2020 - Repozytorium publikacji - Politechnika Gdańska

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Drill holes decrease cancellous bone strength: A comparative study of 33 paired osteoporotic human and 9 paired artificial bone samples
- Marcin Ceynowa
- Krzysztof Żerdzicki
- Paweł Kłosowski
- Rafał Pankowski
- Marek Rocławski
- Tomasz Mazurek
2020 Pełny tekst PLOS ONE
This study was designed to compare compressive strength of cancellous bone retrieved from the femoral head in a specimen with and without guide wire hole, with comparison to synthetic bone samples. Femoral heads retrieved from 33 patients who sustained femoral neck fractures and underwent hip arthroplasty were cut into cuboids leaving two matching samples from the same femoral head. Similar samples were prepared from synthetic femurs. One of the matching samples was chosen at random and was drilled with a guide wire for cancellous screws. The uniaxial compression tests of bone blocks were carried out using the Zwick-Roell Z020 strength testing machine. The mean loss of sample cross section area due to drilling was 24%. The force at failure in drilled specimens was significantly smaller by 18% in human (median: 26%) and by 25% in synthetic bone (median 27%). The strength of human specimens was almost 2 times greater, and their stiffness nearly 4 times greater than in synthetic samples. The study shows that the weakening of the bone after drilling is roughly proportional to the loss of sample cross section area. The percentage decrease in strength was similar in human and artificial bone, but human samples were stronger and stiffer. The comparison shows that forces measured in biomechanical studies on artificial bone cannot be directly attributed to humans, but the relative differences in mechanical properties of synthetic samples after some damage may be accurate and resemble that of human bones.
Droga S7 Koszwały – Kazimierzowo – geotechniczne aspekty inwestycji.
- Grzegorz Horodecki
2020
W artykule przedstawiono ogólne informacje dotyczące geotechnicznych aspektów projektu i realizacji drogi S7 na odcinku Koszwały – Kazimierzowo, ze szczególnym uwzględnieniem rozwiązań z zastosowaniem technologii zamkniętego materaca odciążającego z kruszywa lekkiego – keramzytu geotechnicznego. Przedstawiono metody wzmocnienia podłoża przyjęte na etapie projektu oraz realizacji wraz z monitoringiem geotechnicznym.
Druk 3D części z tworzyw sztucznych na skalę przemysłową w technologii SLS
- Dawid Zieliński
2020 Pełny tekst Tworzywa Sztuczne w Przemyśle
Firma EOS, wiodący i światowy dostawca technologii przemysłowego wykorzystania druku 3D dla materiałów metalicznych i polimerowych, zaprezentowała na targach formnext 2017 nowy system EOS P500, przeznaczony do addytywnego wytwarzania modeli. Drukarka 3D adresowana jest dla przedsiębiorstw chcących wytwarzać na skalę przemysłową części i elementy z tworzyw sztucznych o wysokiej jakości.
Druk 3D części z tworzyw sztucznych na skalę przemysłową w technologii SLS
- Dawid Zieliński
2020 Pełny tekst Materiały & Maszyny Technologiczne
Firma EOS, wiodący i światowy dostawca technologii przemysłowego wykorzystania druku 3D dla materiałów metalicznych i polimerowych, zaprezentowała na targach formnext 2017 nowy system EOS P500, przeznaczony do addytywnego wytwarzania modeli. Drukarka 3D adresowana jest dla przedsiębiorstw chcących wytwarzać na skalę przemysłową części i elementy z tworzyw sztucznych o wysokiej jakości.
