steel structures is their high susceptibility to corrosion, which depends on local operating conditions and the type of applied corrosion protection system. The aim of the research carried out by the authors is to indicate the possibility of reducing the costs associated with anti-corrosion protection, incurred at the stage of operation of the steel structure over a period of several decades. The scope of the research includes the life cycle cost analysis for selected steel elements using three alternative corrosion protection systems. The subject of the research is the analysis of the influence of the corrosion protection method of selected steel constructions on its life cycle costs. On the chosen example of the selected object and problems related to its use and maintenance, the possibility of using a singlelayer protection in the form of a metallization coating made in a hot-dip galvanizing process, a three-layer varnish coating based on liquid paints and protection composed of a galvanized metallization coating and a two-layer paint coating is considered. The assessment is carried out in accordance with the life-cycle cost estimation algorithm (LCC).