2018 - Repozytorium publikacji - Politechnika Gdańska

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Thermal degradation kinetics of poly(propylene succinate) prepared with the use of natural origin monomers
- Paulina Parcheta
- Iwona Koltsov
- Ewa Głowińska
- Janusz Datta
2018 Pełny tekst Polimery
Linear biobased polyester polyols were prepared with the use of succinic acid and 1,3-pro- panediol (both with natural origin). Tetraisopropyl orthotitanate (TPT) was used as a catalyst. In order to determine the effect of various synthesis temperature conditions on the thermal degradation kinet- ics, nine sequences of temperature conditions were used during two-step polycondensation reaction. Thermogravimetric analysis was conducted with the use of DSC-TG/QMS method (differential scanning calorimetry-coupled with thermogravimetry and quadrupole mass spectrometry). The results indicated high thermal stability of the obtained materials. They undergo a one-step thermal decomposition with the temperature of maximum rate of weight loss at ca. 405 °C. Moreover, the thermal degradation kinet- ics was determined with the use of Ozawa, Flynn and Wall as well as Kissinger methods. The highest thermal degradation activation energy was equal to 196.4 kJ/mol.
Thermal energy storage using stearic acid as PCM material
- Janusz Cieśliński
- Maciej Fabrykiewicz
2018 Pełny tekst Journal of Mechanical and Energy Engineering
This work presents an experimental study of thermal energy storage by use of PCM. The aim of the study was to establish the influence of different inlet temperature of heat transfer fluid (HTF) and different Reynolds number of HTF on intensity of charging process. The PCM used in this study was stearic acid and water was used as HTF. A copper helical coil mounted in cylindrical container served as a heat transfer surface.
Thermo-Chemical Decomposition Study of Polyurethane Elastomer Through Glycerolysis Route with Using Crude and Refined Glycerine as a Transesterification Agent
- Janusz Datta
- Patrycja Jutrzenka Trzebiatowska
- Diego Simón
- Juan F. Rodríguez
2018 Pełny tekst JOURNAL OF POLYMERS AND THE ENVIRONMENT
Due to the increasing amount of polyurethane waste, chemical recycling of these materials is a topic of growing interest for many researchers. The primary pur- pose of polyurethane feedstock recycling is to recover the starting polyol. In this study glycerolysis using glycerine from two sources and two purity grades is proposed as a method of chemical recycling. The main effort of this paper focuses on the employment of commercial glycerine of analytical grade and waste glycerine without purification derived from the biodiesel production, as a decomposing agent for polyurethane recycling. In this study, the influ- ence of polyurethane to glycerine mass ratio (PU/GL) and the type of decomposing agent on the chemical structure by FTIR, 1H NMR and GPC was examined. FTIR analy- sis of the glycerolysates showed absorption peaks similar to the virgin polyol. Those results are in compliance with GPC chromatograms, which showed for all samples, well- defined peak at ca. 13 min of retention time. The molec- ular weight of glycerolysates was ranging from 800 to 1300 g mol−1 depending on PU/GL mass ratio. The novel decomposition agent, namely waste glycerine derived from biodiesel production was successfully used in glycerolysis process.
Thermodynamic, Anticoagulant, and Antiproliferative Properties of Thrombin Binding Aptamer Containing Novel UNA Derivative
- Weronika Kotkowiak
- Jolanta Lisowiec-Wachnicka
- Jakub Grynda
- Ryszard Kierzek
- Jesper Wengel
- Anna Pasternak
2018 Pełny tekst Molecular Therapy-Nucleic Acids
Thrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA) is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular, antiparallel G-quadruplex structure with a chair-like conformation. In this paper, we report on our investigations on the influence of certain modified nucleotide residues on thermodynamic stability, folding topology, and biological properties of TBA variants. In particular, the effect of single incorporation of a novel 4-thiouracil derivative of unlocked nucleic acid (UNA), as well as single incorporation of 4-thiouridine and all four canonical UNAs, was evaluated. The studies presented herein have shown that 4-thiouridine in RNA and UNA series, as well as all four canonical UNAs, can efficiently modulate G-quadruplex thermodynamic and biological stability, and that the effect is strongly position dependent. Interestingly, TBA variants containing the modified nucleotide residues are characterized by unchanged folding topology. Thrombin time assay revealed that incorporation of certain UNA residues may improve G-quadruplex anticoagulant properties. Noteworthy, some TBA variants, characterized by decreased ability to inhibit thrombin activity, possess significant antiproliferative properties reducing the viability of the HeLa cell line even by 95% at 10 μM concentration.
