2019 - Repozytorium publikacji - Politechnika Gdańska

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Storm petrels as indicators of pelagic seabird exposure to chemical elements in the Antarctic marine ecosystem
- Aneta Pacyna-Kuchta
- Dariusz Jakubas
- Anne Ausems
- Marcin Frankowski
- Żaneta Polkowska
- Katarzyna Wojczulanis-Jakubas
2019 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT
Data on trace element bioavailability in the south-polar marine ecosystem is still scarce, compared to that relating to temperate zones. Seabirds can be used as indicators of ecosystem health and sentinels of environmental pollution, constituting a link between marine and terrestrial environments. Here, we analysed the concentration of 17 elements (with special emphasis on mercury, Hg) in feathers of adults and chicks of two pelagic seabirds – the Wilson's storm petrel Oceanites oceanicus and the black-bellied storm petrel Fregetta tropica – breeding sympatrically in the maritime Antarctic. Since adult feathers are formed during the non-breeding period away from the breeding grounds, but down and body feathers of chicks grow at the breeding sites, we were able to evaluate the birds' exposure to contaminants at various stages of their annual life cycle and in various marine zones. We found that of the two studied species, adult black-bellied storm petrels had significantly higher mercury, selenium and copper levels (5.47 ± 1.61; 5.19 ± 1.18; 8.20 ± 0.56 μg g˗1 dw, respectively) than Wilson's storm petrels (2.38 ± 1.47; 1.81 ± 0.98; 2.52 ± 2.35 μg g˗1 dw, respectively). We found that Wilson's storm petrel chicks had a significantly different contaminant profile than adults. Arsenic, bismuth and antimony were detected exclusively in the chick feathers, and the Se:Hg molar ratio was higher in chicks than in adults. Our study also suggests considerable maternal transfer of Hg (to down feathers) in both species. As global contaminant emissions are expected to increase, birds inhabiting remote areas with sparse anthropogenic pollution can indicate the temporal trends in global contamination.
Strach przed nieznanym błędem
- Jarosław Wawer
2019 Elektronika dla wszystkich
Felieton popularnonaukowy dotyczący algorytmu genetycznego.
Stradar - Multimedia Dispatcher and Teleinformation System for the Border Guard
- Marek Blok
- Bartosz Czaplewski
- Sylwester Kaczmarek
- Jacek Andrzej Litka
- Marcin Narloch
- Maciej Sac
2019 Pełny tekst Zeszyty Naukowe Akademii Marynarki Wojennej
Security of national borders requires utilization of multimedia surveillance systems automatically gathering, processing and sharing various data. The paper presents such a system developed for the Maritime Division of the Polish Border Guard within the STRADAR project. The system, apart from providing communication means, gathers data, such as map data from AIS, GPS and radar receivers, videos and photos from camera or audio from phone calls and SMS messages, from multiple mobile units and stationary points located along the coastline. All gathered data can be visualized on a multidisplay by the personnel that can dynamically select presented data and configure form of presentation. The paper describes system functionalities, its hardware and software implementation, and presents results of acceptance tests that the system have recently passed.
Strategia działania przedsiębiorstw ciepłowniczych w warunkach konkurencji
- Waldemar Kamrat
2019 Pełny tekst Ciepłownictwo, Ogrzewnictwo, Wentylacja
W pracy przedstawiono główne uwarunkowania rozwoju przedsiębiorstw ciepłowniczych w powiązaniu do aktualnej sytuacji, ale także i perspektyw rozwoju w warunkach gospodarki rynkowej.