Dynamic analysis of temporary steel grandstand subjected to human-induced excitations due to jumping
- Natalia Lasowicz
- Robert Jankowski
2020 Pełny tekst AIP Conference Proceedings
Steel grandstands are structures that are frequently used during sport games and many other non-sporting events, such as festivals, music concerts, or even politicians rallies, with participation of a large number of attendees. Unfortunately, the presence of unexpected excessive dynamic loads due to unpredictable behaviour of spectators (e.g. synchronized harmonic jumping or swaying) may lead to serious structural damage or even total collapse of a structure, and such cases were observed in the past. Given that, steel grandstands should be designed so as to withstand the unexpected dynamic loads leading to damage and, therefore, ensure maximum safety for all participants. Building codes, however, apply different approaches. According to the Polish Standard, an additional horizontal load equal to 6% of the total vertical load acting on a grandstand has to be considered at the design stage. The British Standard, on the other hand, specifies a higher value of horizontal load, i.e. 10% of the total vertical load that should be taken into account. Therefore, the aim of the present paper is to conduct a dynamic numerical investigation focused on the response of a steel temporary grandstand subjected to human-induced vibrations due to jumping with two different values of horizontal load (6% and 10% of the total vertical load) as well as for two different bracing elements (typical tubular member and polymer damper). The results of the study clearly show that the response of a temporary steel scaffolding grandstand equipped with two different bracing elements taking into account two different approaches is substantially different.
Dynamic Charging of Electric Buses as a Way to Reduce Investment Risks of Urban Transport System Electrification
- Mikołaj Bartłomiejczyk
- Marcin Połom
2020
Night charging and fast charging are currently the two most common systems for charging electric buses. Despite the fact that numerous trial installations were started, neither of these two systems has obtained unqualified approval of the users. The alternative is to charge vehicles in motion - dynamic charging which combines the advantages of trolleybus transport and of electric buses. One of the advantages is the reduction of risks associated with the electrifica-tion of urban transport. The investment in the construction of the traction net-work allows you to reduce the costs associated with the purchase and replace-ment of traction batteries, as well as increase the flexibility of the transport system. The article presents the financial benefits resulting from the use of a dynamic charging system.
Dynamic Response of the Suspended on a Single Cable Footbridge
- Mikołaj Miśkiewicz
- Łukasz Pyrzowski
- Krzysztof Wilde
2020
The article presents numerical simulations, dynamic in situ load tests and a structural health monitoring (SHM) system installed in a suspended on a single cable footbridge. Numerical simulations performed prior to construction indicated the possibility of structural dynamics problems, finally confirmed in the course of dynamic test loading. In the dynamic load course the bridge deck developed vibrations displaying accelerations up to 4.5 m/s2. Such footbridge behavior causes unacceptable discomfort to the users and risk of structural damage. The tests brought about the need for repair works and the use of a monitoring system to increase operational safety of the object.
Dynamic Tests and Technical Monitoring of a Novel Sandwich Footbridge
- Jacek Chróścielewski
- Mikołaj Miśkiewicz
- Łukasz Pyrzowski
- Magdalena Rucka
- Bartosz Sobczyk
- Krzysztof Wilde
- Błażej Meronk
2020
A novel sandwich composite footbridge is described in this paper, for the first time after it has been put into operation over the Radunia River in the Pruszcz Gdański municipality. This paper presents results of dynamic tests and describes technical monitoring of the footbridge. The dynamic tests were conducted to estimate pedestrian comfort and were compared with the ones from numerical simulations made in the environment of Finite Element Method. A discussion of the obtained results is made then. The characteristics and capabilities of the network of sensors spread over the bridge to monitor its long-term behavior are described.
Dziedzictwo 150 lat rozwoju techniki wodociągowej na terenie Gdańska i Sopotu
- Michał Klugmann
2020
Publikacja prezentuje historię nowoczesnych (czyli powstałych na fali rewolucji przemysłowej) wodociągów Gdańska i Sopotu. Wzmiankowane są najważniejsze zabytki techniki, związane z rozwojem systemu od II połowy XIX wieku. Na ich przykładzie poruszana jest szersza problematyka ochrony takich obiektów w polskich realiach. Opisany został zabytkowy zasób, w zakresie obiektów nieruchomych i dokumentacji, stan zachowania tego zasobu, działania dotychczas podjęte dla jego ochrony i elementy trwale utracone.
