2019 - Repozytorium publikacji - Politechnika Gdańska

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FIBRE-OPTIC SENSOR FOR SIMULTANEOUS MEASUREMENT OF THICKNESSAND REFRACTIVE INDEX OF LIQUID LAYERS
- Marcin Marzejon
- Katarzyna Karpienko
- Adam Mazikowski
- Małgorzata Szczerska
2019 Pełny tekst Metrology and Measurement Systems
In this paper, we present a fibre-optic sensor for simultaneous measurement of refractive index and thickness of liquid layers. We designed an experimental low-coherence setup with two broadband light sources and an extrinsic fibre-optic Fabry–Pérot interferometer acting as the sensing head. We examined how the refractive index of a liquid film and its thickness affect spectrum at the output of a fibre-optic interferometer. We performed a series of experiments using two light sources and only one sensing head. The spectra were collected in ranges of 1220÷1340 nm and 1500÷1640 nm. The obtained results show that using two spectra recorded simultaneously for two wavelength ranges enables to determine thickness in a range of 50÷500 µm, and refractive index of a liquid film in a range of 1:00÷1:41 RIU using only one sensing head.
Fighting Administrative Corruption with Digital Government in Sub-Saharan Africa
- Yelkal Walle
- Tomasz Janowski
- Elsa Estevez
2019 Pełny tekst
Administrative corruption is a pervasive problem and a major threat to economic and social development around the world, especially in Sub-Saharan Africa which lags behind other regions in various development indicators and is seen as one of the most corrupt regions globally. This paper examines a hypothesis that digital government – the use of digital technology to transform public administration organizations and their relationships with citizens, businesses and each other – helps reduce administrative corruption in Sub-Saharan Africa. To this end, the paper relates the United Nation’s e-Government Development Index (EDI) and the Transparency International’s Corruption Perception Index (CPI) for 45 countries in the region in the period from 2012 to 2016, performing linear regression with EDI as an independent and CPI as a dependent variable. The estimated results show that the effects of digital government adoption on corruption reduction are statistically significant, with 37% of corruption reduction due to digital government development. The paper further explores the nature of this relationship using the case of Ethiopia, whose performance according to the EDI and CPI indexes improved slightly over the 2012-2016 period. As part of this case, the paper examines common applications such as e-procurement or e-tax that cut horizontally across ministries. Our findings suggest that the adoption of digital government has the potential for reducing administrative corruption in Sub-Saharan Africa but realizing such potential require strengthening of law enforcement and anti-corruption institutions, and political will.
Filozofia sieci 5G - radioinformatyka i wirtualizacja. Część 2. Wirtualny system 5G.
- Sławomir Gajewski
- Małgorzata Gajewska
2019 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
Przedstawiono najważniejsze właściwości sieci 5G z punktu widzenia istoty jej działania. Uporządkowano najistotniejsze pojęcia służące do opisu sieci 5G, zwłaszcza w kontekście rozwiązań softwarowych, wirtualizacji sieci oraz jej architektury fizycznej i funkcjonalnej. Wprowadzono i zdefiniowano wiele pojęć wynikających z nowej ery rozwoju radiokomunikacji, w tym pojęcie radioinformatyki, systemu radioinformatycznego, sieci radioinformatycznej. Uporządkowano i zdefiniowano główne elementy architektury sieci 5G zgodnie z przebiegiem standaryzacji oraz wskazano sposób integracji sieci 5G z 4G. Pierwsza część artykułu pt. Radioinformatyczny system 5G dotyczy w szczególności nowej nomenklatury koniecznej do przyjęcia w radiokomunikacji. Część druga pt. Wirtualny system 5G będzie natomiast dotyczyła problemu wirtualizacji w sieci 5G.
Finding small-width connected path decompositions in polynomial time
- Dariusz Dereniowski
- Dorota Osula
- Paweł Rzążewski
2019 Pełny tekst THEORETICAL COMPUTER SCIENCE
A connected path decomposition of a simple graph $G$ is a path decomposition $(X_1,\ldots,X_l)$ such that the subgraph of $G$ induced by $X_1\cup\cdots\cup X_i$ is connected for each $i\in\{1,\ldots,l\}$. The connected pathwidth of $G$ is then the minimum width over all connected path decompositions of $G$. We prove that for each fixed $k$, the connected pathwidth of any input graph can be computed in polynomial-time. This answers an open question raised by Fedor V. Fomin during the GRASTA 2017 workshop, since connected pathwidth is equivalent to the connected (monotone) node search game.
