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Search results for: PASSIVE COMPENSATION
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Hydrogen Damage in Superaustenitic 904L Stainless Steels
Publicationresults on the influence of hydrogen on corrosion resistance and of hydrogen embrittlement of 904L superaustenitic stainless steel were investigated. The cracking behavior was studied by performing a slow strain rate test in synthetic seawater under varying cathodic polarization conditions. The results showed that the steel’s plasticity varied with the applied cathodic current density. Significant reductions in ductility were found,...
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An Efficient Framework For Fast Computer Aided Design of Microwave Circuits Based on the Higher-Order 3D Finite-Element Method
PublicationIn this paper, an efficient computational framework for the full-wave design by optimization of complex microwave passive devices, such as antennas, filters, and multiplexers, is described. The framework consists of a computational engine, a 3D object modeler, and a graphical user interface. The computational engine, which is based on a finite element method with curvilinear higher-order tetrahedral elements, is coupled with built-in...
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The effect of pre-hydrogen charging on corrosion behaviour of superduplex stainless steel welded joints
PublicationThe paper presents results of research undertaken to determine the influence of hydrogen on passivity and corrosion resistance of 2507 super duplex stainless steel welded joints. Butt welded joints were made with low heat input using flux corded arc welding (FCAW) method. Coupons of 5.0 x 5.0 mm were cut from the welded joints containing weld metal (WM), heat affected zone (HAZ) and parent metal (PM). Hydrogen was introduced...
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The effect of anthropogenic activity on BTEX, NO2, SO2, and CO concentrations in urban air of the spa city of Sopot and medium-industrialized city of Tczew located in North Poland
PublicationThe major goal of the present study is to compare the air quality of two urban locations situated in Northern Poland – the spa City of Sopot and the medium-industrialized city of Tczew using chemometric methods. As a criterion for the assessment of atmospheric air quality, measurements of benzene, toluene, ethylbenzene and total xylenes were used (collected from atmospheric air using diffusion-type passive samplers) as well as...
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Experimental study on single phase operation of microjet augmented heat exchanger with enhanced heat transfer surface
PublicationThe article presents experimental investigations on a prototype heat exchanger. Presented research is focused on combined active and passive enhancement techniques of surface modification and microjet impingement. The results were compared to reference plate heat exchanger without microjet impingement. The Wilson plot method was applied to determine the heat transfer coefficients in the single phase operation. The heat exchanger...
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Radar Signal Parameters Estimation Using Phase Accelerogram in the Time-Frequency Domain
PublicationRadar signal parameter estimation, in the context of the reconstruction of the received signal in a passive radar utilizing other radars as a source of illumination, is one of the fundamental steps in the signal processing chain in such a device. The task is also a crucial one in electronic reconnaissance systems, e.g. ELINT (Electronic Intelligence) systems. In order to obtain accurate results it is important to measure, estimate...
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Koncepcja połączenia kolejowego Morskiego Portu Gdynia S.A. z Kolejową Obwodnicą Trójmiasta
PublicationZapotrzebowanie na połączenie rozwijającego się Morskiego Portu Gdynia z Kolejową Obwodnicą Trójmiasta. Utworzenie tak zwanych „długich pociągów”. Wpływ katastrof kolejowych na warunki gruntowe i środowisko. Potrzeba modernizacji linii kolejowych. Kolejowa Obwodnica Trójmiasta jako alternatywa dla przejazdu pociągów przez obszar Aglomeracji Trójmiejskiej.
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Nash capacity of an ad hoc IEEE 802.11 LAN
PublicationNa podstawie analizy mechanizmów motywujących stacje bezprzewodowej sieci lokalnej do rekonfiguracji protokołu MAC obliczono przepływność sieci w punkcie równowagi Nasha.Założono, że stacje sieci maksymalizują swoje udziały w pasmie transmisyjnym poprzez wybór okien rywalizacji.
