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Mechanical Properties of Twisted Carbon Nanotube Bundles with Carbon Linkers from Molecular Dynamics Simulations
PublikacjaThe manufacturing of high-modulus, high-strength fibers is of paramount importance for real-world, high-end applications. In this respect, carbon nanotubes represent the ideal candidates for realizing such fibers. However, their remarkable mechanical performance is difficult to bring up to the macroscale, due to the low load transfer within the fiber. A strategy to increase such load transfer is the introduction of chemical linkers...
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Surface studies of twinned of YBa2Cu3O7−δ crystals
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Should patients with sudden deafness be tested for COVID19?
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Marketing terytorialny a social media marketing na serwisie Twitter
PublikacjaObszary terytorialne, podobnie jak inne podmioty gospodarcze, walczą o miejsce na rynku. Poprzez promocję dążą do osiągnięcie uprzywilejowanych miejsc w świadomości interesariuszy, będących dla danego regionu inwestorami, bądź turystami, którzy chcą miło spędzić czas na wakacjach. Miasta kreują swój wizerunek i dbają o niego, budując więzi emocjonalne i lojalność wobec swoich klientów. W tym celu wykorzystane są różne rodzaje instrumentów...
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Migrants vs. stayers in the pandemic – A sentiment analysis of Twitter content
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The Ownership Structure and the Performance of the Polish Stock Listed Companies
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Examining Government-Citizen Interactions on Twitter using Visual and Sentiment Analysis
PublikacjaThe goal of this paper is to propose a methodology comprising a range of visualization techniques to analyze the interactions between government and citizens on the issues of public concern taking place on Twitter, mainly through the official government or ministry accounts. The methodology addresses: 1) the level of government activity in different countries and sectors; 2) the topics that are addressed through such activities;...
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Estimation of Stresses in a Dry Sand Layer Tested on Shaking Table
PublikacjaTheoretical analysis of shaking table experiments, simulating earthquake response of a dry sand layer, is presented. The aim of such experiments is to study seismic-induced compaction of soil and resulting settlements. In order to determine the soil compaction, the cyclic stresses and strains should be calculated first. These stresses are caused by the cyclic horizontal acceleration at the base of soil layer, so it is important...
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CSR – A FASHION OR REAL COMMITMENT? THE CASE OF POLISH LISTED COMPANIES
PublikacjaThis article, without claiming to be the ultimate reference, aims at assessing the social commitment of the large and solid financially, listed on the Warsaw Stock Exchange (WSE), Polish companies, on the eve of the implementation of the EU directive on disclosure of non-financial and diversity information (2014/95/EU). The selected companies seem perfect to form a vanguard of CSR in Poland, but the results of the analysis indicate...
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On Radar DoA Estimation and Tilted Rotating Electronically Scanned Arrays
PublikacjaWe consider DoA estimation in a monopulse radar system employing a tilted rotating array. We investigate the case of nonzero steering angles, in which case the mapping between the target’s azimuth and elevation in the global coordinate system and their counterparts in the array local coordinate system becomes increasingly nonlinear and coupled. Since estimating the azimuth using coherently integrated signals might be difficult because...
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Analyzing and Visualizing Government-Citizen Interactions on Twitter to Support Public Policy-making
PublikacjaTwitter is widely adopted by governments to communicate with citizens. It has become a major source of data for analyzing how governments communicate with citizens and how citizens respond to such communication, uncovering important insights about government-citizen interactions that could be used to support public policy-making. This article presents research that aims at developing a software tool called Twitter Analytics for...
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Mapping of the Covid-19 Vaccine Uptake Determinants From Mining Twitter Data
PublikacjaOpinion polls on vaccine uptake clearly show that Covid-19 vaccine hesitancy is increasing worldwide. Thus, reaching herd immunity not only depends on the efficacy of the vaccine itself, but also on overcoming this hesitancy of uptake in the population. In this study, we revealed the determinants regarding vaccination directly from people’s opinions on Twitter, based on the framework of the 6As taxonomy. Covid-19 vaccine acceptance...
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Tyre/road noise reduction of poroelastic road surface tested in a laboratory
PublikacjaA so-called poroelastic road surface (PERS) is being developed in Europe. This contains a large percentage of rubber particles mixed with hard aggregate (stone and sand) and bound with polyurethane. This gives high air void content (around 30 %), high elasticity and smooth texture, all of which should give low noise properties. Inthis experiment anominally 30 mm thick sample of PERS was mounted on a steel drum. Various car tyres...