First Copper(I) and Silver(I) Complexes Containing Phosphanylphosphido Ligands
- Aleksandra Ziółkowska
- Sandra Brauer
- Łukasz Ponikiewski
2019 Pełny tekst ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
Three new complexes with phosphanylphosphido ligands, [Cu4{μ2-P(SiMe3)-PtBu}4](1), [Ag4{μ2-P(SiMe3)-PtBu2}4](2) and [Cu{η1-P(SiMe3)-PiPr2}2]–[Li(Diglyme)2] (3) were synthesized and structurally characterized by X-ray diffraction, NMR spectroscopy, and elemental analysis. Complexes 1 and 2 were obtained in the reactionsof lithium derivative of diphosphane tBu2P-P(SiMe3)Li·2.7THF withCuCl and [iBu3PAgCl]4, respectively. The X-ray diffraction analysis revealed that the complexes1 and 2 present macrocyclic, tetramericform with Cu4P4and Ag4P4core. Complex 3 was prepared in thereaction of CuCl with a different derivative of lithiated diphosphane iPr2P-P(SiMe3)Li·2(Diglyme). Surprisingly, the X-ray analysis of 3 revealed that in this reaction instead of the tetramer the monomericform, ionic complex [Cu{η1-P(SiMe3)-PiPr2}2]–[Li(Diglyme)2] was formed.
First report on echinocandin resistant Polish Candida isolates
- Martyna Mroczyńska
- Anna Brillowska-Dąbrowska
2019 Pełny tekst Acta Biochimica Polonica
Purpose: Candida spp. are ranked as one of the four major causative agents of fungal infections. The number of infections caused by Candida species resistant to fluconazole, which is applied as the first line drug in candidiasis treatment, increases every year. In such cases the application of echinocandin is necessary. Echinocandin susceptibility testing has become a routine laboratory practice in many countries due to the increasing frequency of clinical failures during treatment with these drugs. Methods: We performed anidulafungin, micafungin and caspofungin susceptibility testing according to the microdilution broth method on 240 Candida isolates collected in Polish hospitals. Results: We identified 12 isolates resistant to all echinocandins within 240 examined isolates. Moreover, 6 of the examined samples were identified as rare Candida species and among them we observed very high echinocandin MIC values. Conclusion: Our research proves that in Poland there is a problem of echinocandin resistance. Moreover, we identified two species of Candida which are rare causative agents of human infections, and there was no reported incidence of such infections in Poland until now.
Flexural buckling and post-buckling of columns made of aluminium alloy
- Czesław Szymczak
- Marcin Kujawa
2019 EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
The paper concerns flexural buckling and initial post-buckling of axially compressed columns made of aluminium alloy described by the Ramberg-Osgood relationship. The non-linear differential equation of the problem is derived using the stationary total energy principle and the assumptions of classical beam theory within a finite range. The approximate analytical solution of the equation leading to the buckling loads and initial post-buckling equilibrium path is determined by means of the perturbation approach. Numerical examples dealing with simply supported and clamped I-columns are presented, the effect of the material non-linearity on the critical loads and initial post-buckling behaviour in comparison to linear one is discussed too. The analytical results are compared with the FEM solutions to present a good agreement.
Flood Security Strategy - Case Studies from Gdańsk Region
- Andrzej Lewandowski
- Piotr Kowalski
- Wojciech Szpakowski
2019
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Floodplain inundation Mapping using SAR Scattering Coefficient Thresholding and Observed Discharge Data
- Tomasz Berezowski
- Tomasz Bieliński
- Jakub Osowicki
2019 Pełny tekst
Inundation area time series are important for wetlands monitoring and hydrological model validation. This study is conducted in Biebrza floodplain, which is a natural wetland with complex inundation generation processes. In order to map 2014-2018 series of inundation in the floodplain we test our automatic thresholding method on Sentinel 1 data. The threshold value is optimized using correlation of the inundation area with observed discharge at the floodplain outlet. The inundation maps match well the MODIS 500m reflectance data used as a reference, whereas, the total inundated area per Sentinel 1 image match well the observed discharge pattern. Unfortunately, this approach was unable to identify inundation in remote parts of the floodplain, what may have few reasons and needs further investigation.