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ZAAWANSOWANE SYMULACJE NUMERYCZNE MES DYNAMIKI MOSTÓW Z WYKORZYSTANIEM PROCEDURY EXPLICITE
PublicationDostęp do mocy obliczeniowej superkomputerów oraz możliwość wykorzystania nowoczesnych systemów, np. takich jak Ls-Dyna, pozwala na uzyskanie niezwykle szczegółowych rozwiązań bardzo skomplikowanych problemów inżynierskich. Zagadnienia te dotyczą zakresu statyki/stateczności jak i dynamiki dla rozbudowanych układów konstrukcyjnych zarówno w zakresie nieliniowości materiałowej jak i geometrycznej. Uzyskanie wiarygodnych wyników...
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Euro 2012 in Gdańsk, Poland. Is it worth using public funds?
PublicationThe aim of this study is to estimate the willingness - to - pay (WTP) among the community of the Pomeranian region, Poland in connection with intangible benefits and costs st emming from hosting the Euro 2012 in Gdansk. A survey conducted among 407 respondents was the source of information. The results of the study show that the average value of WTP benefit for the whole sample was 45,72 PLN2012 and WTP cost...
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INTENSYFIKACJA WYMIANY CIEPŁA W WYMIENNIKU WĘŻOWNICOWYM Z WYKORZYSTANIEM PRZEGRÓD O RÓŻNEJ GEOMETRII
PublicationW pracy zaprezentowano możliwości wykorzystania pasywnej intensyfikacji wymiany ciepła w postaci przegród dla podniesienia efektywności energetycznej wymiennika wężownicowego. Badania zostały przeprowadzone z wykorzystaniem modułowego wymiennika z wężownicą w postaci grzałki elektrycznej. Medium odbierającym ciepło była woda o stałych parametrach cieplnoprzepływowych na wlocie do modułu. Pomiary przeprowadzono dla szerokiego zakresu...
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WYKORZYSTANIE TESTU MUSHRA W BADANIU KORZYŚCI UŻYTKOWANIA PROTEZ SŁUCHOWYCH
PublicationOcena jakości dopasowania aparatów słuchowych w kontekście korzyści, jakie może przy-nieść proteza jest złożonym zagadnieniem. Obiektywne parametry aparatów, które można wy-znaczyć (np. wzmocnienie czy pasmo przenoszenia) nie zawsze mają bezpośredni i decydujący wpływ w subiektywnej ocenie jakości dopasowania protezy słuchowej przez pacjenta. Pomiary efektywności aparatu słuchowego mogą dotyczyć wielu aspektów, między innymi kompensacji...
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Performance of the domestic micro ORC equipped with the shell-and-tube condenser with minichannels
PublicationIn this paper, the original compact shell-and-tube heat exchanger with circular minichannels of in-house design and manufacturing is presented as the condenser for the domestic micro heat and power plant investigations as well as other future technical applications. The heat exchanger is equipped with turbulizing baffles inside the shell. The shell itself is made of a tubular sleeve having an inner diameter of 0.067 m and the length...
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Badanie i analiza anten PCB w zastosowaniu ich w urządzeniach o ograniczonych rozmiarach
PublicationNiniejsze opracowanie zawiera wyniki przeprowadzonych badań dotyczących drukowanych anten o niewielkich rozmiarach. Celem tych badań było wytypowanie anten pracujących w pasmie 868MHz, które mogłyby znaleźć zastosowanie w urządzeniach do monitorowania położenia osób w środowiskach zamkniętych.
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ADOPTED ISOCHRONE METHOD IMPROVING SHIP SAFETY IN WEATHER ROUTING WITH EVOLUTIONARY APPROACH
PublicationThe paper is focused on adaptation of an isochrone method necessary for application to a weather routing system with evolutionary approach. Authors propose an adaptation of the isochrone method with area partitioning assuring that the route found by the adopted method would not cross land. In result, when applied to a weather routing system with evolutionary approach, this proposal facilitates creation of initial population, resulting...
