2018 - Repozytorium publikacji - Politechnika Gdańska

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Evaluation of the structures size in the liquid-gas flow by gamma-ray absorption
- Marcin Zych
- Robert Hanus
- Marek Jaszczur
- Dariusz Świsulski
- Leszek Petryka
- Paweł Jodłowski
- Piotr Zych
2018 Pełny tekst EPJ Web of Conferences
The rapid development of tomography methods particularly electrical, X and gamma rays allows for a wide range of the information about flow structure. However, all of such methods are quite complicated. At the same time much simpler systems as the measuring system of gamma rays absorption, allows to obtain a all key flow information which describe the two-phase flow. In the article the results of analyzes of radiometric signal that not only allow to recognize the type of flow, but also the assessment of forming structures are presented. Calculation and interpretation of the data were based on the crosscorrelation and cross-spectral density function. In order to verify the calculations the photographic documentation made during the measurements was used.
Evaluation of Three Peptide Immobilization Techniques on a QCM Surface Related to Acetaldehyde Responses in the Gas Phase
- Tomasz Wasilewski
- Bartosz Szulczyński
- Wojciech Kamysz
- Jacek Gębicki
- Jacek Namieśnik
2018 Pełny tekst SENSORS
The quartz-crystal microbalance is a sensitive and universal tool for measuring concentrations of various gases in the air. Biochemical functionalization of the QCM electrode allows a label-free detection of specific molecular interactions with high sensitivity and specificity. In addition, it enables a real-time determination of its kinetic rates and affinity constants. This makes QCM a versatile bioanalytical screening tool for various applications, with surface modifications ranging from the detection of single molecular monolayers to whole cells. Various types of biomaterials, including peptides mapping the binding sites of olfactory receptors, can be deposited as a sensitive element on the surface of the electrodes. One of key ways to ensure the sensitivity and accuracy of the sensor is provided by application of an optimal and repeatable method of immobilization. Therefore, effective sensors operation requires development of an optimal method of deposition. This paper reviews popular techniques (drop-casting, spin-coating, dip-coating) for coating peptides on piezoelectric crystals surface.
Evaluation the P-Delta Effect on Collapse Capacity of Adjacent Structures Subjected to Far-field Ground Motions
- Farzin Kazemi
- Benyamin Mohebi
- Mansoor Yakhchalian
2018 Pełny tekst Civil Engineering Journal-Tehran
In urban areas, adjacent structures can be seen in any insufficient distance from each other, because of economic reasons ‎and refusal of acquired minimum separation distance according to seismic previsions. Collapse capacity assessment of ‎structures is one of the important objectives of performance-based seismic engineering. The purpose of this study is to ‎consider the pounding phenomenon and P-Delta effect in seismic collapse capacity assessment of structures. For this ‎purpose, 2-, 4-, 6- and 8-story adjacent structures with different conditions of separation distance among them, were ‎modeled in the OpenSees software. Furthermore, Incremental Dynamic Analyses (IDAs) were performed using 78 far-field ‎ground motion records to compute the collapse capacities of adjacent structures. The results obtained from IDAs for ‎adjacent structures show that during pounding, taller structure reaches its collapse capacity earlier than shorter one. In ‎addition, by considering the P-Delta effect and increasing the distance between adjacent structures, time of collapse and ‎number of impacts increases. According to results, considering the P-Delta effect in modeling has significant influence in ‎seismic collapse capacity assessment of pounding structures.‎
Evidence-Based Risk Management for Civil Engineering Projects Using Bayesian Belief Networks (BBN)
- Agata Siemaszko
- Beata Grzyl
- Adam Kristowski
2018
The authors are seeking new methods for improving the efficiency of the investments associated with the maintenance and operation of existing civil engineering structures. It is demonstrated how the knowledge about the elements of construction and operation phases and their relationships, combined with monitoring data can be used for more effective management of the risks associated with civil engineering projects. The methodology chosen for estimating the probabilities of risk events is known as Bayesian Belief Networks (BBNs). To better illustrate how the proposed approach works the authors use the example of multi-family residential building located in Gdansk made in the wood-frame technology.
eVisa’s impacts on travel and tourism: the case of Turkey.