Flow Boiling in Minigap in the Reversed Two-Phase Thermosiphon Loop
- Michał Klugmann
- Paweł Dąbrowski
- Dariusz Mikielewicz
2019 Pełny tekst ENERGIES
The paper presents the results of experimental investigations of a model of a heat exchanger featuring a minigap, which is perceived as an evaporator for an inverted thermosiphon. The system works with a single component test fluid. The tested evaporator generates pumping power in the test loop in a way similar to the mammoth pump. The tests regarded a module of the heat exchanger, consisting of a hot leg and a cold leg with the width by the length of 0.1 × 0.2 m, heated by a uniform heat flux. In the tests, the minigaps of 1, 2 and 3 mm were formed. Two fluids, namely, distilled water and ethanol, were tested in the facility. Two-phase flow structures for both working fluids and various operational parameters, together with comprehensive visualization material, are presented. The specifics of pressure changes and its influence on operating parameters and flow structure are discussed.
Flow maldistribution and its mitigation in mini heat exchangers
- Paweł Dąbrowski
- Michał Klugmann
- Dariusz Mikielewicz
2019
In the present paper, a detailed numerical investigation has been carried out to analyze the flow maldistribution in 50 parallel 1 mm x 1 mm rectangular minichannels and 1 mm depth minigap section with rectangular, trapezoidal, triangular or concave mani-folds in Z-type flow configuration (16 different cases). The working medium was ethanol and the mass flow rate was 5×10-4 kg/s. Both sections was heated from the bottom side. Heat flux of 10 000 W/m2 and 5 000 W/m2 was applied to the minichannel and minigap section respectively. It provides an equal heat flow rate of about 50 W for both types of the sections. A novel approach for the mitigation of non-uniformity has been proposed introducing threshold at the entrance of the minigeometry section. The maldistribution coefficient can be reduced about twice in the minigap section or about three times in the minichannel section with the 0.5 mm threshold as compared to the conventional arrangement without threshold. Authors analyzed velocity profile and temperature profile over the heat exchanger’s surface. Reduction of maldistribution results in lower maximum temperature over the surface. The distribution is more uniform in minichannel section than in minigap section. This is due to a two-dimensional flow over a minigap in comparison to one-dimensional flow in channels. To obtain uniform distribution of fluid and hence uniform temperature profile, flow should be stabilized al-ready at the inlet manifold, at the entrance to the minichannel or minigap section.
Folate/homocysteine metabolism and lung cancer risk among smokers
- Anna Stanisławska-Sachadyn
- Joanna Borzyszkowska
- Michał Krzemiński
- Alicja Janowicz
- Rafał Dziadziuszko
- Jacek Jassem
- Witold Rzyman
- Janusz Limon
2019 Pełny tekst PLOS ONE
Background: Folate and homocysteine are involved in DNA synthesis and methylation processes, which are deregulated during carcinogenesis. Objectives: The aim of this study was to assess the relationship between folate/homocysteine concentrations, the functional polymorphisms of folate/homocysteine genes and lung cancer risk among cigarette smokers. Study design: The study included 132 lung cancer patients and 396 controls from northern Poland, matched by sex, age and smoking status. The median cigarette pack-years of smoking among both cases and controls was 30.0. Serum, red blood cell (RBC) folates and serum homocysteine concentrations were measured. The genotypes in selected polymorphic sites of the MTHFR, CBS, SHMT1, MTHFD1, MTRR, MTR, TYMS DHFR, TCN2, and SLC19A1 genes were determined. All study participants underwent scanning with low-dose computed tomography. Results: Serum folate concentrations above the median (> 17.5 nmol/l among the healthy controls) were associated with an increased lung cancer risk (odds ratio [OR], 1.54, 95% confidence intervals [CI], 1.04-2.29, P= 0.031). An analogous trend was observed when the population was analysed after subdivision according to RBC folate concentrations, that is, above a value of 506.5 nmol/l (OR, 1.53; 95% CI, 0.95-2.47; P=0.084). Additionally, in a subset of women, an increased risk of lung cancer development was associated with the SLC19A1 c.80AA genotype (c.80AA versus GG OR, 3.14; 95% CI, 1.32-7.46; P= P=0.010). Conclusion: These results suggest that, in the population consisting of heavy smokers, high folate levels add to the cancerogenic effect of smoking.