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The influence of ammonia and selcted amines on the characteristics of calcium carbonate precipitated from calcium chloride solutions via carbonation
PublicationThe precipitation of calcium carbonate was carried out by passing a gasous mixture of carbon dioxide and air into a calcium chloride solution. The selected compounds enhancing carbon dioxide absorption were used as additives which promote the formation of carbonate ions in the solution. The additives were ammonia, monoethanolamine, triethylamine and triethanolamine. The resulting calcium carbonate particles varied in polymorphic...
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Analytical studies of spectrum broadcast structures in quantum Brownian motion
PublicationSpectrum broadcast structures are a new and fresh concept in the quantum-to-classical transition, introduced recently in the context of decoherence and the appearance of objective features in quantum mechanics. These are specific quantum state structures, responsible for the objectivization of the decohered state of a system. Recently, they have been demonstrated by means of the well-known quantum Brownian motion model of the recoilless...
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Numerical Analysis of Mice Carotid Arteries’ Response Emphasizing the Importance of Material Law Constants’ Validation
PublicationIn this paper, a detailed validation of the passive material properties of mice carotid arteries and constants of the Fung and Holzapfel hyperelastic material laws is conducted by means of static nonlinear FEM analyses. The response of the carotid arteries in an inflation test is studied here for the following mouse models: wild-type, mdx, sgcd−/−, Eln+/+, Eln+/−, Fbln5+/+, and Fbln5−/−. All FEM computations are conducted on models...
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Design of Frequency-Reconfigurable Branch-Line Crossover Using Rectangular Dielectric Channels
PublicationThis paper presents an efficient yet straightforward passive reconfiguration technique to tune the operating frequency of a branch-line crossover (BLCO). The underlying principle is to fill rectangular dielectric channels (RDCs) prepared beforehand with either air or materials of different relative permittivity. Two configurations (one RDC and three RDCs in each arm) of the branch-line crossover are employed to estimate the tunability...
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Searching for innovation knowledge: insight into KIBS companies
PublicationThe paper analyses the activity of research for “innovation knowledge”—here defined as knowledge that can lead to the introduction of service innovations—by Knowledge-Intensive Business Services (KIBS) companies. It proposes a classification of the possible search approaches adopted by those companies based on two dimensions: the pro-activity of search efforts and the source primarily used. Such classification is then discussed...
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Determination of cyanide in urine and saliva samples by ion chromatography with pulsed amperometric detection
PublicationCommonly known as a highly toxic chemical, cyanide is also an essential reagent for many industrial processes. It naturally occurs in plant seeds as a cyanogenic glycosides. Another relatively common mode of cyanide exposure is inhalation of environmental tobacco smoke. This study concerns importance to determine cyanide ion in human biological samples. Urine and saliva samples were collected healthy volunteers exposed to tobacco...
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Determination of cyanide ion in urine samples using ion chromatography with pulsed amperometric detection.
PublicationCyanides are widely applied in industrial activity, including gold and silver mining and the production of organic chemicals. HCN is also formed directly from fossil fuel combustion sources from gasoline and diesel vehicles. In natural environment, in plants seeds for example an apple seed, it exists as a cyanogenic glycosides. The amount of cyanide ions originating from food products is however rather small. Larger concentrations...
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Smart acoustic band structures
PublicationSmart acoustic band structures exhibit very interesting and non-standard physical properties due to the periodic nature of their certain characteristic on different scale levels. They manifest mostly in their frequency spectra as socalled frequency band-gaps or stop-bands, what has a great impact on the behaviour of these structures in relation to the propagation of vibro-acoustic signals that can be transmitted through the structures...
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Controlled Random Search Applied to Parameters Estimation of the Longitudinal Solutes Transport Model for Rivers
PublicationNumerical computations are presented for the longitudinal transport of passive, conservative solutes in an actual river with the inclusion of geometrical complexities of river channels. A special emphasis is put on the method of the identification of model parameters which is based on a specially designed optimisation procedure using random control search algorithm. Two different situations are considered namely a linear version...
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SILICA AEROGEL TOWARDS ANODES FOR LITHIUM-ION BATTERIES
PublicationAn increasing demand for electrochemical energy storage and conversion devices stimulates progress in research on electrode and electrolyte materials. In the field of electrodes materials, silicon is the one of the most promising anode materials for Li-ion batteries. However silicon has the drastic volume variation (around 3 times lower on extraction) during insertion and extraction of lithium ions. As an alternative, nanocomposites...