- Kadir Çakar
- Nadzeya Kalbaska
- Ali I Inanir
- Tuba Oren Sahin
2018 Journal of Hospitality and Tourism Technology
he purpose of this study was to investigate eVisa applications. eVisa is a service that falls under eTourism, whose growing use can be attributed to its ability to simplify the process of obtaining a visa. The objectives of this study were twofold: to explore the eVisa experience of tourists who have previously visited Turkey by using the service and to analyse the perceptions of stakeholders who have contributed to eVisa.
EvOLAP Graph – Evolution and OLAP-Aware Graph Data Model
- Gumińska Ewa
- Teresa Zawadzka
2018 Pełny tekst
The objective of this paper is to propose a graph model that would be suitable for providing OLAP features on graph databases. The included features allow for a multidimensional and multilevel view on data and support analytical queries on operational and historical graph data. In contrast to many existing approaches tailored for static graphs, the paper addresses the issue for the changing graph schema. The model, named Evolution and OLAP-aware Graph (EvOLAP Graph), has been implemented on a time-based, versioned property graph model implemented in Neo4j graph database.
Examination of the factors influencing binaural rendering on headphones with the use of directivity patterns
- Bartłomiej Mróz
2018
This paper presents a study on the influence of the directional sound sources with the use of the directivity patterns. This contribution also includes a comparison to the work done by Wendt et al., where several directivity pattern designs used to gradually control the auditory source distance in a room were showed. While the tests of Wendt et al. were done by auralizing source and room using a loudspeaker ring in an anechoic chamber, this study aims at investigating whether the effect performs similarly in binaural auralization over headphone playback. The study includes not only the auditory source distance, but also tries to discover the influence of auralised room characteristics, source-to-receiver distance, and signal on auditory externalisation.
Examining Feature Vector for Phoneme Recognition
- Grazina Korvel
- Bożena Kostek
2018
The aim of this paper is to analyze usability of descriptors coming from music information retrieval to the phoneme analysis. The case study presented consists in several steps. First, a short overview of parameters utilized in speech analysis is given. Then, a set of time and frequency domain-based parameters is selected and discussed in the context of stop consonant acoustical characteristics. A toolbox created for this purpose in the Matlab environment is presented. The next analysis step includes the process of selecting the most discriminating descriptors based on Bron Kerbosch algorithm. It is shown that parameters resulted from this analysis can be used for separation of consonants. Finally, phoneme recognition is performed employing k-NN classifier. Keywords: Phoneme analysis, parametrization, phoneme recognition, k-NN classifier
Examining Government-Citizen Interactions on Twitter using Visual and Sentiment Analysis
- Rocio Hubert
- Elsa Estevez
- Ana Maguitman
- Tomasz Janowski
2018 Pełny tekst
The goal of this paper is to propose a methodology comprising a range of visualization techniques to analyze the interactions between government and citizens on the issues of public concern taking place on Twitter, mainly through the official government or ministry accounts. The methodology addresses: 1) the level of government activity in different countries and sectors; 2) the topics that are addressed through such activities; 3) the resources shared between government and citizens as part of interactions; 4) the intensity of citizen response to government announcements; 5) the sentiment expressed by citizens when providing such responses; and 6) the combinations of such issues. Example combinations include identifying topics that generated the largest Twitter activity by government but received the least interest from citizens, identifying topics that generated the most polarized reactions from citizens, or determining correlation between policy announcements and trust, fear and other negative emotions expressed by citizens. The methodology uses visual analytics to reveal patterns and trends associated with various questions, complemented with sentiment analysis to study government-citizen interactions on Twitter. The methodology is validated by examining Twitter presence in five sectors – health, social development, education, environment and work, in five Latin American countries with mature e-Participation capabilities – Argentina, Chile, Colombia, Mexico and Uruguay.
