Repozytorium publikacji - Politechnika Gdańska

Biopolyols obtained via microwave-assisted liquefaction of lignin: structure, rheological, physical and thermal properties

• Kamila Gosz
• Paulina Kosmela
• Aleksander Hejna
• Grzegorz Gajowiec
• Łukasz Piszczyk

2018 Pełny tekst WOOD SCIENCE AND TECHNOLOGY

The present study examined the application of polyols obtained via microwave-assisted liquefaction of lignin in the production of rigid polyurethane foam. Lignin was liquefed in crude glycerol and 1,4-butanediol at diferent temperatures (130–170 °C), without a catalyst and using various biomass concentrations (15 and 30 wt%). The physicochemical properties, process yield, and FTIR-based identifcation of the obtained polyols were investigated. Under optimal conditions, i.e., a 5-min microwave heating time and a reaction temperature of 150 °C, a polyol characterized by a suitable hydroxyl number of 670 mg KOH/g was obtained with a 93% process yield. Liquefed biopolyol was directly used for the production of rigid polyurethane foams with the addition of polymeric diphenylmethane diisocyanate at the [NCO/OH] ratio of 2:1. Mechanical properties of the obtained foams gradually improved with increasing content of biopolyol. The 5% weight loss temperature (T5) for bio-based foams was higher, respectively 6 and 13 °C compared to the petrochemical foam. Replacement of petrochemical polyether with biopolyols showed the ability to obtain rigid polyurethane foams from lignin and crude glycerol.

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BIOVAC® WASTEWATER TREATMENT PLANTS IN THE MOUNTAIN NATIONAL PARKS.

• Barbara Wilk
• Małgorzata Cimochowicz-Ribicka

2018 Pełny tekst Czasopismo Techniczne

This paper presents characteristics of the Biovac® wastewater treatment plants operating in the mountain areas of the Polish national parks (NP): Tatrzanski NP and Babiogórski NP as well as in the West Spitsbergen NP. On the basis of the laboratory tests performed on raw sewage and the final effluent the efficiency of the wastewater treatment plants was evaluated. It was found that high COD values and rather high COD / BOD5 ratios were observed in the raw sewage during an off-peak tourist season. The research has also shown that the Biovac® treatment plants (SBR technology) showed a high level of removal of pollutants from sewage discharged from mountain hostels.

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Birch sap concentrate as a potential modern food product

• Bilek Maciej
• Jarosław Wawer
• Wojciech Szwerc
• Katarzyna Słowik
• Stanisław Sosnkowski

2018 Econtechmod. An International Quarterly Journal on Economics of Technology and Modelling Processes

This paper presents birch sap concentrate obtained by the reverse osmosis method. It is characterized by sweet taste, high content of minerals and no risk to consumers in terms of content of heavy metals standardized in the European Union food legislation. This beverage has all the features of a modern food product, i.e. it has an attractive taste, is obtained using new technology, meets the clean label requirements and can be classified as a superfoods product.

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Birds' feathers – Suitable samples for determination of environmental pollutants

• Małgorzata Rutkowska
• Justyna Płotka-Wasylka
• Martyna Lubinska-Szczygeł
• Anna Różańska
• Justyna Możejko-Ciesielska
• Jacek Namieśnik

2018 Pełny tekst TRAC-TRENDS IN ANALYTICAL CHEMISTRY

The intensive development of industry and human population results in large amounts of different xenobiotic emitted into individual ecosystem components. As a consequence, monitoring of the level of pollution of particular elements of the environment by exotoxins has become a common interest. The determination of environmental changes by different types of biological indicators is called bioindication, which is used as one of the basic methods in the monitoring of environmental pollution. The following review paper contains comprehensive information about the use of bird feathers to assess the environmental contamination level. Types of contaminants (trace metals, microplastics, persistent organic pollutants) and analytical methods used for their determination are described in detail. In addition, the types of feathers used and the techniques for preparing them as samples for analysis are summarized.