Early prediction of macrocrack location in concrete and other granular composite materials
- A. Tordesillas
- S. Kahagalage
- C. Ras
- Michał Nitka
- Andrzej Tejchman-Konarzewski
2020 Pełny tekst Scientific Reports
Heterogeniczne kruche kompozyty, takie jak beton, ceramika i skały składają się z ziaren połączonych wiązaniami. Pytanie, czy ścieżka pęknięcia, która prowadzi do zniszczenia może być przewidziania na podstawie znanych cech mikrostrukturalnych, a mianowicie łączności wiązań, rozmiaru, energii pękania, wytrzymałości pozostają otwarte. Istnieje wiele kryteriów pęknięć. Najczęściej używane są oparte na postulowanym ekstremum naprężenia i/lub energii. Ponieważ siła i energia mają wspólne ścieżki przekazu, ich wąskie gardło przepływu może być prekursorskim mechanizmem zniszczenia, które pogodzi te kryteria optymalności w jednej ujednoliconej strukturze. Badamy to w ramach teorii przepływu sieci, używając dane mikrostrukturalne z trójwymiarowych modeli elementów dyskretnych betonu podczas rozciągania jednoosiowego. Znajdujemy wąskie gardło siły i energii na tej samej ścieżce, które zapewnia wczesną i dokładną prognozę ostatecznej ścieżki makropęknięcia w betonie.
ECOLOGY OR ECONOMICS? THE ASPECT DETERMINING THE USE OF DISPLACEMENT PILES FOR THE FOUNDATIONS OF BRIDGE STRUCTURES
- Paweł Więcławski
- Kazimierz Gwizdała
2020 Pełny tekst
W ostatnich latach rzadko wykonuje się pale wiercone o bardzo dużych średnicach ze względu na: wymagany sprzęt, transport wydobytego urobku gruntowego, duże ilości stali zbrojeniowej. Konstrukcje inżynierskie na autostradzie A-1, na drodze ekspresowej S-7 i Obwodnicy Południowej Gdańska posadowiono na palach prefabrykowanych. Fundamenty największych mostów na autostradzie A-1 zbudowano na palach Vibro i Franki. W artykule zwrócono uwagę na pale w pełni przemieszczeniowe, charakteryzujące się dużą nośnością uzyskiwaną w krótkim czasie od wykonania i prostą technologią, które są stosowane w fundamentach obiektów drogowych. Spośród wszystkich, obecnie wykonywanych rodzajów pali, tę technologię można nazwać ekologiczną i ekonomiczną. Te aspekty mogą zmienić zakres zastosowania pali przemieszczeniowych w najbliższej przyszłości.
Ecotoxicological equilibria of triclosan inMicrotox, XenoScreen YES/YAS, Caco2, HEPG2 and liposomal systems are affected by the occurrence of other pharmaceutical and personal care emerging contaminants
- Miquel Oliver
- Błażej Kudłak
- Monika Wieczerzak
- Salette Reis
- Sofia Lima
- Marcela Segundo
- Manuel Miro
2020 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT
Contaminants of emerging concernmay be considered as any chemicals or factorswhose unintended continuous release and persistence in the environmentmay lead to any observable undesirable response of living beings. Still not much is known on reciprocal toxicological impact of given chemicals when present in binary or more complex mixtures. In thiswork, an attemptwas thus undertaken to study the impact of butylparaben,methylparaben and diclofenac on toxicological behavior and properties of triclosan (at varying concentration levels)with respect to Microtox, XenoScreen YES/YAS, Caco-2, HEPG2, and liposomal systems.
