2019 - Repozytorium publikacji - Politechnika Gdańska

Pokaż publikacje z roku

Publikacje z roku 2019

Pokaż wszystkie

Maritime Communication and Sea Safety of the Future - Machnine-type 5G Communication Concept
- Małgorzata Gajewska
2019 Pełny tekst Zeszyty Naukowe Akademii Marynarki Wojennej
The article presents the concept of a system based on 5G network and M2M communication increasing maritime safety. Generally, the focus was on presenting a proposal for a hierarchical, hybrid, cooperative system with M2M communication coordinated with BAN networks. The possi-ble applications of M2M communication at sea were also presented.
Maritime heritage of small port towns of the Polish coast
- Karolina Krośnicka
2019 PORTUSPlus
The article describes problems of the gradual disappearance of real maritime heritage in small Polish port cities. The maritime heritage of small port cities was shaped by coastal processes and urban historical conditions what has led to creation of specific types of landscapes. Special architectural objects of the post-port heritage of small ports of the Polish coast are hydrotechnical constructions (i.e. breakwaters, quays), buildings related to the technical support of ports (masters and bosuns’ offices, SAR buildings, lighthouses), buildings related to the transhipment and shipbuilding activities of ports (warehouses and hangars, silos). Due to the strong tourist pressure, these facilities should be given special attention.
Market knowledge and new product performance: the mediating effects of new product performance
- Dariusz Dąbrowski
2019 Pełny tekst Journal of Business Economics and Management
Market knowledge is recognised as an important predictor of new product performance, which existing studies have proven. However, a missing link in this relationship is creativity, and specifically, as a natural process in product innovation. This study aims to examine a model that includes two mediating mechanisms between market knowledge scope and two new product outcomes, respectively: a new product’s competitive advantage and its commercial success. In both cases two mediators are used that represent dimensions of creativity – i.e. a product’s meaningfulness and novelty. The model was tested on a sample of 374 Polish medium-high- and high-technology companies using structural equation modelling. The results indicated that market knowledge is transferred to both new product outcomes through new product creativity, albeit somewhat differently. The first mediating mechanism, which explains the factor of competitive advantage, operates only through the indirect effects of both the product’s meaningfulness and its novelty. The second mechanism works directly, through the market knowledge’s effect on commercial success, as well as indirectly, through product meaningfulness. Subsequently, theoretical and managerial implications as well as indications for future research are provided based on these findings.
Market orientation and hotel performance: The mediating effect of creative marketing programs
- Dariusz Dąbrowski
- Magdalena Brzozowska-Woś
- Edyta Gołąb-Andrzejak
- Agnieszka Firgolska
2019 Pełny tekst Journal of Hospitality and Tourism Management
This work investigates the indirect effects between market orientation and hotel performance through creative marketing programs. The focus is on exploring the indirect effects between 1) customer orientation, competitor orientation, and cross-functional integration; and 2) hotel financial performance through two aspects of creative marketing programs, namely, novelty and meaningfulness. Through an empirical analysis using structural equation modeling, we discovered four mediation phenomena in the hotel industry: customer orientation positively correlates to a hotel's financial performance through the meaningfulness and novelty of marketing programs, but competitor orientation and cross-functional integration contribute to the hotels' performance only via the meaningfulness of such programs. Furthermore, it was observed that customer orientation plays the most important role in market orientation, in terms of how well a hotel performs. These findings are used to discuss managerial implications and future research directions.
Markowitz’s portfolio theory – optimal length of estimation window for gold and the biggests companies on the Warsaw Stock Exchange
- Marcin Potrykus
2019 Pełny tekst PRACE NAUKOWE UNIWERSYTETU EKONOMICZNEGO WE WROCŁAWIU
The following article is dedicated to the construction of an investment portfolio consisting of 3 investments from the Polish capital market found in the WIG20 index and from investment in gold. The purpose of the study was to determine the optimal length of the estimation window for building a portfolio with minimal risk and maximum efficiency. The length of the estimation window was also assessed in terms of the rate of return and the maximum cumulative loss. Data from 2017 was used to build the portfolio, and the weightings determined for the portfolio based on these data were evaluated using data from 2018 (from January to October). Based on the research, it was found that the optimal length of the estimation window ranges from 144 to 160 daily observations from the past. However, depending on the investment objective (risk minimization or maximization of efficiency) and the characteristics describing the portfolio, other lengths of the estimation window may also be appropriate.