Strategies for mitigating nitrous oxide production and decreasing the carbon footprint of a full-scale combined nitrogen and phosphorus removal activated sludge system
- Ewa Zaborowska
- Xi Lu
- Jacek Mąkinia
2019 Pełny tekst WATER RESEARCH
Nitrous oxide (N2O) emitted from biological nutrient removal activated sludge systems contributes significantly to the total carbon footprint of modern wastewater treatment plants. In the present study, N2O production and emissions were experimentally determined in a large-scale plant (220,000 PE) employing combined nitrogen (N) and phosphorus (P) removal. As a modelling tool, the Activated Sludge Model 2d (ASM2d) was extended with modules describing multiple N2O production pathways and N2O liquid-gas transfers. The new model was calibrated and validated using the results of laboratory experiments and full-scale measurements. Different operational strategies were evaluated following the proposed model-based procedure. Heterotrophic denitrification was found to be the predominant pathway of N2O production under both anoxic and aerobic conditions. This behaviour could primarily be attributed to the predominant abundance of heterotrophic denitrifiers over nitrifiers. Simulations revealed that the optimal solution for minimizing liquid N2O production is to set the dissolved oxygen concentration in the aerobic zone from 1 to 2 mg O2/L and to enhance the mixed liquor recirculation rate (MLR) (> 500% of the influent flowrate) while not compromising effluent standards. Regarding the actual conditions, the potential reduction in the carbon footprint was estimated to be 10% by applying the proposed operational strategy. The results suggest that considerable improvements can be achieved without substantial upgrades and increased costs.
Strefa bliska anteny w zastosowaniach radiolokalizacyjnych
- Olga Błaszkiewicz
- Krzysztof Cwalina
- Paweł Tomasz Kosz
- Alicja Olejniczak
- Piotr Rajchowski
- Jarosław Sadowski
- Jacek Stefański
2019 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
W artykule omówiono problem nieliniowej zależności fazy pola elektrycznego od odległości w bezpośrednim sąsiedztwie anten nadajników stacji odniesienia w systemach radiolokalizacyjnych i radionawigacyjnych. Nieskompensowana nieliniowość, a nawet niemonotoniczność zależności fazy może powodować systematyczne błędy estymacji położenia obiektów. W niektórych rozwiązaniach wpływ tej nieliniowości może być widoczny nawet w odległościach wielokrotnie większych od przyjętej granicy strefy bliskiej anteny.
Strength parameters of polyester reinforced PVC coated fabric after short term creep loading in biaxial mode
- Krzysztof Żerdzicki
- Yago Moreno Jacomini
2019 Pełny tekst
This study addresses the analysis of tensile strength parameters of the technical fabric VALMEX, which is composed of two orthogonal polyester thread families (named the warp and fill) and both sides PVC coated. The material was firstly subjected to 48-hour biaxial creep loading with the equal stress level in both orthogonal directions of the fabric. The stress levels were established as follows: 4.6 kN/m, 10.4 kN/m, 16.4 kN/m, 22.4 kN/m, 28.4 kN/m, 34.4 kN/m. The samples after creep loading were left unloaded in la-boratory conditions for the subsequent 6 months and then subjected to biaxial tension till rupture. For all tests, the basic tensile properties of the fabric have been identified for the warp and weft directions separately. The evolution of parameters demonstrates how the level of biaxial material prestressing affects tensile strength properties of the VALMEX fabric.
Stress analysis of a strip under tension with a circular hole
- Ireneusz Kozera
- Violetta Konopińska-Zmysłowska
- Marcin Kujawa
2019 Pełny tekst AIP Conference Proceedings
The paper addresses stress analysis of a strip with a circular hole under uniform uniaxial tension based oncircumferential stress expressionρπ. Stresses are analyzed in the infinite-length strips under tension with holes, the ratioof the hole radiusa to the strip half-widthb is either equal to:κ =a/b = 0.1 orκ = 0.5. Circumferential stresses aredetermined in selected cross-sections of the strip. The stress diagrams display local stress concentration near the hole.The analytical solutions are compared with the numerical solutions the finite elements method (FEM), the latter using theABAQUS software due to variousκ ratios. The results show the maximum circumferential stress at hole boundary,affected by the ratio of the hole radius to the width of the strip.
Striving for spatial energy efficiency in dwelling complexes. Kształtowanie przestrzennej efektywności energetycznej w zespołach zabudowy mieszkaniowej.