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The high-cyclic model for sand tested beyond the usual ranges of application
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Blade Section Prpfile Array Lifting Surface Design Method for Marine Screw Propeller Blade
PublikacjaThe lifting surface model is widely used in screw propeller design and analysis applications. It serves as a reliable tool for determination of the propeller blade mean line and pitch distribution. The main idea of this application was to determine the blade shape that would satisfy the kinematic boundary condition on its surface with the prescribed bound circulation distribution over it. In this paper a simplified lifting surface...
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Ruthenium(II) and Iridium(III) Complexes as Tested Materials for New Anticancer Agents
PublikacjaThe oncological use of cisplatin is hindered by its severe side eects and a very important resistance problem. To overcome these problems, scientists have attempted to design new generation transition-metal anticancer complexes. In this study, we present new complexes, ruthenium(II) [(6-p-cymene)RuCl(py2CO)]PF6 (1), iridium(III) [(5-Cp)IrCl(py2CO)]PF6 (2), and NH4[IrCl4(py2CO)]H2O (3), based on di-2-pyridylketone (py2CO). The prepared...
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Twitter jako narzędzie wspierające działania promocyjne szkół wyższych. Przykład Biblioteki Politechniki Gdańskiej
PublikacjaSerwis społecznościowy Twitter wydaje się być skutecznym narzędziem wspierającym nie tylko promowanie dorobku poszczególnych pracowników naukowych uczelni. Może być on także wykorzystywany do prowadzenia działań upowszechniających, promujących i popularyzujących wyniki działalności badawczo-rozwojowej, innowacyjnej i wynalazczej szkół wyższych w skali krajowej oraz międzynarodowej. Biblioteka akademicka może stanowić ważne wsparcie...
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Pressure Pulsations in Turbine Blade Seal
PublikacjaThe paper presents the results of experimental investigations into pressure forces generated in a turbine labyrinth seal. The experiments were performed on a single-stage air model turbine of the impulse type. The performed experimental research proved that in a shroud clearance the pressure pulsates and the effects of the nozzle trailing edge thickness as well as the influence of the rotor blades are observed. The exemplary results...
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Inverse method for axisymmetric and blade-to-blade viscous flow models in cylindrical coordinates using stream-function transformation
PublikacjaZaproponowano nową metodę odwrotną rozwiązywania dwuwymiarowych zagadnień projektowych we współrzędnych cylindrycznych. Użyto współrzędnych funkcji prądu uzależniając kształt opływanej geometrii od kształtu linii prądu. Metodę zwalidowano. Pokazano zastosowanie do przepływów osiowosymetrycznych jak i na powierzchniach cylindrycnych.
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Corporate Governance and Ownership Structure in the Top 30 Listed Non Financial Companies in Poland
PublikacjaThis paper offers a first analysis of the relationships between corporate governance models and rules and ownership structure of the top 30 Polish firms listed at the WSE (not considering foreign firms and/or the Polish branches of foreign firms listed at the same stock exchange, nor the financial companies and the banks). The general picture depicted by this analysis is putting into evidence the increasing importance of institutional...
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The role of intermolecular interactions in stabilizing the structure of the nematic twist-bend phase
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A Method for Optimising the Blade Profile in Kaplan Turbine
PublikacjaThis paper introduces a method of blade profile optimisation for Kaplan-type turbines, based on modelling the interaction between rotor and stator blades. Rotor and stator blade geometry is described mathematically by means of a midline curve and thickness distribution. Genetic algorithms are then used to find a global optimum that minimises the loss coefficient. This allows for variety of possible blade shapes and configurations....
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Rotor Blade Geometry Optimisation in Kaplan Turbine
PublikacjaThe paper presents the description of method and results of rotor blade shape optimisation. The rotor blading constitutes a part ofturbine flow path. Optimisation consists in selection of the shape that minimises ratio of polytrophic loss. Shape of the blade isdefined by the mean camber line and thickness of the airfoil. Thickness is distributed around the camber line based on the ratio ofdistribution. Global optimisation was done...
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Circular saw blade dynamics - the measurement method
PublikacjaW pracy przedstawiono przyczyny i efekty zmiany położenia ostrzy piły tarczowej w układzie przecinania. Przedstawiony sposób pomiaru dynamiki piły tarczowej umożliwia określenie przyczyn drgań, co stanowi podstawę skutecznej ich minimalizacji.
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Pressure pulsations in turbine blade seal clearance
PublikacjaThe paper presents the results of numerical and experimental investigations into pressure forces generated in a turbine labyrinth seal. The experiments were performed on a single-stage air model turbine of the impulse type, while the numerical results were obtained by means of CFD Fluent Code. The performed experimental research and numerical calculations prove that in a shroud clearance the pressure pulsates and the effects of...