Mass Spectrometry-Based Direct Analytical Techniques
- Renata Marcinkowska
- Klaudia Pytel
- Bożena Zabiegała
2019
Direct analysis of samples is considered as one of the most environmentally sustainable solutions in analytical chemistry. In the ideal case, such solutions do not require sample preparation and analytes separation steps, therefore do not consumpt harmful substances (or consumpt only minimum amounts of them) and do not generate hazardous waste. Technical solutions for direct analysis also offer miniaturized and field-portable analyzers or allow for remote measurements, posing no risk for human health. Among available direct analytical techniques, mass spectrometry-based solutions evolved tremendously in recent years and therefore gained a huge popularity, which fostered their implementation in a wide range of areas of interest. In this chapter, MS-based direct analytical techniques providing environmentally friendly analysis of samples of even complex matrix composition were discussed. They were characterized in the context of principles of measurement, advantages, and limitations as well as fields of their applications. Also, important aspects of their applicability were highlighted. Finally, some future trends in direct analysis field were indicated.
Mass transfer in Spinning Fluids Reactor — Measurement and prediction
- Przemysław Wojewódka
- Robert Aranowski
- Christian Jungnickel
2019 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
Specific mass transfer area (a) and overall volumetric mass transfer coefficient (kLa) are mass transfer parameters commonly used in the description and comparison of various chemical reactors’ constructions. Determination of these was performed for Spinning Fluids Reactor (SFR). Sodium sulfite oxidation in the presence of cobalt ion catalyst was used for the determination of a and kLa. The a and kLa were successful predicted. Overall, the a and kLa is one order of magnitude larger than any gas liquid contactor to date.
Matematyczne spojrzenie na reakcje chemiczne
- Agnieszka Bartłomiejczyk
2019 Delta
Modelowanie matematyczne jest pewnego rodzaju sztuką opisywania świata — zarówno w skali mikro jak i makro — za pomocą równań matematycznych (równań różniczkowych, różnicowych czy stochastycznych).
MATHEMATICAL MODELING OF FLOOD MANAGEMENT SYSTEM IN THE CITY OF GDAŃSK, ORUŃSKI STREAM CASE STUDY
- Tomasz Kolerski
- Dominika Kalinowska
2019 Pełny tekst Acta Scientiarum Polonorum Formatio Circumiectus
Aim of the study This study analyses the efficiency of flood protection in a small urban catchment, based on a system of small reservoirs. Material and methods To assess the flood routing and surge reduction, a mathematical model of the river catchment was implemented. This was a lumped hydrological model, based on the SCS-CN method. Channel routing was performed, using kinematic wave equation. The sub-catchments have been determined based on the topographic maps and rain sewage systems. In the paper, the hydrological model of the water system of Potok Oruński (Oruński Stream) is presented with particular focus on the new and renovated retention structures. Hydrological modelling system of HEC HMS was used to simulate the catchment’s response to precipitation. Thanks to the recently established monitoring system of the Oruński Stream, it was possible to calibrate and validate the model. Single rain episode from April 2018 was used to perform model calibration, proving its high compatibility. The calibrated model was then used to reproduce the flood surge of July 2001, using historical catchment data. The peak discharge demonstrated a need for additional retention in the studied catchment. Theoretical scenarios were also modelled. The precipitation volume was calculated based on the IFS. As a worst-case scenario, the rain producing the most intense surface runoff was included. In all simulations, historical conditions as well the current state (2018) and projected further urbanisation of the catchment were taken into consideration. Results and conclusions Results of the study have shown reduction of the historical flood surge from July 2001 by nearly 60% when all existing flood protection systems were used.