- Julia Kurek
- Justyna Martyniuk-Pęczek
2019 Pełny tekst Środowisko Mieszkaniowe
The main aim of this article was to discover the key characteristics in shaping most rewarded eco- district complexes built respectively in temperate climate zone in respect to spatial energy efficiency and resilience principles. It was done through careful case studies, comparative analysis and juxtaposition of critical parameters related to spatial energy efficiency and resilience in chosen representative dwelling complexes. Due to the complexity and multitude instances of ecological dwelling complexes it was decided to set bounds to the defined criteria. The investigated examples were limited to following restrictions as location in moderate climate zone, implementing the pro-environmental solutions in accordance world-known energy and environmental assessment certifications. As a result, a reliable juxtaposition of design trends in temperate climate zone was provided, which was induced by the key spatial energy efficiency parameters. Furthermore, the remarks and future framework guidelines were made, concerning main fields of potential improvements in terms of spatial energy efficiency and resilience.
Strongly anisotropic surface elasticity and antiplane surface waves
- Victor Eremeev
2019 Pełny tekst PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
Within the new model of surface elasticity, the propagation of anti-plane surface waves is discussed. For the proposed model, the surface strain energy depends on surface stretching and on changing of curvature along a preferred direction. From the continuum mechanics point of view, the model describes finite deformations of an elastic solid with an elastic membrane attached on its boundary reinforced by a family of aligned elastic long flexible beams. Physically, the model was motivated by deformations of surface coatings consisting of aligned bar-like elements as in the case of hyperbolic metasurfaces. Using the least action variational principle, we derive the dynamic boundary conditions. The linearized boundary-value problem is also presented. In order to demonstrate the peculiarities of the problem, the dispersion relations for surface anti-plane waves are analysed. We have shown that the bending stiffness changes essentially the dispersion relation and conditions of anti-plane surface wave propagation.
Structural and spectroscopic analysis of a new family of monomeric diphosphinoboranes
- Anna Ordyszewska
- Natalia Szynkiewicz
- Emil Perzanowski
- Jarosław Chojnacki
- Aleksandra Wiśniewska
- Rafał Grubba
2019 Pełny tekst DALTON TRANSACTIONS
We present a series of amino- and aryl(diphosphino)boranes R2PB(R’’)PR’2, where R2P, R’2P = tBu2P, tBuPhP, Ph2P, Cy2P, and R’’ = iPr2N, Ph, which were obtained via the metathesis reaction of iPr2NBBr2 or PhBBr2 with selected lithium phosphides. The structures of isolated diphosphinoboranes were characterized in the solid state and in solution by means of X-ray diffraction and NMR spectroscopy, respectively. The utility of these P–B–P species as ligands for transition metal complexes was tested in the reaction with [(COD)PtMe2]. Moreover, we carried out DFT calculations to elucidate bonding interactions and philicity of the reactive centers as well as to analyze conformations of the studied species. Electronic and steric properties of substituents on P and B atoms were found to have a strong influence on the structures of the obtained compounds. Three main types of diphosphinoboranes were distinguished, based on the strength of P–B π-interaction within the molecule: (i) application of strong electron-donating substituents on P-atoms and electron-accepting phenyl groups on B atoms led to the structure with one double PvB and one single P–B bond and diverse planar and pyramidal geometry of phosphanyl groups; (ii) reduction of the donor ability of phosphanyl groups gave diphosphanylboranes with delocalized P–B–P π-interactions; (iii) introduction of amino groups with strong donor abilities on B atoms canceled P–B π-interactions and allowed compounds with two very long P–B bonds and two pyramidal phosphanyl groups to be obtained.