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Bis-phosphonated carbon nanotubes: one pot synthesis and their application as efficient adsorbent of mercury

• Kamila Sadowska
• Diana Sobota
• Bartłomiej Cieślik
• Marta Prześniak-Welenc
• Marcin Stanisław Łapiński
• Jan Biernat

2018 FULLERENES NANOTUBES AND CARBON NANOSTRUCTURES

Effective, one-pot method of CNTs phosphonylation is presented. Cheap and readily available reagents are used, so the process can be easily transferred to large-scale production. The product was analyzed using spectroscopic methods (FTIR, UV-vis, XPS). Thermal properties of the bis-phosphonated nanotubes are reported for the first time. Newly obtained material was tested as an adsorbent for mercury removal from water. The sorption capacity for newly developed adsorbent was as high as 223.7 mg/g. The adsorption kinetics were studied within framework of Lagergren model, and Langmuir and Freundlich isotherms have been described. The effect of pH on the adsorption process has been evaluated and the optimal environmental conditions were determined to be neutral. The presence of bivalent ions Cd2+, Ni2+ in the solution did not affect adsorption efficiency of novel materials.

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Block Conjugate Gradient Method with Multilevel Preconditioning and GPU Acceleration for FEM Problems in Electromagnetics

• Adam Dziekoński
• Michał Mrozowski

2018 IEEE Antennas and Wireless Propagation Letters

In this paper a GPU-accelerated block conjugate gradient solver with multilevel preconditioning is presented for solving large system of sparse equations with multiple right hand-sides (RHSs) which arise in the finite-element analysis of electromagnetic problems. We demonstrate that blocking reduces the time to solution significantly and allows for better utilization of the computing power of GPUs, especially when the system matrix is complex-valued. We show that, for a complex-valued sparse matrix with over 1.2 million unknowns and sixteen righthand-sides, the block version of the preconditioned conjugategradient method using a single NVIDIA Tesla P100 accelerator is almost three times faster than a nonblocked version. Numerical tests have also shown that a CPU-only nonblocked complex implementation is unlikely to benefit much from blocking. Compared to an optimized CPU-only solver using an Intel Xeon E5-2680 v3 with twelve cores, the nonblocked GPU-accelerated version was 4.5 times faster, while the blocked version was 12.4 times faster.

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Blood concentrations of a new psychoactive substance 4-chloromethcathinone (4-CMC) determined in 15 forensic cases

• Ewa Tomczak
• Mateusz Kacper Woźniak
• Marzena Kata
• Marek Wiergowski
• Beata Szpiech
• Marek Biziuk

2018 Pełny tekst Forensic Toxicology

Purpose: The 4-chloromethcathinone (4-CMC) is a synthetic derivative of cathinone and belongs to new psychoactive substances. Neither data on the effects of 4-CMC on the human body, nor on nontoxic, toxic and lethal concentrations in biological materials have been published in the literature. This paper describes the results of an analysis of the blood concentrations of 4-CMC determined in 15 forensic cases related to nonfatal intoxication including driving under the influence, and fatalities including overdoses, suicide and traffic accidents. Methods A new method for the quantification of 4-CMC using gas chromatography–mass spectrometry (GC–MS) was developed. The symptoms of 4-CMC use were also studied based on an analysis of the documents prepared during the collection of samples or at autopsies. Results The limits of detection and quantification of the method for blood samples were 0.3 and 1 ng/mL, respectively. The calibration curve was linear in the studied concentration range (1–500 ng/mL) with the correlation coefficient at 0.9979. The extraction recoveries varied in the range of 94.3–98.8%. The accuracy and precision were acceptable. The determined concentrations in nonfatal cases ranged from 1.3 to 75.3 ng/mL, and in fatalities from 56.2 to 1870 ng/mL. Conclusions Our study can assist in the recognition of the possible effects caused by 4-CMC and can be helpful during the preparation of forensic toxicological opinions for courts of law. The validation parameters indicate the sensitivity and accuracy of the method. This is the first work presenting a validated method for the determination of 4-CMC in blood samples by GC–MS.