Thermoplastic Elastomers Filled With GTR
- Krzysztof Formela
- Józef Haponiuk
- Shifeng Wang
- Xavier Colom
2018
In recent years, searching for new and cost-effective methods of recycling waste tires has been a subject of research in many laboratories worldwide. This is due to regulations in the law and environmental factors, which have both stimulated industry to re-use high quality rubber found in ground tire rubber (GTR). One of the most promising solutions in this area seems to be thermoplastic elastomers (TPEs) filled with GTR, which are economical and a pro-ecological alternative for commercially available TPEs. This chapter describes the recent advances in processing and characterization of thermoplastic elastomers filled with GTR. Special attention has been focused on the structure–properties relationships and compatibilization strategies of the studied TPEs. Moreover, the future trends in the development of TPEs filled with GTR are proposed and discussed.
Threats to Rural Landscape and Its Protection in Poland
- Anna Górka
2018 Pełny tekst Environments
The article describes the premises and conditions for the implementation of a pro-landscape spatial policy in rural areas in Poland. It presents the erosion of spatial order in a large part of the country’s territory. Firstly, the state of protection of the rural landscape and the legal aspects of shaping the space of rural areas are described. Secondly, the location is depicted, and the main physiognomic and environmental threats in the rural areas are discussed. It is then questioned whether the statutory regulations that have been introduced into the spatial planning system and adapt the Polish law to the requirements of the European Landscape Convention will stop the degradation of the landscape. Deep systemic changes are needed, as they will lead to the involvement of public policy in shaping the landscape and the introduction of tools and procedures for the management of visual landscape resources. They would constitute a convenient space for mediation in the relations between actors operating in space and an open knowledge laboratory of the environment, which would be useful in the participatory planning process. The presented arguments and conclusions result from the review and analysis of research results, which are mainly in the field of landscape protection and rural area management.
Three levels of fail-safe mode in MPI I/O NVRAM distributed cache
- Artur Malinowski
- Paweł Czarnul
2018 Pełny tekst Procedia Computer Science
The paper presents architecture and design of three versions for fail-safe data storage in a distributed cache using NVRAM in cluster nodes. In the first one, cache consistency is assured through additional buffering write requests. The second one is based on additional write log managers running on different nodes. The third one benefits from synchronization with a Parallel File System (PFS) for saving data into a new file which allows to keep file history at the cost of space. We have shown that the three level fail-safe mode incorporating these versions does introduce minimal overhead for a random walk microbenchmark application for a 1GB file and checkpoints created every 2000 iterations, computing powers of a graph with 10000 vertices and up to 20% overhead for parallel processing of images up to 1000 megapixels compared to the basic NVRAM cache without fail-safe modes. We also presented times for checkpoint creation and restoring for sizes up to 10GBs.
Three-dimensional geographically weighted inverse regression (3GWR) model for satellite derived bathymetry using Sentinel-2 observations
- Andrzej Chybicki
2018 Pełny tekst MARINE GEODESY
Current trends of development of satellite derived bathymetry (SDB) models rely on applying calibration techniques including analytical approaches, neuro-fuzzy systems, regression optimization and others. In most of the cases, the SDB models are calibrated and verified for test sites, that provide favourable conditions for the remote derivation of bathymetry such as high water clarity, homogenous bottom type, low amount of sediment in the water and other factors. In this paper, a novel 3-dimensional geographical weighted regression (3GWR) SDB technique is presented, it binds together methods already presented in other studies, the geographically weighted local regression (GWR) model, with depth dependent inverse optimization. The proposed SDB model was calibrated and verified on a relatively difficult test site of the South Baltic near-shore areas with the use of multispectral observations acquired by a recently launched Sentinel-2 satellite observation system. By conducted experiments, it was shown that the proposed SDB model is capable of obtaining satisfactory results of RMSE ranging from 0.88 to 1.23[m] depending on the observation and can derive bathymetry for depths up to 12m. It was also shown, that the proposed approach may be used operationally, for instance, in the continuous assessment of temporal bathymetry changes, for areas important in the context of ensuring local maritime safety.
Three-objective antenna optimization by means of kriging surrogates and domain segmentation
- Sławomir Kozieł
- Adrian Bekasiewicz
2018 Pełny tekst
In this paper, an optimization framework for multi-objective design of antenna structures is discussed which exploits data-driven surrogates, a multi-objective evolutionary algorithm, response correction techniques for design refinement, as well as generalized domain segmentation. The last mechanism is introduced to constrain the design space region subjected to sampling, which permits reduction of the number of training data samples required for surrogate model identification. The generalized segmentation technique works for any number of design objectives. Here, it is demonstrated using a three-objective case study of a UWB monopole optimized for best in-band reflection, minimum gain variability, and minimum size. The numerical results indicate that segmentation leads to reducing the cost of initial Pareto identification by around 21 percent as compared to the conventional surrogate-assisted approach.