Structural and Thermo-Mechanical Properties of Poly(ε-caprolactone) Modified by Various Peroxide Initiators
- Marta Przybysz-Romatowska
- Aleksander Hejna
- Józef Haponiuk
- Krzysztof Formela
2019 Pełny tekst Polymers
The modification of poly(ε-caprolactone) (PCL) was successfully conducted during reactive processing in the presence of dicumyl peroxide (DCP) or di-(2-tert-butyl-peroxyisopropyl)-benzene (BIB). The peroxide initiators were applied in the various amounts of 0.5 or 1.0 pbw (part by weight) into the PCL matrix. The effects of the initiator type and its concentration on the structure and mechanical and thermal properties of PCL were investigated. To achieve a detailed and proper explication of this phenomenon, the decomposition and melting temperatures of DCP and BIB initiators were measured by differential scanning calorimetry. The conjecture of the branching or cross-linking of PCL structure via used peroxides was studied by gel fraction content measurement. Modification in the presence of BIB in PCL was found to effectively increase gel fraction. The result showed that the cross-linking of PCL started at a low content of BIB, while PCL modified by high DCP content was only partially cross-linked or branched. PCL branching and cross-linking were found to have a significant impact on the mechanical properties of PCL. However, the effect of used initiators on poly(ε-caprolactone) properties strongly depended on their structure and content. The obtained results indicated that, for the modification towards cross-linking/branching of PCL structure by using organic peroxides, the best mechanical properties were achieved for PCL modified by 0.5 pbw BIB or 1.0 pbw DCP, while the PCL modified by 1.0 pbw BIB possessed poor mechanical properties, as it was related to over cross-linking.
Structural changes of a simple peptide—Trpzip-1—in aqueous solutions and the corresponding hydration phenomena under the influence of temperature
- Piotr Bruździak
- Aneta Panuszko
- Barnaba Piotrowski
- Janusz Stangret
2019 JOURNAL OF MOLECULAR LIQUIDS
Trpzip-1, a simple β-hairpin, is a rare example of peptide with stable secondary structure and can be a convenient model to study temperature-related processes that potential prion or amyloid proteins undergo. Although its sequence is simple, the exact processes which the peptide undergoes in aqueous solutions are quite complex and not well understood. The selection of well-established experimental (DSC, FTIR) and theoretical methods allowed to describe, on the molecular level, the sequence of Trpzip-1 structural transitions. Our results we can indicate and explain peculiarities concerning initial oligomerization and two-step denaturation mechanism. The analysis of water structure surrounding the peptide at various temperatures reveals that the hydration sphere of its monomeric, oligomeric, and unfolded states is enhanced in comparison to the “bulk” water, but in each case, it exhibits different properties. Our observations may be of general nature in terms of structural changes of peptides and accompanying phenomena in solutions.
Structural, functional, and stability change predictions in human telomerase upon specific point mutations,
- Umesh Kalathiya
- Monikaben Padariya
- Maciej Bagiński
2019 Pełny tekst Scientific Reports
Overexpression of telomerase is one of the hallmarks of human cancer. Telomerase is important for maintaining the integrity of the ends of chromosomes, which are called telomeres. A growing number of human disease syndromes are associated with organ failure caused by mutations in telomerase (hTERT or hTR). Mutations in telomerase lead to telomere shortening by decreasing the stability of the telomerase complex, reducing its accumulation, or directly affecting its enzymatic activity. In this work, potential human telomerase mutations were identified by a systematic computational approach. Moreover, molecular docking methods were used to predict the effects of these mutations on the affinity of certain ligands (C_9i, C_9k, 16A, and NSC749234). The C_9k inhibitor had the best binding affinity for wild-type (WT) telomerase. Moreover, C_9i and C_9k had improved interactions with human telomerase in most of the mutant models. The R631 and Y717 residues of WT telomerase formed interactions with all studied ligands and these interactions were also commonly found in most of the mutant models. Residues forming stable interactions with ligands in molecular dynamics (MD) were traced, and the MD simulations showed that the C_9k ligand formed different conformations with WT telomerase than the C_9i ligand.