ECU calibration for gaseous dual fuel supply system in compression ignition engines
- Denys Stepanenko
- Zbigniew Kneba
2020 Pełny tekst Combustion Engines
The dual fuel (DF) combustion mode is proven solution that allows to improve or get at the same level engine performance and reduce toxic compounds in exhaust gases which is confirmed by researchers and end-users. DF combustion mode uses two fuels gaseous fuel as a primary energy source and a pilot quantity of diesel fuel as ignition source. However, in order, to fully take advantage of the potential of the dual fuel mode, DF system must be proper calibrated. Despite the existence of commercial control systems for dual fuel engines on the market, the literature on the important parameters for the engine's operation introduced during calibration is scarce. This article briefly describes a concept of working algorithm and calibration strategy of a dual fuel electronic control unit (ECU) The purpose of calibration is to achieve the greatest possible use of an alternative gaseous fuel without causing accelerated engine wear.
Editorial for the special issue on advances in forward and inverse surrogate modeling for high-frequency design
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
2020 INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS
The design of modern‐day high‐frequency devices and circuits, including microwave/RF, antenna and photonic components, historically has relied on full‐wave electromagnetic (EM) simulation tools. Initially used for design verification, EM simulations are nowadays used in the design process itself, for example, for finding optimum values of geometry and/or material parameters of the structures of interest. In a growing number of cases, EM‐driven design closure is mandatory because alternative ways of evaluating the circuit performance (such as through equivalent network modeling) are grossly inaccurate and unable to account for cross‐coupling effects (eg, in densely arranged layouts of compact circuits or antenna arrays), or various environmental components that affect the circuit performance (eg, connectors or housing for antenna structures). Despite being imperative, simulation‐based design poses significant challenges, mostly due to the high computational cost of accurate, high‐fidelity analysis. Repetitive simulations entailed by conventional optimization routines and even more by uncertainty quantification procedures (eg, Monte Carlo analysis) or tolerance‐aware design tasks may generate the costs that are unmanageable or at least impractical. The availability of massive computational resources does not always translate into design speedup due to the need to account for interactions between devices and their surroundings as well as multiphysics (eg, EM‐thermal) effects.
EduAkcja. Historia pewnego czasopisma
- Agnieszka Landowska
- Maria Wilkin
2020
Rozdział przedstawia przebieg inicjatywy powołania czasopisma poświęconego zdalnemu nauczaniu o nazwie EduAkcja. Magazyn edukacji elektronicznej
E-dyplomy: uwarunkowania administracyjne i funkcjonalne ich wprowadzenia na polskich uczelniach
- Wioletta Braun
- Katarzyna Górak-Sosnowska
2020
Pandemia COVID-19 wymusiła na polskim systemie szkolnictwa wyższego szereg zmian, z których główne dotyczą zmian w zakresie organizacji pracy, cyfryzacji procesów obsługi toku studiów. Przepisy prawa stanowią już o e-teczce, mamy rozporządzenia dotyczące jej prowadzenia, niemniej niewiele uczelni, o ile w ogóle, prowadzi na chwilę obecną akta osobowe studentów w postaci elektronicznej. Jednym z elementów składowych e-teczki jest dyplom ukończenia studiów. Publikacja traktuje o obecnym systemie prawnym dotyczącym dyplomów oraz e-dyplomów. Wskazuje na konieczność wprowadzenia dodatkowych zapisów prawnych, które umożliwiłyby na wdrożenie tego rozwiązania. W artykule dokonano również przeglądu istniejących rozwiązań stosowanych w innych krajach i ewentualnych potencjalnych istniejących możliwościach cyfrowego odwzorowania dyplomu. Wprowadzenie e-dyplomów, bądź do ich całkowitego wdrożenia cyfrowych odwzorowań tych dokumentów, jest kwestią czasu. W artykule wskazano na potencjalne ścieżki procedowania tego rozwiązania.
E-Estonia as a role model? Some general considerations and applicability in France
- Aleksandro Cepilovs
- David Duenas Cid
2020
Estonia has recently been widely recognised – in the policy circles, academia, as well as the media space – as one of the more advanced nation states when it comes to digital government (and governance) transformation (e.g. Margetts and Naumann, 2017; Heller, 2017). Ever greater attention Estonia attracted with the two most recent digital government initiatives, namely the e-Residency and the virtual data embassy, both first of their kind in the world. Estonia thus placed itself among such leaders in digital government as Singapore and Denmark, despite the fact that it is both significantly smaller as well as relatively poorer in terms of GDP per capita1. This high level of development of digital government seems even more surprising considering the fact that Estonia has re-gained its independence less than 30 years ago.