Threshold Attendance under Soft-Crash Model: TAG Protocol and Markovian Analysis
- Jerzy Konorski
2018 Pełny tekst
A realistic and systematic network evaluation should subsume an availability model and a failure model. We combine a "hard availability" model we call threshold attendance, whereby a certain minimum number of network elements must be present at any time, with a soft-crash failure model, whereby after experiencing a failure, a network element is still able to function correctly for a while in an emergency mode at a risk of a major crash. A Threshold Attendance Guarantee (TAG) protocol, earlier studied from a security viewpoint, is deployed to ensure threshold attendance while controlling the duration of the emergency mode. We study the network under TAG using an "isolated" node-type Markovian analysis, offering insights into the tradeoffs between some relevant availability and reliability characteristics, and showing a simple model-free way to account for a positive correlation between the network elements' behavior that can reflect mass disasters.
Tight bounds on the complexity of semi-equitable coloring of cubic and subcubic graphs
- Hanna Furmańczyk
- Marek Kubale
2018 Pełny tekst DISCRETE APPLIED MATHEMATICS
We consider the complexity of semi-equitable k-coloring, k>3, of the vertices of a cubic or subcubic graph G. In particular, we show that, given a n-vertex subcubic graph G, it is NP-complete to obtain a semi-equitable k-coloring of G whose non-equitable color class is of size s if s>n/3, and it is polynomially solvable if s, n/3.
Timber frame houses resistant to dynamic loads - seismic analysis
- Marcin Szczepański
- Wojciech Migda
2018 Pełny tekst MATEC Web of Conferences
The aim of the article is to present results of seismic analysis results of two real-sized timber frame buildings subjected to seismic excitations. The first model was insulated with mineral wool, the second one with polyurethane foam. Technology and specifications involved in both models construction is based on the previously conducted experimental research on timber frame houses, including wall panels tests, wall numerical models and study on material properties and precisely reflect results of the those research. During the seismic analysis reference node located in buildings were selected. In selected node displacement values were measured and compared between two analyzed models. The results of the numerical analysis presented in the article indicate that the application of polyurethane foam for a skeleton filling of the timber-frame building leads to the increase in stiffness as well as damping of the whole structure, which results in a considerable increase in the seismic resistance of the structure.
TIME SERIES DATA FOR 3D FLOOD MAPPING
- Beata Wieczorek
- Anna Sobieraj-Żłobińska
- Tomasz Sidorowicz
2018
Thanks to the ability to collect information about large areas and with high frequency in time areas threatened by floods can be closely monitored. The effects of flooding are socio-economic losses. In order to reduce those losses, actions related to the determination of building zones are taken. Moreover, the conditions to be met by facilities approved for implementation in such areas are determined. Therefore, satellite data from the Earth observation program play a key role in assessing water conditions that are variable in space and in time. The article specifies the probability of flooding the area in the vicinity of the Łyna River valley in the Sępopol commune. The analysis has been carried out for areas where floods have occurred. The spatial data from airborne laser scanning and satellite radar interferometry was examined in the context of its usefulness in the determination of the maximum possible extent of flooding. In order to transform data into useful information, it was necessary to integrate both the spatial and temporal dimension of the SAR time series. Finally, digital terrain model with high resolution was created.
Time-domain measurement methods for R, L and C sensors based on aversatile direct sensor-to-microcontroller interface circuit
- Zbigniew Czaja
2018 Pełny tekst SENSORS AND ACTUATORS A-PHYSICAL
tIn the paper new time-domain measurement methods for determining values of resistive (R), inductive(L) and capacitive (C) sensors based on a versatile direct sensor-to-microcontroller interface for microcon-trollers with internal analog-to-digital converters (ADCs) and analog comparators (ACs) are presented.The interface circuit consists of a reference resistor Rrworking as a voltage divider, a given R, L or C sensorand a microcontroller (its peripherals: an ADC, an AC, a timer, I/O pins buffered by an inverter). A pro-totype of the proposed complete solution of a compact smart sensor based on an 8-bit microcontrollerhas been developed and tested. The maximum possible relative inaccuracy of an indirectly measurableresistance, inductance and capacitance were analysed. Also, experimental researches were made. Thefollowing relative errors of the sensor value determination were achieved: for the R sensor less than 3%,as well as very good results for the L sensor (less than 0.3%) and for the C sensor (less than 0.2%).