Follow the Light. Where to search for useful research information
- Karolina Zielińska-Dąbkowska
2019 Pełny tekst ARC Lighting In Architecture
Architectural Lighting Design (ALD) has never been a standalone professional discipline. Rather, it has existed as the combination of art and the science of light. Today, third generation lighting professionals are already creatively intertwining these fields, and the acceleration in scientific, technological and societal studies has only increased the need for reliable multidisciplinary information. Therefore, a thorough re-examination of all aspects of ALD and how it relates to those particular changes is an urgent necessity. Further research is required to develop a new body of knowledge about ALD so that lighting professionals can improve their expertise in the field and receive better remuneration for their complex work. In the near future, we should be aiming for professional recognition as experts and join other recognised professions such as: architects, doctors, dentists, lawyers, engineers etc. While lighting designers (LD) need to constantly update and reexamine their knowledge, they face two dilemmas. First, WHERE should they search to obtain useful information on lighting in related fields? And secondly, HOW should they successfully evaluate the viability of this information in a time of “Google-isation”, Wikipedia, “lobbying” and data manipulation.
Force transfer and stress distribution in short cantilever deep beams loaded throughout the depth with a various reinforcement
- Anna Kopańska
- Krystyna Nagrodzka-Godycka
2019
Deep beams used as the main reinforced concrete structural elements which taking over the load and stiffening construction are often found in high-rise buildings. The architecture of these buildings is sometimes sophisticated and varied, arouse the admiration of the majority of recipients, and thus causing an engineering challenge to correctly design the structural system and force transfer. In such structures is important to shape the reinforcement in order to make the best use of reinforcing steel for taking over the load and minimize the crack widths. Despite the wide use of these elements, they are still not covered by the relevant design codes. In the current technical literature there is little information on the dimensioning of reinforced concrete cantilever deep beams or deep beams with overhangs and only few based on experimental research. This paper presents the results of experimental investigations of two reinforced concrete cantilever deep beams with shear slenderness lk / H = 0.3 under static load distributed on the entire height. The research elements were part of the spatial reinforced concrete deep beam systems, consisting of a transversal deep beam and suspended on it the longitudinal deep beam with cantilever. Reinforced concrete deep beam joints had various reinforcements. The article presents results on steel effort and force distribution in the reinforcement of short cantilever deep beam indirectly loaded. The effectiveness of the mixed reinforcement in both tested cantilever deep beams, as referred to the design recommendation proposed in the published papers is also verified. © Federation Internationale du Beton (fib) - International Federation for Structural Concrete, 2019.
FORECASTING EXCHANGE RATES IN THE PROCESS OF THE ASSESSMENT OF CONSUMER RISK BANKRUPTCY IN CENTRAL EUROPE
- Tomasz Korol
2019
This paper focuses on the issue of forecasting the fluctuation of exchange rates as part of the early warning system against the risk of consumer bankruptcy. The author identified the main macroeconomic factors affecting the level of bankruptcies for households in Poland. The fluctuation of exchange rates, which directly affects the deterioration of the economic situation of borrowers who have opened credit accounts in a foreign currency and indirectly affects the cost of living of all consumers in the country, is one of the significant macroeconomic factors. That is why the main objective of the presented research is to investigate the effectiveness of fuzzy sets in predicting the volatility of two currency pairs (PLN/CHF and PLN/USD). The models created will be part of a system of models aimed at forecasting the risk of consumer bankruptcy in Poland. The results demonstrate the high predictive properties of fuzzy sets in forecasting the volatility of analyzed currency pairs.