Mathematical modeling of hydrogen production performance in thermocatalytic reactor based on the intermetallic phase of Ni3Al
- Janusz Badur
- Michał Stajnke
- Paweł Ziółkowski
- Paweł Jóźwik
- Zbigniew Bojar
- Piotr Ziółkowski
2019 Pełny tekst Archives of Thermodynamics
The main goal of the following work is to adjust mathematical modelling for mass transfer, to specific conditions resulting from presence of chemical surface reactions in the flow of the mixture consisting of helium and methanol. The thermocatalytic devices used for decomposition of organic compounds incorporate microchannels coupled at the ends and heated to 500 oC at the walls regions. The results of the experiment were compared with CFD calculations to calibrate the constants of the model’s UDFs (User Defined Functions). These extensions allow to transform the calculations mechanisms and algorithms of commercial codes adapting them for the microflows cases and increased chemical reactions rate on an interphase between fluid and solid, specific for catalytic reactions. Results obtained on the way of numerical calculations have been calibrated and compared with the experimental data to receive satisfactory compliance. The model has been verified and the performance of the thermocatalytic reactor with microchannels under hydrogen production regime has been investigated.
Mathematical Modeling of Ice Thrusting on the Shore of the Vistula Lagoon (Baltic Sea) and the Proposed Artificial Island
- Tomasz Kolerski
- Piotr Zima
- Michał Szydłowski
2019 Pełny tekst Water
Coastal lagoons are inland and shallow water bodies, separated from the ocean by a barrier. In cold regions, ice phenomena in shallow water coastal lagoons occur every winter season. Ice is predominantly formed on the surface due to density stratification and surface cooling. The ice dynamics in such areas are dominantly affected by winds. Water dynamics also cause ice movement, but due to the large areal scale of lagoons, the effect is usually limited to the direct vicinity of river estuaries. For open lagoons, which are connected to the sea by straits, tides will also cause significant movement of the ice inside the lagoon. Due to the limitation of ice outflow from a lagoon, ice fields will form ridges or hummocks on the shores. In this paper, the case of the Vistula Lagoon, located on the southern Baltic coast, is analyzed. Currently, the project of a new strait connecting the Baltic Sea with the Vistula Lagoon is in progress. As an effect of extensive dredging for the waterway to the port of Elblag, the material will be disposed of at a Confined Disposal Facility (CDF), which will form an artificial island. The island will be located on the western part of the lagoon, limiting the cross-section by about 20%. In consequence, ice cover pushed by winds blowing along the lagoon will create significant force action on the island banks. The DynaRICE mathematical model has been used to evaluate the ice dynamics and to determine the force produced by the ice on the coasts of the lagoon and the artificial island.
Mathematical models of process quality on the example of the bakery industry
- Radosław Drozd
- Jan Piwnik
2019 Aparatura Badawcza i Dydaktyczna
This article presents a new approach to quantitative dimensionless assessment of the efficiency and competitiveness of production processes. New concepts of process quality and relative product quality have been introduced. Process quality was expressed in vector and scalar. The process quality vector ono was expressed by the product of reliability by the vector from the sum of three components taking into account the composition of grammage repeatability and the minimum cost. Two new scalar measures of process quality as a quality vector module and the mixed product of three process base vectors are proposed. A new concept of relative product quality (WJP) was also highlighted. Separability and relationship of both concepts is presented. The assessment method is illustrated by calculations on the example of baking processes carried out at the bakery in the Pomeranian Voivodeship. The usefulness of robotization leading to a significant increase in process quality indicators has been demonstrated. New quantitative and vector measures of process quality have been developed that provide the opportunity to build technological, economic and organizational algorithms that lead to innovation and increase in the efficiency of production processes.