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Characterization of Arctic Driftwood as Naturally Modified Material. Part 1: Machinability
PublicationArctic driftwood has reached the coast of Iceland for centuries. This material was used by the inhabitants of the island as a building material for houses, boats, churches and pasture fences. Nowadays, the driftwood is used in the furniture industry, for the finishing of internal and external walls of buildings and also by artists. The properties of driftwood differ to that of original resource due the long-term effects of exposure...
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Online sound restoration system for digital library applications.
PublicationAudio signal processing algorithms were introduced to the new online non-commercial service for audio restoration intended to enhance the content of digitized audio repositories. Missing or distorted audio samples are predicted using neural networks and a specific implementation of the Jannsen interpolation method based on the autoregressive model (AR) combined with the iterative restoring of missing signal samples. Since the distortion...
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BEZCZUJNIKOWE STEROWANIE WOLNOOBROTOWYM SILNIKIEM PMSM Z KOMPENSACJĄ MOMENTU ZACZEPOWEGO
PublicationW pracy przedstawiono propozycję rozwiązania problemu bezczujnikowego sterowania wolnoobrotową maszyną synchroniczną z magnesami trwałymi PMSM. Przedstawiono silnik PMSM, który zastosowano w stanowisku badawczym. Omówiono problem występowania tętnień momentu napędowego wynikający głównie ze znacznego momentu zaczepowego. Pokazano rozwiązanie kompensujące tętnienia momentu napędowego w silniku PMSM. Przygotowano procedurę startową...
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Sprawiedliwość agrarna Thomasa Paine’a i narodziny dyskursu egalitarnego
PublicationThomas Paine napisał Sprawiedliwość agrarną we Francji w roku 1796 w szczycie posttermidoriańskiego zamętu, krótko po wprowadzeniu Konstytucji Roku III. W swoim ostatnim wielkim pamflecie domaga się opodatkowania wielkich właścicieli ziemskich i pomoc biednym oraz wywłaszczonym. Artykuł krótko omawia propozycję Paine i analizuje jego strukturę argumentacyjną. Stawiam w niej tezę, że Paine nie do końca świadomie przechodzi od dowodu...
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Tetrahydroquinolinone derivatives exert antiproliferative effect on lung cancer cells through apoptosis induction
PublicationThe anticancer properties of quinolones is a topic of interest among researchers in the scientific world. Because these compounds do not cause side effects, unlike the commonly used cytostatics, they are considered a promising source of new anticancer drugs. In this work, we designed a brief synthetic pathway and obtained a series of novel 8-phenyltetrahydroquinolinone derivatives functionalized with benzyl-type moieties at position...
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A simplified energy dissipation based model of heat transfer for subcooled flow boiling
PublicationIn the paper a model is presented based on energetic considerations for subcooled flow boiling heat transfer. The model is the extension of authors own model developed earlier for saturated flow boiling and condensation. In the former version of the model we used the heat transfer coefficient for the liquid single-phase as a reference level, due to the lack of the appropriate model for heat transfer coefficient for the subcooled...
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Experimental validation of pressure drop models during flow boiling of R134a – effect of flow acceleration and entrainment
PublicationA crucial step to assure proficient work of power and process apparatus is their proper design. A wide array of those devices operates within boiling or condensation of the working fluid to benefit from high heat transfer rates. Two-phase flows are associated with high heat transfer coefficients because of the latent heat of evaporation and high turbulence level between the liquid and the solid surface. Predicting heat transfer...
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Modelling study of flow boiling heat transfer of perspective fluids for refrigeration technology
PublicationThere is a gap of knowledge on flow boiling at high saturation temperatures and higher values of reduced pressure. Thus far, the in-house developed semi-empirical model for flow boiling and flow condensation showed a satisfactory accuracy for calculations for various refrigeration fluids for a wide scope of reduced pressures. This study presents results of calculations of heat transfer coefficient of perspective refrigeration fluids,...