Time-of-flight electron scattering from molecular hydrogen: Benchmark cross sections for excitation of the X1Σ+g→b3Σ+u transition
- Mateusz Zawadzki
- Robert Wright
- Grant Dolmat
- Merl Martin
- Leigh Hargreaves
- Dmitry Fursa
- Mark Zammit
- Liam Scarlett
- Jonathan Tapley
- Jeremy Savage
- Igor Bray
- Murtadha Khakoo
2018 Pełny tekst PHYSICAL REVIEW A
The electron impact X1Σ+g to b3Σ+u transition in molecular hydrogen is one of the most important dissociation pathways to forming atomic hydrogen atoms, and is of great importance in modeling astrophysical and industrial plasmas where molecular hydrogen is a substantial constituent. Recently it has been found that the convergent close-coupling (CCC) cross sections of Zammit et al. [Phys. Rev. A 95, 022708 (2017)] are up to a factor of two smaller than the currently recommended data. We have performed measurements of differential cross sections as ratios of the excitation to elastic scattering using a transmission-free time-of-flight electron spectrometer, and find excellent agreement with the CCC calculations. Since there is already excellent agreement for the absolute elastic differential cross sections, we establish new recommended differential and integrated cross sections with theory and experiment being essentially in complete agreement- unprecedented for differential electron impact excitation of any molecular transition to date.
TiO 2 Co x O y composite nanotube arrays via one step electrochemical anodization for visible light–induced photocatalytic reaction
- Marek Kobylański
- Paweł Mazierski
- Anna Malankowska
- Magda Kozak
- Magdalena Diak
- Michał Jerzy Winiarski
- Tomasz Klimczuk
- Wojciech Lisowski
- Grzegorz Nowaczyk
- Adriana Zaleska-Medynska
2018 Surfaces and Interfaces
TiO2CoxOy (x = 1, y = 1 or x = 3, y = 4) composite photocatalysts have been synthesized via one step anodic anodization of TiCo alloys. The effects of the cobalt content in the alloy (5, 10 and 15 wt%), water content (2, 5 and 10%) in the electrolyte solution, and applied voltage (30, 40 and 50 V) during the anodization process on the morphology and surface properties. Additionally, the dependence of cobalt content in the nanotubes (0.06–0.09 at. %) on photocatalytic properties of the obtained materials have been investigated systematically. It was shown that the amount of cobalt in the TiCo alloy affected morphology as well as photocatalytic activity of obtained composites. Moreover, the diameter and wall thickness of the TiO2CoxOy composites could be precisely controlled by applied voltage value, water content in electrolyte and cobalt content in the working electrode. The TiO2CoxOy composite nanotubes exhibit enhanced photocatalytic degradation rate of 0.444 µmol·dm−3·min−1 for phenol under visible light compared with unmodified TiO2 NTs 0.140 µmol·dm−3·min−1. XPS analysis revealed that the content of Co species in the surface layer of nanotubes is similar (from 0.06 to 0.09 at.%), independently on cobalt amount in used substrate, due to leakage of Co ions to the electrolyte during anodic oxidation. Phenol degradation in the presence of scavengers shown that the superoxide radical species O2•− were found to be main active species responsible for high efficiency of degradation.
TIRE/ROAD NOISE AND TIRE ROLLING RESISTANCE ON PROTOTYPE PERS SURFACE
- Stanisław Taryma
- Ryszard Woźniak
- Jerzy Ejsmont
- Piotr Mioduszewski
- Grzegorz Ronowski
2018 Pełny tekst IOP Conference Series: Materials Science and Engineering
Poroelastic road surfaces are characterized by low noise of tires running on them.Road pavements of this type are promising solution to problems related to traffic noise in cities and on rural roads. Some technical problems still have to be solved, in particular regarding durability and skid resistance on wet surface. Ongoing and planned works are to contribute to create a quiet, durable and safe road surface, which will become an alternative to acoustic screens and vehicle speed reduction as an efficient noise reduction measure. The paper presents the results of laboratory and road tests of tire/road noise and rolling resistance on the prototype poroelastic surface (PERS) compared to the surfaces selected as a reference.