Matrix solid-phase dispersion (MSPD) as simple and useful sample preparation technique for determination of polybrominated diphenyl ethers (PBDEs) in dust
- Monika Śmiełowska
- Bożena Zabiegała
2019 ANALYTICA CHIMICA ACTA
In the present study a novel analytical procedure for the determination of polybrominated diphenylethers in dust samples was developed.The main aim of the research was the selection of the optimum conditions of the matrix solid-phasedispersion before thefinal determination of polybrominated diphenyl ethers in dust samples. In order toassess the best usefulness of this technique, a favourable ratio of sample amount to the mass ofdispersing sorbent, as well as the type of this sorbent used has been tested. The type of sorbentresponsible for additional purification (clean-up sorbent) of the extract during matrix solid-phasedispersion was also selected. Gas chromatography coupled with mass spectrometry will be used at thefinal determination step.Preliminary results indicate that the use of matrix solid-phase dispersion can be a promising alter-native to other time-consuming and multi-stage analytical procedures. The proposed method providedsatisfactory recoveries (76e119%) and limits of detection: 2.1e4.4 pg/mikrogram for tri-heptaBDE in linear rangeof 5e100 pg/mikrogram; 480 pg/mikrogrm for decaBDE in linear range of 500e2000 pg/mikrogram from only 0.05 g of a dustsample. Finally, the method was applied to study the content of selected polybrominated diphenyl ethersin real dust samples.
Maturity curve for estimating the in-place strength of high performance concrete
- Aleksandra Kuryłowicz-Cudowska
- Marzena Kurpińska
- Krzysztof Wilde
2019 Pełny tekst MATEC Web of Conferences
The paper presents the maturity curve for estimating the in-place early-age compressive strength of concrete. The development of appropriate maturity curve is a complex process. It is important to correctly determine the datum temperature and activation energy, which can be obtained in mortar tests. This paper describes an investigation of the accuracy of the maturity method to estimate the strength when different way to rate constant and maturity function are analysed. High performance concrete used for construction of extradosed bridge was tested. The developed curve was implemented to predict the concrete strength at three construction stages, in summer, autumn and early spring.
Mądre podejmowanie decyzji w sytuacjach problematycznych poprawiajace wybór rozwiązań
- Henryk Krawczyk
- Andrzej Targowski
2019
Przedstawiono klasyfikację problemów od precyzyjnie zdefiniowanych do intuicyjnie zrozumiałych. Dla tych drugich zaproponowano nowy model wyboru rozwiązań uwzględniający ocenę ich zalet i wad. Rozpatrzono zarówno indywidualne jak i zespołowe procedury podejmowania takich decyzji. Zasygnalizowano możliwości występowania nierozstrzygalnych sytuacji, które wymagają mądrych ludzkich działań. Sprowadzają się one do wyboru właściwej metody uzgadniania ocen analizowanych rozwiązań, jak też do otwartości pozwalającej na uwzględnienie w takiej ocenie wszystkich racjonalnych kontrargumentów. Podkreślono,ze świat wirtualny daje szanse na pozyskanie wiedzy o tego typu działaniach, co może ułatwić poznawanie ludzkiej madrości.
Measurement Stand and Methodology for Research of the Off-Body and Body-to-Body Radio Channels in WBANs with Different Diversity Schemes
- Sławomir Ambroziak
2019 Pełny tekst International Journal of Antennas and Propagation
The concept of an experimental test bed for system loss and channel impulse response measurements for off-body and body-to-body radio channels in wireless body area networks (WBANs) is fully described. The possible measurement scenarios that may occur in investigation of off-body and body-to-body channels are classified and described in detail. Additionally, an evaluation is provided of the standard and expanded uncertainties of the presented measurement stand and methodology. Finally, the exemplary results are presented and discussed, in order to point out the need for further investigations of different diversity schemes and their applications in WBANs.
Mechanical Properties of Aluminium Bracket Strengthening
- Andrzej Ambroziak
2019 Pełny tekst Archives of Civil Engineering
The aim of the research is laboratory investigation of aluminium brackets employed to fasten lightweight curtain walls to building facilities. Tensile loads perpendicular to end plates (vertical) were applied here. The author focused on the solutions intended to increase the load-carrying capacity of aluminium brackets applying the plain washer form A (DIN 125; ISO 7089), plain washer with an outer diameter about 3d (DIN 9021; ISO 7093) and additional cover plates (straps) in the location of bolt anchoring on the base plate. The aluminium brackets were tested on a steel base and concrete substrate. The flexibility of anchoring strongly affects the increase of the end plate middle point displacement and movable crosshead displacement.