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Large dynamic range high frequency fully differential CMOS transconductanceamplifier.
PublicationW pracy zaproponowano nową koncepcję układową w pełni różnicowego wzmacniacza transkonduktancyjnego CMOS o dużym zakresie dynamiki i szerokim pasmie częstotliwości. Przeprowadzone badania teoretyczne i symulacyjne potwierdziły małe zniekształcenia harmoniczne (THD), szerokie pasmo przenoszonych częstotliwości oraz duży zakres dynamiki dla sygnałów różnicowych.
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Playing CSMA/CA game to deter backoff attacks in ad hoc wireless LANs
PublicationPrzedstawiono wieloetapowe strategie konfiguracji okien rywalizacyjnych w mechanizmie CSMA/CA dla bezprzewodowych sieci lokalnych silnie obciążonych ruchem, zapewniające osiągnięcie doskonałego punktu równowagi Nasha przy konfiguracji standardowej. Wykonano badania symulacyjne dla oceny zbieżności skumulowanych udziałów w pasmie transmisyjnym do wartości w równowadze.
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DESIGN AND THEORETICAL ANALYSIS OF A PROTOTYPE TILTING-PAD RADIAL BEARING WITH ADJUSTABLE CLEARANCE
PublicationThe article introduces a design and analysis results of a prototype ORC (organic Rankine cycle) turbo generator rotor assembly of 300kW power, supported by tilting-pad bearings of original design. The calculations were performed for a prototype turbo generator rotor. The shaft of this machine is supported with two radial bearings, lubricated with an unusual lubricant – a low-boiling-point agent. The main objective of the presented...
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Estimation of Average Speed of Road Vehicles by Sound Intensity Analysis
PublicationConstant monitoring of road traffic is important part of modern smart city systems. The proposed method estimates average speed of road vehicles in the observation period, using a passive acoustic vector sensor. Speed estimation based on sound intensity analysis is a novel approach to the described problem. Sound intensity in two orthogonal axes is measured with a sensor placed alongside the road. Position of the apparent sound...
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Towards Understanding the Health Aspects of the Processing of Lignocellulosic Fillers
PublicationHealth and safety issues should be addressed during the development and investigation of the industrial processes. In order to develop a sustainable process and fully evaluate its benefits and drawbacks for its optimization, it is crucial to determine its impact on the surrounding environment. This study aimed to assess the emission of volatile organic compounds during the modification of lignocellulosic fillers with passive dosimetry....
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Early Oceanographical Data Collected by the Institute of Oceanography, University of Gdańsk
PublicationThree data sets entitled Water currents in Głębinka Passage in late spring of 1975, Hydrometeorological and hydrochemical conditions in the Gulf of Gdańsk in the vicinity of Vistula river mouth in July of 1977, and Gulf of Gdańsk monitoring conducted by the Institute of Oceanography, University of Gdańsk, in 1981–1994 contain archival field measurement results from the Gulf of Gdańsk (the southern Baltic). The data can be used...
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MODELOWANIE MATEMATYCZNE PRZEGRÓD LODOWYCH
PublicationW celu ochrony przed niebezpiecznym zjawiskiem zatoru lodowego opracowano szereg metod, które można podzielić na metody czynne i bierne. Pierwsza grupa obejmuje działania techniczne prowadzące do mechanicznego lub termicznego usuwania lodu i neutralizacji zatorów. Wykorzystuje się w tym calu głównie lodołamacze lub innego typu jednostki pływające. Do metod biernych zalicza się przede wszystkim przegrody lodowe budowane w celu stabilizacji...
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INNOVATIVE THERMODYNAMICAL CYCLES BASED ON ENHANCEMENT MASS, MOMENTUM, ENTROPY AND ELECTRICITY TRANSPORT DUE TO SLIP, MOBILITY, TRANSPIRATION, ENTROPY AND ELECTRIC JUMPS AS WELL AS OTHER NANO-FLOWS PHENOMENA
PublicationIn our work, a further development of the authors model of thermo-chemical flow of fuel, air, oxygen, steam water, species, ionic and electron currents within nano channels and nano-structures of novel devices is presented. Different transport enhancement models are taken into account -among them the most important are: the velocity slip connected with complex external friction, the Darcy mobility and the Reynolds transpiration....