Examples of Taxation on Real Estate Properties as an Long-term Investment Asset. Description of Situation in Selected European Countries
- Piotr Kasprzak
2018 Pełny tekst Przedsiębiorczość i Zarządzanie
Real estate properties have become the alternative asset for long-term savings and investments. Such investment however is strictly related to risk inter alia taxation policy. The following article describes and discusses both theoretical and practical aspects of long-term investment taxation imposed on real estate market in selected European countries. The article presents the analyses of the taxes including its functions, mechanisms and in particular income, real estate and indirect taxes on investments such real estate properties. The author analysed the literature both historical and modern to research the topic. The idea of investment taxation has been present in modern tax system for several decades including its positive and negative consequences. The research method includes data, literature and professional reports analyses. The analyses leads to the conclusion of the level, aim and the overall base of properties’ taxation in selected European countries.
Exchange-traded products in Germany: development and substitution of exchange-traded funds, exchange-traded commodities and exchange-traded notes.
- Adam Marszk
2018 Pełny tekst EQUILIBRIUM Quarterly Journal of Economics and Economic Policy
Research background: Exchange-traded products (ETPs) are one of the most rapidly growing categories of financial products. Their fast development has been boosted by innovative features. Three main categories of ETPs are exchange-traded funds (ETFs), exchange-traded commodities (ETCs) and exchange-traded notes (ETNs). ETCs and ETNs remain least known, even though their number on some stock exchanges is high. In Europe, Germany is one of the largest and most active ETPs markets. ETCs and ETNs are debt instruments, in contrast with the most popular ETFs, which are equity securities. Therefore, they offer investors different advantages but also expose them to other types of risks. Purpose of the article: The key aim of the article is to present the features of ETPs and to provide in-depth insight into the issues linked with the development of ETPs market in Germany, with the special emphasis on the ETCs and ETNs. Methodology/methods: In the main empirical part of the article, German ETPs market is analyzed using descriptive statistics and technological substitution framework (employed for the analysis of innovations in order to evaluate the changing market shares of, first, ETFs versus ETCs and ETNs, as well as, second, ETFs versus other types of investment funds). The period of the analysis is 2010-2016 in the former case and 2007-2016 in the latter. Findings: Share of ETPs other than ETFs in the total market in Germany remains low. Even though market position of the leading products, i.e. ETFs, is still very strong, some substitution has been observed, especially after 2015. Predictions indicate that this trend will continue in the upcoming years. Results of the analysis of the investment funds’ market confirm the substitution between ETFs and tradi-tional investment funds over 2007-2017, in particular in the first years of this time period.
Exhaled breath gas sensing using pristine and functionalized WO3 nanowire sensors enhanced by UV-light irradiation
- Tarik Saidi
- Dariusz Palmowski
- Sylwia Babicz-Kiewlicz
- Tesfalem Welearegay
- Nezha El Bari
- Radu Ionescu
- Janusz Smulko
- Benachir Bouchikhi
2018 Pełny tekst SENSORS AND ACTUATORS B-CHEMICAL
The development of advanced metal-oxide-semiconductor sensing technologies for the detection of Volatile Organic Compounds (VOCs) present in exhaled breath is of great importance for non-invasive, cheap and fast medical diagnostics. Our experimental studies investigate the effects of operating temperature selection and UV-light irradiation on improving the response of WO3 nanowire sensors towards exhaled breath exposure. Herein, six WO3 nanowire sensors (both pristine and doped with a range of metal nanoparticles such as Pt, Au, Au/Pt, Ni and Fe) were synthesised via Aerosol-Assisted Chemical Vapour Deposition (AACVD) and characterized by means of Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX-ray). Breath measurements were performed in the dark and under UV-light irradiation at various sensor operating temperatures. The results demonstrate that UV-light irradiation combined with the optimisation of the sensors’ operating temperature can greatly enhance the sensors’ responses towards breath exposure.