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Blood Pressure Estimation Based on Blood Flow, ECG and Respiratory Signals Using Recurrent Neural Networks

• Artur Poliński
• Krzysztof Czuszyński
• Tomasz Kocejko

2018

The estimation of systolic and diastolic blood pressure using artificial neural network is considered in the paper. The blood pressure values are estimated using pulse arrival time, and additionally RR intervals of ECG signal together with respiration signal. A single layer recurrent neural network with hyperbolic tangent activation function was used. The average blood pressure estimation error for the data obtained from 21 subjects from MIMIC database was equal to 2.490 mmHg with standard deviation equal to 1.063 mmHg for systolic blood pressure, and was equal to 1.330 mmHg with standard deviation equal to 0.627 mmHg for diastolic blood pressure using vanilla recurrent neural networks. Similar results were obtained for long short term memory cells. The simulation shows that taking into account pulse arrival time together with RR intervals and respiration signal gave better results than pulse arrival time alone

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Błedy w realizacji dachu stromego pokrytego dachówka ceramiczną

• Maciej Niedostatkiewicz

2018 Pokrycia Dachowe i Akcesoria

Na przykładzie zrealizowanego budynku pokazano wpływ błedów i niedociagnięc popełnionych podczas realizacji dachu pokrytego dachówka ceramiczna które doprowadziły do powstania istotnych ograniczeń w użytkowaniu obiektu

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Bonding in Phosphanylphosphinidene Complexes of Transition Metals and their Correlation with Structures, 31 P NMR Spectra, and Reactivities

• Mateusz Zauliczny
• Anna Ordyszewska
• Jerzy Pikies
• Rafał Grubba

2018 EUROPEAN JOURNAL OF INORGANIC CHEMISTRY

Theoretical studies of the bonding interactions and most important properties are carried out for isolable phosphanylphosphinidene complexes of transition metals. Three main types of phosphanylphosphinidene complexes are distinguished, based on the way in which the phosphanylphosphinidene ligand bonds to the metal center: (i) side-on complexes of platinum, where the R2Pβ–Pα ligand mimics structural features of free singlet phosphanylphosphinidenes with short, polarized, double P–P bonds and two lone electron pairs on the terminal P atom. In this case, interactions between the platinum center and the phosphanylphosphinidene ligand are determined by π(PP)→s(Pt) donation and d(Pt)→π*(PP) back-dona-tion; (ii) terminal and bridging complexes of zirconium, where the R2P–P ligand is bonded to the metal center only by the terminal P atom. The metal–ligand interactions are a result of the singly occupied p orbitals of a terminal P atom overlapping with the singly occupied d orbitals of the Zr atom, which leads to multiple bonding; (iii) side-on complexes of early transition metals, where the R2Pβ–Pα group is bonded to the metal through an R2Pβ–M single bond and a Pα=M double bond. The observed shortening of the P–P bond in these complexes is explained by a negative hyperconjugation, as a result of the interaction of the π(PαM) orbital with the σ*(PβC) orbitals.

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Borders of Digital Art in the Context of the Information Society

• Karolina Życzkowska
• Jan Buczkowski

2018

The article shows the relationship between the development of information technologies, the characteristics of the information society and digital art. The broad possibilities of the digital world related to recording, storing and processing data (cyber text, big data, smart services) and the creation of virtual worlds are pointed out. The influence of the development of information technologies on the character of the works of art (their variability and availability) is also considered. On the basis of representative examples, three areas of border-crossing in the manner of presenting and experiencing a digital art work are distinguished: entering the public space, virtual world and the recipient's private area. The possibilities of integrating the digital message within the architectural structure in the public space (media architecture using display technology and temporary projections) is indicated. The possibilities of digital art in the virtual world is also taken into consideration (generative art, Net Art, virtual museums). Moreover, the issue of digital art in the context of crossing the border of human privacy by means of information technology (monitoring, surveillance) is considered, stressing also the social aspect of interactive art. The article shows the almost unlimited possibilities in the field of digital art, which are determined only by the imagination of the artist.