Structural investigations of niobium-doped bioactive calcium-phosphate glass-ceramics by means of spectroscopic studies
- Agnieszka Witkowska
- Wojciech Korzeniewski
2019
Synthetic calcium-phosphate based glasses and glass-ceramics play a crucial role in the development of tissue engineering. These materials have a high biocompatibility with biological analogues, excellent ability to undergo varying degrees of resorbability and due to their non-toxicity and relatively high bioactivity they are commonly used as bone and dental implants. A substantial research effort is devoted to improve synthetic calcium-phosphate materials physico-chemical properties, inter alia tune the degree of crystallinity which is mainly responsible for material solubility. One of the strategies is their doping with metal ions. The results found in the literature show that synthesized CaO-P2O5-Nb2O5 compounds exhibit a good biocompatibility, very low cytotoxicity in respect to calcium-phosphate doped with other metals and additionally can enhance human osteoblast function. Moreover, a really few information on the structure of these materials can be found in the literature. Therefore, the detailed structural investigation by means of spectroscopic studies, i.e. infrared absorption spectroscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy and X-ray absorption fine structure spectroscopy, was realized to shed light on the relationship between structural parameters and dopant contents, preparation technique or sample morphology and porosity. In this work, we show the results obtained for bioactive glass-ceramics with Ca/(P+Nb) molar ratio equal to 1.0 and with relative Nb contents reaching value up to 10 mol% of P ions, prepared by melt-quenching (MQ) and sol-gel (SG) methods.
Structural Reliability Assessment Of Corroded Tanker Ship Based On Experimentally Estimated Ultimate Strength
- Krzysztof Wołoszyk
- Yordan Garbatov
2019 Pełny tekst Polish Maritime Research
This work deals with the reliability assessment of a tanker ship hull structure subjected to a vertical bending moment and corrosion degradation. The progressive collapse and ultimate load carrying capacity are estimated based on experimentally tested scaled box-shaped-specimens. The translation of the strength estimate of the scaled specimen to the real tanker ship hull structure is performed based on the dimensional theory developing a step-wise linear stress-strain relationship. The load-carrying capacity is considered as a stochastic variable, and the uncertainties resulted from the scaled-specimen to the real-structure strength translation, and the subjected load of the real ship are also accounted for. A sensitivity analysis concerning the stochastic variables, included in the ultimate limit state function is performed. The partial safety factors, in the case of a scaled specimen and real structure, are also identified, and conclusions are derived.
Structural response of existing spatial truss roof construction based on Cosserat rod theory
- Mikołaj Miśkiewicz
2019 Pełny tekst CONTINUUM MECHANICS AND THERMODYNAMICS
Paper presents the application of the Cosserat rod theory and newly developed associated finite elements code as the tools that support in the expert-designing engineering practice. Mechanical principles of the 3D spatially curved rods, dynamics (statics) laws, principle of virtual work are discussed. Corresponding FEM approach with interpolation and accumulation techniques of state variables are shown that enable the formulation of the C0 Lagrangian rod elements with 6-degrees of freedom per node. Two test examples are shown proving the correctness and suitability of the proposed formulation. Next, the developed FEM code is applied to assess the structural response of the spatial truss roof of the “Olivia” Sports Arena Gdansk, Poland. The numerical results are compared with load test results. It is shown that the proposed FEM approach yields correct results.