Formalno-prawne uwarunkowania rozwoju mieszkalnictwa w Polsce w aspekcie eksploatacji mieszkalnych jednistek pływających
- Emilia Miszewska
- Maciej Niedostatkiewicz
2019
Artykuł zawiera analizę sytuacji prawnej obiektów jakimi są Domy Na Wodzie oraz konsekwencji jakie powodują dla właścicieli aktualne zapisy najważniejszych Ustaw z nimi związanych tzn.: ustawy Prawo budowlane, ustawy o gospodarce nieruchomościami, Kodeksu cywilnego oraz Prawa wodnego. W pracy opisano światowe trendy osadnictwa na wodzie i porównano do sytuacji mieszkalnictwa na wodzie w Polsce. Na podstawie doświadczeń innych krajów oraz w oparciu o przepisy krajowe, opracowano i zaproponowano autorską definicję dla Domów Na Wodzie, (DNW) nazwanych przez autorów Mieszkalnymi Jednostkami Pływającymi (MJP). Ponadto podjęto próbę usystematyzowania wymagań i rozwiązań części problemów formalno-prawnych jakie w fazie eksploatacji dotyczą właścicieli MJP.
Formation of Protein Networks between Mucins: Molecular Dynamics Study Based on the Interaction Energy of the System
- Natalia Kruszewska
- Piotr Bełdowski
- Piotr Weber
- Steven Yuvan
- Marcin Drechny
- Marcin Kośmieja
2019 Pełny tekst ENERGIES
Molecular dynamics simulations have been performed for a model aqueous solution of mucin. As mucin is a central part of lubricin, a key component of synovial ﬂuid, we investigate its ability to form cross-linked networks. Such network formation could be of major importance for the viscoelastic properties of the soft-matter system and crucial for understanding the lubrication mechanism in articular cartilage. Thus,the inter- and intramolecular interaction energies between the residues of mucin are analyzed. The results indicate that the mucin concentration signiﬁcantly impacts its cross-linking behavior. Between 160 g/L and 214 g/L, there seems to be a critical concentration above which crowding begins to alter intermolecular interactions and their energies. This transition is further supported by the mean squared displacement of the molecules. At a high concentration, the system starts to behave subdiffusively due to network development. We also calculate a sample mean squared displacement and p-variation tests to demonstrate how the statistical nature of the dynamics is likewise altered for different concentrations.
Fotokatalityczna degradacja zanieczyszczeń środowiskowych
- Joanna Mioduska
- Anna Zielińska-Jurek
- Jan Hupka
2019 Nowa Energia
Fotokataliza uznawana jest za metodę z rosnącym potencjałem do usuwania zanieczyszczeń organicznych i nieorganicznych - zarówno z fazy wodnej, jak i gazowej. Liczba publikacji z ostatnich pięciu lat związana z tematyką fotokatalizy osiąga ponad 4000 rocznie, wg bazy danych Web of Science (2019 r.). Szczególny potencjał fotokatalizy tkwi w możliwości usuwania zanieczyszczeń uporczywie zalegających w środowisku, których źródłem są ścieki przemysłowe i komunalne.
Fractional Order Circuit Elements Derived from Electromagnetism
- Tomasz Stefański
- Jacek Gulgowski
2019
In this paper, derivations of fractional-order (FO) circuit-element equations from electromagnetism are presented. Whilst many papers are devoted to FO modelling of electrical circuits, there are no strong foundations for such an approach. Therefore, we investigate relations between the FO electromagnetism and the FO circuit theory. Our derivations start from quasi-static (QS) approximations of Maxwell's equations in media with FO constitutive relations. Hence, FO lumped-element equations are derived which are supported by an approximate applicability condition. If the FO capacitor/inductor satisfies the derived condition, then the energy of the magnetic/electric field is negligible in comparison to the energy of the electric/magnetic field in the considered FO element. Then, we demonstrate that FO lumped-element parameters can be derived assuming the equality of electromagnetic power flowing into the circuit element and calculated as the current and voltage product. The obtained results support researchers and engineers employing FO modelling in electrical and electronics engineering.
Fracture evolution in concrete compressive fatigue experiments based on X-ray micro-CT images
- Łukasz Skarżyński
- Ireneusz Marzec
- Andrzej Tejchman-Konarzewski
2019 Pełny tekst INTERNATIONAL JOURNAL OF FATIGUE
Artykuł omawia ewolucje pękania w betonie podczas cyklicznego ściskania betonu. Przestrzenną ewolucję pękania zobrazowano stosując mikro-tomograf rentgenowski. Zdjęcia wykonano dla różnych cykli zmęczeniowych. Wyniki porównano z testami monotonicznymi. Jakościowa ewolucja objętości pękania ze wzrostem zmęczeniowego zniszczenia pokazała silnie nieliniowy kształt.