Tire/Road Noise On Poroelastic Road Surfaces - Results Of Laboratory Measurements
- Jerzy Ejsmont
- Beata Świeczko-Żurek
- Wojciech Owczarzak
- Sławomir Sommer
- Grzegorz Ronowski
2018 Pełny tekst
Tire/road noise is the most important part of traffic noise for medium and high speed driving both in the case of passenger cars and trucks. The potential to make modification of tires that significantly reduce tire/road noise in nearly over, at least for conventional tires so the only promising action is to improve road pavements. One of the innovative solutions is poroelastic road pavement (PERS) that reduces airflow related noise mechanisms due to its porosity and impact related mechanisms owing to its elasticity. Although the existing PERS test sections are still struggling with certain problems most notably non satisfactory durability and somewhat low friction, the experiments show that substantial progress is possible and the acoustic performance of PERS is very good making it the most quiet road pavements so far. The paper presents results of laboratory tests of PERS performed at the Technical University of Gdańsk both for car and truck tires.
Titania nanotubes modified by a pyrolyzed metal-organic framework with zero valent iron centers as a photoanode with enhanced photoelectrochemical, photocatalytical activity and high capacitance
- Mariusz Szkoda
- Konrad Trzciński
- Andrzej Nowak
- Emerson Coy
- Leszek Wicikowski
- Marcin Stanisław Łapiński
- Katarzyna Siuzdak
- Anna Lisowska-Oleksiak
2018 ELECTROCHIMICA ACTA
The paper discusses the synthesis, photoelectrochemical and electrochemical behaviour of titania nanotube arrays modified by a pyrolyzed metal-organic framework (MOF). A poly(3,4–ethylenedioxyphene) (PEDOT) matrix with an embedded inorganic network of iron hexacyanoferrate (BP) covering TiO2 nanotubes (TNT) is used as a MOF for the further sintering procedure, resulting in a novel, thin film of carbonaceous wrap supported Fe catalytic centers: TNT@C:Fe. UV–Vis and Raman spectroscopies were utilized to characterize the absorbance capability and the crystalline phase of titania, respectively. XPS was used for identification of the valence stage of iron Fe(0), Fe(II), Fe(III) in the shell part of the novel composite TNT@C:Fe. The electrochemical performance of the modified nanotubular TiO2 electrodes has been monitored by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge cycles in an aqueous electrolyte. TNT@C:Fe exhibited the capacitance of 9.1 mF cm−2 even after 5000 cycles, being much higher than pure titania (2.1 mF cm−2). The photocurrent density reached 304 μA cm−2 for TNT@C:Fe, whereas only 32 μAcm−2 was registered for pure titania nanotubes under simulated solar light illumination at a potential of +0.5 V. An improved decolorization rate of methylene blue in water confirms enhanced photoactivity of TNT@C:Fe in comparison with pristine titania nanotubes.
Tłumienie drgań w elektromechanicznych strukturach periodycznych
- Wiktor Waszkowiak
2018 Pełny tekst
Praca dotyczy wykorzystania elektromechanicznych struktur periodycznych do tłumienia drgań jedno- i dwuwymiarowych elementów konstrukcyjnych. Głównym celem pracy było opracowanie modeli numerycznych jedno- i dwuwymiarowych struktur periodycznych, zarówno pasywnych jak i aktywnych oraz jednowymiarowych wykorzystujących elementy piezoelektryczne. Cel ten osiągnięto dzięki przeprowadzeniu symulacji komputerowych w oparciu o opracowane modele numeryczne na bazie metody spektralnych elementów skończonych w dziedzinie czasu i częstotliwości. Uzyskane wyniki symulacji zostały zweryfikowane eksperymentalnie dzięki wykorzystaniu laserowej wibrometrii skaningowej. W odniesieniu do jedno- i dwuwymiarowych pasywnych struktur periodycznych analizie poddano drgania własne: wzdłużne, giętne i skrętne belek izotropowych oraz tarcz i płyt. Zbadano również efektywność tłumienia fal sprężystych w jedno- i dwuwymiarowych strukturach periodycznych. W odniesieniu do jednowymiarowych struktur aktywnych, wykorzystujących elementy piezoelektryczne pracujące w układzie rezonansowym RLC, analizie poddano drgania wymuszone wzdłużne i giętne oraz badano propagacje fal wzdłużnych i giętnych. Sprawdzono również wpływ parametrów układu rezonansowego RLC na drgania i fale propagowane w strukturach. Uzyskane wyniki badań pozwoliły na określenie ogólnych zależności występowania zjawisk wynikających z periodyczności struktury, manifestujących się obecnością pasm zabronionych, od parametrów struktury periodycznej, czy to pasywnej czy aktywnej, i jej komórki elementarnej. Pokazano, że struktury periodyczne z aktywnymi elementami piezoelektrycznymi włączonymi w obwód rezonansowy RLC mogą być z powodzeniem wykorzystywane do tłumienia drgań w sposób kontrolowany.