Structure and evolution of the 4-helix bundle domain of Zuotin, a J-domain protein co-chaperone of Hsp70
- Om Shrestha
- Ruchika Sharma
- Bartlomiej Tomiczek
- Woonghee Lee
- Marco Tonelli
- Gabriel Cornilescu
- Milena Stolarska
- Łukasz Nierzwicki
- Jacek Czub
- John Markley
- Jaroslaw Marszalek
- Szymon Ciesielski
- Elizabeth Craig
2019 Pełny tekst PLOS ONE
The J-domain protein Zuotin is a multi-domain eukaryotic Hsp70 co-chaperone. Though it is primarily ribosome-associated, positioned at the exit of the 60S subunit tunnel where it promotes folding of nascent polypeptide chains, Zuotin also has off-ribosome functions. Domains of Zuotin needed for 60S association and interaction with Hsp70 are conserved in eukaryotes. However, whether the 4-helix bundle (4HB) domain is conserved remains an open question. We undertook evolutionary and structural approaches to clarify this issue. We found that the 4HB segment of human Zuotin also forms a bundle of 4 helices. The positive charge of Helix I, which in Saccharomyces cerevisiae is responsible for interaction with the 40S subunit, is particularly conserved. However, the C-termini of fungal and human 4HBs are not similar. In fungi the C-terminal segment forms a plug that folds back into the bundle; in S. cerevisiae it plays an important role in bundle stability and, off the ribosome, in transcriptional activation. In human, C-terminal helix IV of the 4HB is extended, protruding from the bundle. This extension serves as a linker to the regulatory SANT domains, which are present in animals, plants and protists, but not fungi. Further analysis of Zuotin sequences revealed that the plug likely arose as a result of genomic rearrangement upon SANT domain loss early in the fungal lineage. In the lineage leading to S. cerevisiae, the 4HB was subjected to positive selection with the plug becoming increasingly hydrophobic. Eventually, these hydrophobic plug residues were coopted for a novel regulatory function—activation of a recently emerged transcription factor, Pdr1. Our data suggests that Zuotin evolved off-ribosome functions twice—once involving SANT domains, then later in fungi, after SANT domain loss, by coopting the hydrophobic plug. Zuotin serves as an example of complex intertwining of molecular chaperone function and cell regulation.
Structure and optical parameters of Eu doped tellurium oxide thin films prepared by reactive magnetron sputtering method
- Marcin Łapiński
- Michalina Walas
- Anna Gapska
- Dorota Kulik
- Aneta Szmytke
- Piotr Twardowski
- Wojciech Sadowski
- Barbara Kościelska
2019 Pełny tekst THIN SOLID FILMS
In this work the structural properties and photoluminescence of tellurium dioxide thin films doped by europium were described. Thin films were deposited by magnetron sputtering method and simultaneously heated at 200 °C. Presence of Eu ions and their valence states was confirmed by X-ray photoemission spectroscopy measurements. The structure of the films as well as the influence of europium dopant on crystalline structure of the films was examined by X-ray diffraction method. Morphology of the samples was observed by atomic force microscope. Doping by europium didn't change structural parameters. Optical measurements showed photoluminescence from Eu2+ and Eu3+ ions. However, in the spectrum there is no line corresponding to 5D0 → 7F2 transition due to an electric-dipole transition, usually present in amorphous surrounding.
Structure and the space vector modulation for a medium-voltage power-electronic-transformer based on two seven-level cascade H-bridge inverters
- Arkadiusz Lewicki
- Marcin Morawiec
2019 Pełny tekst IET Electric Power Applications
This study presents the structure and the space vector pulse-width modulation (SVPWM) for power electronic transformer (PET) based on two seven-level cascade H-bridge (CHB) inverters. The DC links of CHB inverters are coupled with nine dual-active bridge (DAB) converters with medium-frequency transformers. The DC-link voltages are equalised with two methods – through the control of DAB voltages and through the modulation strategy applied to both CHB inverters. In the proposed SVPWM, the influence of vector sequences on predicted DC-link voltages is analysed, and the optimum vector sequence is selected to equalise them. Regardless of this, the proposed SVPWM strategy enables the proper generation of output voltage vector also in the case of DC-link voltage imbalance – the calculation of the space-vector area takes into consideration the inequality of the DC-link voltages and its influence on the lengths and positions of active vectors. To simplify the modulation algorithm, the multilevel CHB inverter is considered as a set of three-level inverters connected in series. Each of them is controlled using the same SVPWM algorithm. The proposed modulation method reuses the H-bridges with zero duty cycles determined in the initial stages of the output voltage generation process. This enables the optimal management of the DC-link voltage distribution. The experimental research was carried out on a 600 kW/3.3 kV PET. The results are presented in this study.