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Some approaches to the determination of saw blade stiffness.
PublikacjaW nowoczesnych zakładach przerobu drewna obserwuje się tendencję do redukcji rzazu w celu ograniczenia strat surowca. Jednakże, cienkie piły są bardziej wrażliwe na odziaływanie sił odporowych (bocznych). Dlatego też, znajomość sztywności statycznej pozwala użytkownikowi prognozować zachowanie się piły podczas pracy. W pracy przedstawiono metodykę wyznaczania sztywności statycznej początkowej i roboczej pił trakowych oraz taśmowych....
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Laser-assisted modification of titanium dioxide nanotubes in a tilted mode as surface modification and patterning strategy
PublikacjaElectrochemical anodization is regarded as a facile and easily scalable fabrication method of titania nanotubes (TiO2NTs). However, due to the extended duration of calcination and further modifications, much faster alternatives are highly required. As a response to growing interest in laser modification of nanotube arrays, a comprehensive investigation of pulsed-laser irradiation and its effect onto TiO2NT properties has been carried out....
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Field investigations of stack ventilation in a residential building with multiple chimneys and tilted window in cold climate
PublikacjaArtykuł przedstawia wyniki pomiarów wykonanych w budynku mieszkalnym w północnej Polsce w zimnym klimacie podczas zimy i lata. Budynek zawierał kominy i uchylne okna. Pomierzono lokalne i wewnętrzne warunki klimatu oraz prędkości powietrza. Zaproponowano zmodyfikowany model uchylnych okien oparty na modelu wentylacji jednokierunkowej.
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What do hashtags afford in digital fashion communication? An exploratory study on Gucci-related hashtags on Twitter and Instagram.
PublikacjaBeing enmeshed in a digital environment, we daily produce internet-mediated texts – encompassing several different semiotic codes – accessible on a global scale. Posts on different networks usually contain hashtags, which can be understood as affordances or behavior opportunities. These affordances allow specific actions both from the part of the writer and the reader. They can also be “behavior triggers,” which invite certain...
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How Do Intermolecular Interactions Evolve at the Nematic to Twist–Bent Phase Transition?
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Computational method for determining the static stiffness of the saw blade
PublikacjaW artykule opisano sposób modelowania i obliczeń odkształceń i naprężeń pił tarczowych o złożonej geometrii korpusu z wykorzystaniem komputerowych programów wspomagających projektowania.
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Effect of the saw blade geometry at its static stiffness
PublikacjaW artykule opisano wpływ wybranych parametrów piły tarczowej wpływających w istotny sposób na jej sztywność statyczną.
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An assessment of teeth quality of the mini gang saw blade
PublikacjaIn this work, the assessment of the effect of the operating time (90 min.) of the mini gang saw blades during sawing Scotch pine (Pinus sylvestris L.) samples upon changes of the saw blade teeth sharpness (bluntness), which was defined as an effective radius of the nose ρ , has been described. The research activities have been carried out on the Nikon Ti-S optical microscope equipped with the Nikon DS-30W camera allowing high-speed...
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Usability of calculation methods for saw blade stiffness determination.
PublikacjaW pracy przedstawiono metodykę wyznaczania sztywności poprzecznej pił określanej na linii zębów. Prezentowana metodyka może być wykorzystywana zarówno do pił trakowych jak i taśmowych. Podano zalecenia wyboru odpowiedniej metody obliczeniowej w zależności od szerokości brzeszczotu piły.
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Theoretical investigations into flows in rotor blade shroud clearance
PublikacjaPrzedstawiono wyniki obliczeń programem Fluent przepływów w uszczelnieniu nadbandażowym stopnia turbinowego przy różnym mimośrodowym położeniu osi wirnika względem osi korpusu. Wyznaczone numerycznie rozkłady ciśnienia w uszczelnieniu i generowane tam siły aerodynamiczne porównano z rezultatem badań przeprowadzonych na powietrznej turbinie modelowej.
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Modeling of cut layer's thickness for circular saw blade
PublikacjaW pracy omówiono sposób modelowania grubości warstwy skrawanej na podstawie wyprowadzonych zależności matematycznych.
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Suitableness of SLM Manufactured Turbine Blade for Aerodynamical Tests
PublikacjasettingsOrder Article Reprints Open AccessArticle Suitableness of SLM Manufactured Turbine Blade for Aerodynamical Tests by Janusz Telega 1,*ORCID,Piotr Kaczynski 1ORCID,Małgorzata A. Śmiałek 2ORCID,Piotr Pawlowski 3ORCID andRyszard Szwaba 1ORCID 1 Institute of Fluid Flow Machinery Polish Academy of Sciences (IMP PAN), Fiszera 14, 80-231 Gdansk, Poland 2 Faculty of Mechanical Engineering and Ship Technology, Institute of Naval...