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"Born Poland, Gone Global". The case of successful Polish ICT company - Aiton Caldwell

• Ewa Lechman

2018

This work examines the pathway to global markets of Polish ICT company Aiton Caldwell

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Borrowing Images of Empire. The contribution of research on the artistic influence of the Holy Roman Empire on Polish Romanesque architecture in the eleventh and twelfth centuries

• Piotr Samól

2018 Pełny tekst Studia z Dziejów Średniowiecza

Although knowledge concerning Romanesque architecture in Poland has developed over many years, most cathedrals and ducal or royal seats have not been comprehensively examined. Moreover, a substantial number of contemporary scholarly works have erased the thin line between material evidence and its interpretation. As a consequence, the architectural remains of Polish Romanesque edifices are often considered the basis for wider comparative research. Meanwhile, fragmentarily preserved structures of Romanesque buildings have allowed scholars to conduct research on their origins and models, but they have rarely provided enough information for spatial reconstructions of them. This means that one might investigate the process of transposing patterns from the Holy Roman Empire to Poland instead of the influence of Polish masons’ lodges on each other. Therefore, this paper has two aims. The first is to look at how imperial patterns affected the main stone structures (cathedrals and collegiate churches) in Poland before Germanic urbanisation in the thirteenth century. The another is to analyse, how the changes in knowledge of Imperial archetypes might influence the interpretation of their Polish copies.

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Bridges to Independence / Mosty ku niepodległości

• Krzysztof Wróblewski

2018

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Brief Announcement: Energy Constrained Depth First Search

• Das Shantanu
• Dariusz Dereniowski
• Przemysław Uznański

2018

Depth first search is a natural algorithmic technique for constructing a closed route that visits all vertices of a graph. The length of such route equals, in an edge-weighted tree, twice the total weight of all edges of the tree and this is asymptotically optimal over all exploration strategies. This paper considers a variant of such search strategies where the length of each route is bounded by a positive integer B (e.g. due to limited energy resources of the searcher). The objective is to cover all the edges of a tree T using the minimum number of routes, each starting and ending at the root and each being of length at most B. To this end, we analyze the following natural greedy tree traversal process that is based on decomposing a depth first search traversal into a sequence of limited length routes. Given any arbitrary depth first search traversal R of the tree T, we cover R with routes R(1),...,R(l), each of length at most B such that: R(i) starts at the root, reaches directly the farthest point of R visited by R(i-1), then R(i) continues along the path R as far as possible, and finally R(i) returns to the root. We call the above algorithm piecemeal-DFS and we prove that it achieves the asymptotically minimal number of routes l, regardless of the choice of R. Our analysis also shows that the total length of the traversal (and thus the traversal time) of piecemeal-DFS is asymptotically minimum over all energy-constrained exploration strategies. The fact that R can be chosen arbitrarily means that the exploration strategy can be constructed in an online fashion when the input tree T is not known in advance. Each route R(i) can be constructed without any knowledge of the yet unvisited part of T. Surprisingly, our results show that depth first search is efficient for energy constrained exploration of trees, even though it is known that the same does not hold for energy constrained exploration of arbitrary graphs.

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Broadband Compact Single-Layer Magic-T Junction with Separation of DC Signals between All Ports

• Wojciech Marynowski

2018 Pełny tekst RADIOENGINEERING

A novel structure for a four-port microstrip magic-T junction is presented. The device is composed of microstrip and slotline circuits etched onto two sides of a dielectric substrate. The device is extremely compact and occupies an area more than three times smaller than similar structures recently reported in the literature. The novelty of the device lies in the use of microstrip/slotline transitions for both input ports: summation (in-phase) port and difference (out-of-phase) port. This ensures electrical separation for DC signals between all four ports, a wide operation band and a very small size for the device. The fabricated prototype operates in a 95% fractional bandwidth with return losses better than 10 dB and isolation between input ports better than 35 dB. The insertion losses for the excitation at the summation port are about 0.8 dB and for the excitation at the difference port are about 1.4 dB. In the operation band of the device, the maximum amplitude imbalance is equal to ±0.3 dB, whereas the maximum phase imbalance is equal to ±4deg. .