Effect of Aromatic System Expansion on Crystal Structures of 1,2,5-Thia- and 1,2,5-Selenadiazoles and Their Quaternary Salts: Synthesis, Structure, and Spectroscopic Properties
- Jan Alfuth
- Beata Zadykowicz
- Artur Sikorski
- Tadeusz Połoński
- Katarzyna Eichstaedt
- Teresa Olszewska
2020 Pełny tekst Materials
Rational manipulation of secondary bonding interactions is a crucial factor in the construction of new chalcogenadiazole-based materials. This article reports detailed experimental studies on phenanthro[9,10-c][1,2,5]chalcogenadiazolium and 2,1,3-benzochalcogenadiazolium salts and their precursors. The compounds were synthesized, characterized employing NMR and UV-Vis spectroscopy. TD-DFT calculations were also performed. The influence of the size of the aromatic system on the molecular motifs formed by the compounds in the solid state has been studied by means of single-crystal X-ray diffraction. In case of the salts, the nature of an anion was also taken into consideration. The results show that cyclic [E···N]2 supramolecular synthon connects neighboring molecules of phenanthro[9,10-c][1,2,5]chalcogenadiazoles, with a relatively large aromatic system, in dimers regardless of the chalcogen atom in the molecule. Both N-methyl-2,1,3-benzothiadiazolium and N-methylphenanthro[9,10-c][1,2,5]chalcogenadiazolium cations have a strong affinity for triflate and iodide anions, therefore the formation of S···N or Se···N secondary bonding interactions is observed only in two out of the eight quaternary salts. Less coordinating anions must be used to enable the building blocks studied to form cyclic [E···N]2 synthons. Moreover, for two of the triflate salts, which are isostructural, a new supramolecular motif has been observed.
Effect of Axial Porosities on Flexomagnetic Response of In-Plane Compressed Piezomagnetic Nanobeams
- Mohammad Malikan
- Victor Eremeev
- Krzysztof Kamil Żur
2020 Pełny tekst Symmetry-Basel
We investigated the stability of an axially loaded Euler–Bernoulli porous nanobeam considering the flexomagnetic material properties. The flexomagneticity relates to the magnetization with strain gradients. Here we assume both piezomagnetic and flexomagnetic phenomena are coupled simultaneously with elastic relations in an inverse magnetization. Similar to flexoelectricity, the flexomagneticity is a size-dependent property. Therefore, its effect is more pronounced at small scales. We merge the stability equation with a nonlocal model of the strain gradient elasticity. The Navier sinusoidal transverse deflection is employed to attain the critical buckling load. Furthermore, different types of axial symmetric and asymmetric porosity distributions are studied. It was revealed that regardless of the high magnetic field, one can realize the flexomagnetic effect at a small scale. We demonstrate as well that for the larger thicknesses a difference between responses of piezomagnetic and piezo-flexomagnetic nanobeams would not be significant.
Effect of band gap on power conversion efficiency of single-junction semiconductor photovoltaic cells under white light phosphor-based LED illumination
- Grażyna Jarosz
- Rafał Marczyński
- Ryszard Signerski
2020 Pełny tekst MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
On the basis of the detailed balance principle, curves of efficiency limit of single-junction photovoltaic cells at warm and cool white light phosphor-based LED bulbs with luminous efficacy exceeding 100 lm/W have been simulated. The effect of energy band gap and illuminance on the efficiencies at warm and cool light is discussed. The simulations carried out show that maximum power conversion efficiency at 1000 lx reaches 52.0% for cool light and 53.6% for warm one, while the optimal energy band gap is 1.80 eV and 1.88 eV, respectively. The simulated limits are also referenced to experimental data presented in literature to show that there is still a lot of room for improving indoor photovoltaic cells.