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Regulated Emissions, Unregulated Emissions and Fuel Consumption of Two Vehicles Tested on Various Petrol-Ethanol Blends
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Europe, between Mandatory and Voluntary Approach to CSR: Some New Evidence from the Polish Listed Companies
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Review of the Usefulness of Various Rotational Seismometers with Laboratory Results of Fibre-Optic Ones Tested for Engineering Applications
PublikacjaStarting with descriptions of rotational seismology, areas of interest and historical field measurements, the fundamental requirements for rotational seismometers for seismological and engineering application are formulated. On the above basis, a review of all existing rotational seismometers is presented with a description of the principles of their operation as well as possibilities to fulfill formulated requirements. This review...
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Europe, between Mandatory and Voluntary Approach to CSR: Some New Evidence from the Polish Listed Companies
PublikacjaThis paper aims to explore the relationship between corporate governance rules and application of CSR practices into operations of the top 30 companies listed on the Warsaw Stock Exchange. Since in Poland, so far, there is no obligation to follow any specific CSR standards or to make disclosures of non-financial, social and environmental information, this is still a fully voluntary approach. At the moment, only some of the companies...
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Numerical evaluation of dynamic response of an experimentally tested base-isolated and fixed-base steel structure model
PublikacjaSeismic isolation is recognized as one of the most popular and effective methods of protecting structures during earthquake. The present paper is focused on the comparison be-tween the dynamic responses of buildings with fixed and isolated bases exposed to seismic exci-tations. The aim of the study is to investigate the effectiveness of a simplified base isolation numerical modelling technique using the linear springs. One-storey...
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Analysis of the state of preservation the historic arcaded houses in Vistula Delta listed in the National Inventory of Historical Monuments
PublikacjaHistoric arcaded houses are part of the material heritage of the Vistula Delta. Unfortunately, their number is decreasing year by year. The article is the result of a query of available sources and field research carried out by the author in 2015-2020. The paper presents the current state of preservation the historic arcaded houses in Vistula Delta listed in the National Inventory of Historical Monuments. Criteria for the selection...
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Approval of an Arrangement in the Restructuring Proceedings and the Financial Condition of Companies Listed on the Stock Exchanges in Warsaw. Is There Any Relationship?
PublikacjaThis paper attempts to identify the financial indicators differentiating companies that are insolvent or at risk of insolvency and have successfully entered into an arrangement with their creditors from those that have not. In addition, a two-factor model for predicting the odds of an arrangement has been proposed. The research was conducted using a population of companies listed on stock exchanges in Warsaw that initiated restructuring...
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Dielectric response of electric-field distortions of the twist-bend nematic phase for LC dimers
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Numerical Analysis of Twist Extrusion Pressing of Al-Mg-Mn-Sc-Zr Scalmalloy
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Investigations into Particulate Emissions from Euro 5 Passenger Cars with DISI Engines Tested at Multiple Ambient Temperatures
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DESIGN AND CONSTRUCTION OF TILTED WALLS IN ACCORDANCE WITH CODES' PROVISIONS ON THE EXAMPLE OF THE CONSTRUCTION OF THE MUSEUM OF THE SECOND WORLD WAR IN GDAŃSK
PublikacjaThe purpose of this article was to introduce the design and construction of tiled walls in accordance to codes' restrictions. The construction of the Museum of the Second World War in Gdańsk was chosen to be an example of its successful use in practice. Theoretical knowledge was based on PN-EN 1992-1-1:2008 and fib Model Code for Concrete Structures 2010. Although codes' recommendations seem curt, practice prove structural advance....
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Improving Savonius rotor performance by shaping its blade edges
PublikacjaThe article presents the results of the numerical analysis of the flow inside the Savonius rotor. Particular at-tention has been paid to the vicinity of the blade gap in order to recognise the mechanisms controlling the flow in this area. The conclusions resulting from the analysis made the basis for an attempt to improve Savonius turbine performance via shaping rotor blade edges. The paper presents selected characteristic flow...
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The Method of Reduction of Aerodynamic Forces Generated in Turbine Blade Seals
PublikacjaOpisano metodę zmniejszania sił wymuszających drgania aerodynamiczne poprzez zastosowanie nowego uszczelnienia nadbandażowego typu komorowego. Efektywność stosowania uszczelnienia komorowego potwierdzono obliczeniami numerycznymi i badaniami eksperymentalnymi.