Expectation-Maximization Model for Substitution of Missing Values Characterizing Greenness of Organic Solvents
- Gabriela Łuczyńska
- Francisco Pena-Pereira
- Marek Tobiszewski
- Jacek Namieśnik
2018 Pełny tekst MOLECULES
Organic solvents are ubiquitous in chemical laboratories and the Green Chemistry trend forces their detailed assessments in terms of greenness. Unfortunately, some of them are not fully characterized, especially in terms of toxicological endpoints that are time consuming and expensive to be determined. Missing values in the datasets are serious obstacles, as they prevent the full greenness characterization of chemicals. A featured method to deal with this problem is the application of Expectation-Maximization algorithm. In this study, the dataset consists of 155 solvents that are characterized by 13 variables is treated with Expectation-Maximization algorithm to predict missing data for toxicological endpoints, bioavailability, and biodegradability data. The approach may be particularly useful for substitution of missing values of environmental, health, and safety parameters of new solvents. The presented approach has high potential to deal with missing values, while assessing environmental, health, and safety parameters of other chemicals.
Expedite EM-driven generation of Pareto-optimal trade-off curves for variable-turn on-chip inductors
- Sławomir Kozieł
- Piotr Kurgan
2018 IET Microwaves Antennas & Propagation
This work presents a novel approach to computationally efficient Pareto front identification for variable-turn on-chip inductors. The final outcome is a set of solutions that correspond to the best trade-offs between conflicting design objectives. Here, we consider minimising inductor area and, simultaneously, maximising its quality factor, while maintaining a specified inductance value at a given operating frequency. As opposed to the typically used population-based metaheuristics requiring massive computational resources to generate the entire Pareto front in a single algorithm run, the proposed method reduces the number of necessary structure evaluations by exploiting a point-by-point strategy for determining the consecutive trade-off designs. The original design problem is a mixed-integer task involving integer and non-integer variables (here, the number of inductor windings and its geometry parameters). For the sake of computational efficiency, we develop a separate kriging interpolation model for each considered case of winding turns, and use it, instead of expensive electromagnetic simulations, to obtain the initial Pareto fronts. The non-dominated part of the concatenated initial Pareto sets is subsequently elevated (accuracy-wise) to the level of an electromagnetic analysis by means of a response correction technique. Our considerations are illustrated using a 3.5-nH variable-turn on-chip inductor realised in 65-nm CMOS technology.
Expedited Design Closure of Antennas By Means Of Trust-Region-Based Adaptive Response Scaling
- Sławomir Kozieł
- Unnsteinsson Sigmar
2018 Pełny tekst IEEE Antennas and Wireless Propagation Letters
In the letter, a reliable procedure for expedited design optimization of antenna structures by means of trust-region adaptive response scaling (TR-ARS) is proposed. The presented approach exploits two-level electromagnetic (EM) simulation models. A predicted high-fidelity model response is obtained by applying nonlinear frequency and amplitude correction to the low-fidelity model. The surrogate created this way is iteratively rebuilt and optimized within the trust region framework. Utilization of the correlations between the EM models of various fidelities allows for significant reduction of the design optimization cost. The operation and performance of the algorithm are demonstrated using a dual-band patch antenna optimized for several scenarios. Comparative study reveals computational benefits of TR-ARS over direct optimization of the high-fidelity EM model. Reliability of the optimization process is further confirmed by experimental validation of the fabricated antenna prototypes.
Experience Based Decisional DNA (DDNA) to Support Sustainable Product Design
- Muhammad Ahmed
- Cesar Sanin
- Edward Szczerbicki
2018
This paper presents the idea of providing engineering design knowledge to designers working on sustainable product design and development process. The new product development process often requires significant amount of design knowledge which can be saved and recalled by designers during the design process. This knowledge is very important for successful sustainable product development as it can include material selection, product geometric features and process parameters, etc. This paper presents a decision support technique for recalling engineering design knowledge which can be useful for small and medium enterprises (SMES) involved in new product design and development. Proposed system is based on smart knowledge management technique called Set of Experience Knowledge Structure (SOEKS) and Decisional DNA. The SOEKS is a flexible and structured knowledge representation structure used to gain and store the experiential knowledge. The article includes a case study explaining the presented approach. Decision-making in industrial design will benefit from this study, as it includes capturing, storing and reusing of experience and knowledge of engineering design processes.