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Buckling Analysis of a Micro Composite Plate with Nano Coating Based on the Modified Couple Stress Theory

• Mohammad Malikan

2018 Pełny tekst Journal of Applied and Computational Mechanics

The present study investigates the buckling of a thick sandwich plate under the biaxial non-uniform compression using the modified couple stress theory with various boundary conditions. For this purpose, the top and bottom faces are orthotropic graphene sheets and for the central core the isotropic soft materials are investigated. The simplified first order shear deformation theory (S-FSDT) is employed and the governing differential equations are obtained using the Hamilton’s principle by considering the Von-Karman’s nonlinear strains. An analytical approach is applied to obtain exact results with different boundary conditions. Due to the fact that there is no research on the stability of micro/nano sandwich plates based on S-FSDT including the couple stress effect, the obtained results are compared with the FSDT studies which use the Eringen nonlocal elasticity.

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Buckling analysis of piezo-magnetoelectric nanoplates in hygrothermal environment based on a novel one variable plate theory combining with higher-order nonlocal strain gradient theory

• Mohammad Malikan
• Van Bac Nguyen
• Francesco Tornabene

2018 Pełny tekst PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES

In the present investigation, a new first-order shear deformation theory (OVFSDT) on the basis of the in-plane stability of the piezo-magnetoelectric composite nanoplate (PMEN) has been developed, and its precision has been evaluated. The OVFSDT has many advantages compared to the conventional first-order shear deformation theory (FSDT) such as needless of shear correction factors, containing less number of unknowns than the existing FSDT and strong similarities with the classical plate theory (CPT). The composite nanoplate consisted of BaTiO3-CoFe2O4, a kind of material by which coupling between piezoelectric and piezomagnetic in nanosize was established. The plate is surrounded by a motionless and stationary matrix that is embedded in a hygrothermal surround in order to keep it more stable, and to take into consideration the influences of the moisture and temperature on the plate's mechanical behavior. The governing equilibrium equations for the smart composite plate have been formulated using the higher-order nonlocal strain gradient theory within which both stress nonlocality and second strain gradient size-dependent terms are taken into account by using three independent length scale parameters. The extracted equations are solved by utilizing the analytical approaches by which numerical results are obtained with various boundary conditions. In order to evaluate the proposed theory and methods of solution, the outcomes in terms of critical buckling loads are compared with those from several available well-known references. Finally, after determining the accuracy of the results of the new plate theory, several parameters are investigated to show the influences of material properties of the ceramic composite nanoplate on the critical buckling loads.

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Buckling of simplified models of silo with corrugated walls and vertical stiffeners

• Piotr Iwicki
• Karol Rejowski
• Andrzej Tejchman-Konarzewski

2018

The paper deals with buckling of cylindrical silos composed of corrugated sheets and vertical stiffeners (columns). Comprehensive finite element analyses were carried out for a perfect silo by means of a linear buckling approach. Corrugated walls were simulated as an equivalent orthotropic shell and vertical thin-walled columns as beam elements. Calculations for perfect silos with different numbers of columns made it possible to establish three different ranges of the silo buckling performance. Based on results of three dimensional calculations, an original simplified segment silo wall model was proposed for calculations of silo global buckling for sparsely distributed columns. The calculated buckling loads were compared with an allowable one given by EN 1993-4-1. In addition geometrically non-linear analyses for both imperfect and perfect silos were carried out.

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Budowa zewnętrznych sieci ciśnieniowych i bezciśnieniowych z materiałów plastycznych

• Ziemowit Suligowski

2018 Wiadomości Projektanta Budownictwa

Specyfika konstrukcji z tworzyw. Warunki techniczne budowy. Braki w formalnych regulacjach. Specyfika nowej (marzec 2018) normy krajowej

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