Mechanical properties of the human stomach under uniaxial stress action
- Grzegorz Rotta
- Jarosław Kobiela
- Szymon Grymek
- Magdalena Karczewska-Wysocka
2019 Pełny tekst CURRENT SCIENCE
The aim of this study was to estimate the range of mechanical properties of the human stomach in order to use the collected data in numerical modelling of surgical stapling during resections of the stomach. The biomedical tests were conducted in a self-developed tensile test machine. Twenty-two fresh human stomach specimens were used for the experimental study of its general strength. The specimens were obtained from morbidly obese patients on whom sleeve gastrectomy was performed. Finally, data on mechanical properties of the stomach wall with detailed analysis of anatomical regions of the stomach have been presented.
Mechanical properties of two-stage concrete modified by silica fume
- Hakim Abdelgader
- Roman Fediuk
- Marzena Kurpińska
- Jamal Elkhatib
- G. Murali
- A.v. Baranov
- R.a. Timokhin
2019 Pełny tekst Magazine of Civil Engineering [ Инженерно-строительный журнал (Inzhenerno-stroitelnyy zhurnal) ]
Abstract. Two-stage concretes, despite the fact that they have proven themselves in various types of construction, have not been studied to the same extent as traditional heavy concretes. Therefore, the article developed the composition of frame concrete with various additives in the composition of the cement-sand mortar. A comparison of the mechanical characteristics of the developed compositions with the addition of silica fume (SF) and superplasticizer (SP) in various combinations. In addition, test specimens were prepared with combinations of water/cement ratios of 0.45, 0.55, and 0.85, and cement/sand ratios of 0.5, 1, and 1.5. A total of 36 mixtures were prepared, silica fume was introduced as a partial replacement of cement in the amount of 6 wt.%. And a superplasticizer equal to 1.2 % of the cement content was added to the water. Compressive strength tests on two-stage concrete cylinders were carried out in accordance with ASTM-C873 and ASTM-C943. Tensile strength was also tested on 3 samples of each composition in accordance with the procedure described in ASTM-C496/C496M. As a result, the development of the strength of two-stage concrete for 7, 28 and 120 days was studied. It was found that the overall compressive strength of the twostage concrete based on SF, SP and SF + SP was higher than in concrete without any additives. At the same time, the modified concrete has higher strength properties, because it provides better contact due to expansion, as well as by reducing the water-cement ratio in grout. The results obtained allow to design a cement-sand mortar capable of filling all the voids between the coarse aggregate, thereby creating a dense structure of two-stage concrete.
Mechanics of mesh implanted into abdominal wall under repetitive load. Experimental and numerical study
- Agnieszka Tomaszewska
- Izabela Lubowiecka
- Czesław Szymczak
2019 Pełny tekst JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS
There are a number of papers discussing medical and mechanical aspects of ventral hernia management. Despite intensive work on the problem understanding, recurrences of the sickness still happen too often. For that reason new aspects of the problem must be considered. In this paper, a change in the abdominal implant’s stiffness is discussed, which is caused by cyclic loading. Such loading influence abdominal implant e.g. while patient’s coughing or exercising. For the first time this stiffness change is quantitatively described for a selected knitted mesh. The influence of mesh stiffness changes on repaired hernia persistence is studied. Then, ex vivo experiments on a repaired hernia model under cyclic pressure loading are performed. Finally, numerical simulations of the experiments are made in which stresses and forces in the system are calculated. The two following cases are considered. In the first case, the mesh has its baseline stiffness, and in the second case, the mesh is preconditioned by former loading; thus, it is stiffened. Reaction forces at the mesh fixation points appear to be approximately two-fold higher in the second case than in the first case. That may be a reason for a fixation damage in operated hernia system. The results presented shed new light on the necessary strength of mesh fixation in the abdominal wall. They enlarge the state of the art on laparoscopic hernia management with the use of a synthetic implant.