Experience-Based Decisional DNA (DDNA) to Support Product Development
- Edward Szczerbicki
- Muhammad Ahmed
- Cesar Sanin
2018 Pełny tekst CYBERNETICS AND SYSTEMS
Knowledge and experience are important requirements for product development. The aim of this paper is to propose a systematic approach for industrial product development. This approach uses smart knowledge management system comprising of Set of Experience Knowledge Structure and Decisional DNA (DDNA) along with Virtual Engineering Tools (Virtual engineering object, Virtual engineering process, and Virtual engineering factory). This system provides a new direction to researchers working on product development, especially designers and manufacturers. It will reduce their communication gap by allowing them to work on the same platform. The proposed system adopts an early consideration of manufacturing issues. Therefore, it can shorten product development cycle time, minimize overall development cost, and ensure a smooth transition into production. The proposed system is dynamic in nature because it updates itself after every time a new decision related to product development activity is made. Product development process can be performed systematically and efficiently by using this system as it stores knowledge of experiences of different activities.
Experimental and comparative study on the two-phase pressure drop of air-water mixture in U-bend and straight pipe annuli
- Rafał Andrzejczyk
- Tomasz Muszyński
2018 Pełny tekst Journal of Physics : Conference Series
In this paper, the experimental and theoretical analysis of pressure drop in singlephase and two phase-flow were presented for straight and U-bend smooth tube annulus and tube annulus with wire coil insert. Experiments for various boundary conditions were performed. In case of U-tube and straight tube with and without turbulator, tests were made for the water-water and air-water systems. The study covered a wide measuring range, i.e. Vw = 9*10-5-8.87*10-6 m3/s - for water, and Va=5.55*10-5 m3/s.-for air. The test elements were made from a copper pipe with an external diameter of 10 mm and 18 mm and wall thickness 1 mm. The helicoidal vortex generator was made from brass wire with a diameter of 2.4 mm, coil diameter 13 mm and pitch 11 mm. For these geometries, the values of pressure drop and heat flux were determined. Obtained experimental results were compared with correlations from literature. The best coherence with database were obtain for Lockhart-Martinelli and Sugawar et al. models for twophase flow regime.
Experimental and numerical investigations of concrete behaviour at meso-level during quasi-static splitting tension.
- Jan Suchorzewski
- Andrzej Tejchman-Konarzewski
- Michał Nitka
2018 THEORETICAL AND APPLIED FRACTURE MECHANICS
Artykuł omawia wyniki numeryczne dotyczące pękania betonu uzyskane stosując metodę elementów dyskretnych. Dwuwymiarowe obliczenia wykonano dla próbek betonowych podczas rozłupywania. Beton został opisany jako model 4-fazowy. Mikrostruktura betonu odpowiadała zdjęciom tomograficznym. Zbadano wpływ warunków brzegowych na proces pękania. W obliczeniach zwrócono uwagę na porzebieg zjawisk mikrostrukturalnych przebieg pękania. Wyniki numeryczne zostały porównane z wynikami doświadczalnymi. Uzyskano b. dobra zgodność między wynikami numerycznymi i doświadczalnymi.
EXPERIMENTAL AND NUMERICAL VALIDATION OF THE IMPROVED VORTEX METHOD APPLIED TO CP745 MARINE PROPELLER MODEL
- Przemysław Król
- Krzysztof Tesch
2018 Pełny tekst Polish Maritime Research
The article presents a numerical analysis of the CP745 marine propeller model by means of the improved vortex method and CFD simulations. Both numerical approaches are validated experimentally by comparing with open water characteristics of the propeller. The introduced modification of the vortex method couples the lifting surface approach for the propeller blades and the boundary element method for the hub. What is more, a simple algorithm for determination of the propeller induced advance angles is established. The proposed modifications provide better results than the original version of the vortex method. The accuracy of the improved method becomes comparable to CFD predictions, being at the same time a few hundred times faster than CFD