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Unsaturated, biobased polyesters and their cross-linking via radical copolymerization
PublicationBiobased, unsaturated polyesters derived from isosorbide, maleic anhydride and succinic acid were synthesized and characterized. The presence of maleic anhydride units in the structure of the polyesters allowed converting them into cured coatings by radical copolymerization with cross-linking agents such as 2-hydroxyethyl methacrylate, N-vinyl-2-pyrrolidinone, acrylic acid or methacrylamide. The investigated polyesters were obtained...
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Emission of 1.3–10 nm airborne particles from brake materials
PublicationOperation of transport vehicle brakes makes a significant contribution to airborne particulate matter in urban areas, which is subject of numerous studies due to the environmental concerns. We investigated the presence and number fractions of 1.3–10 nm airborne particles emitted from a low-metallic car brake material (LM), a non-asbestos organic car brake material (NAO) and a train brake cast iron against a cast iron. Particles...
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Recent advances in aqueous virus removal technologies
PublicationThe COVID-19 outbreak has triggered a massive research, but still urgent detection and treatment of this virus seems a public concern. The spread of viruses in aqueous environments underlined efficient virus treatment processes as a hot challenge. This review critically and comprehensively enables identifying and classifying advanced biochemical, membrane-based and disinfection processes for effective treatment of virus-contaminated...
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Knowledge economics and the demand for higher education
PublicationThis article suggests that the decreased demand for higher education in Poland is partially caused due to the changes in consumer preferences. The appearance of a cheap and highly accessible form of knowledge offered by the massive open online courses is presumed here to have an effect on the demand for formal higher education. This article proposes an additional perspective to the research on knowledge consumption, especially...
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The Influence of Selected Parameters of Numerical Modelling on Strains and Stresses at Weld Toe Notch
PublicationLatest development in the field of welding technology and prefabrication enabled massive production of thin-walled sandwich structures. Multi-layered sandwich structures are fabricated with the use of high-power CO2 lasers, friction welding, arc welding, hybrid welding, or other technique designed for the special purpose. Steel or aluminium alloy plates with thickness between 1 and 5 mm are connected by internal stiffeners. Strength...
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A Framework of a Ship Domain-based Collision Alert System
PublicationThe paper presents a framework of a planned ship collision alert system. The envisaged system is compliant with IMO Resolution MSC.252 (83) “Adoption of the revised performance standards for Integrated Navigation Systems (INS)”. It is based on a ship domain-oriented approach to collision risk and introduces a policy of alerts on dangerous situations. The alerts will include cautions, warnings and alarms, which will be triggered...
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Educational model of the OFDM modulator and demodulator
PublicationW pracy przedstawiono komputerową implemenację modulatora i demodulatora OFDM. Głównym celem było stworzenie edukacyjnego modelu odbiornika OFDM pracującego w pasmie akustycznym. Omówiono ogólną strukturę modulatora i demodulatora OFDM i zaproponowano oryginalny projekt. Najważniejsze elementu projektu to algorytm synchronizacji symbolowej oraz moduły QMI / QDD przystosowujące surowy sygnał OFDM do kanału pasmowego.
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Damage detection in 3D printed plates using ultrasonic wave propagation supported with weighted root mean square calculation and wavefield curvature imaging
Publication3D printing (additive manufacturing, AM) is a promising approach to producing light and strong structures with many successful applications, e.g., in dentistry and orthopaedics. Many types of filaments differing in mechanical properties can be used to produce 3D printed structures, including polymers, metals or ceramics. Due to the simplicity of the manufacturing process, biodegradable polymers are widely used, e.g., polylactide (polylactide...
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α-Pinene, 3-carene and d-limonene in indoor air of Polish apartments: The impact on air quality and human exposure
PublicationMonoterpenes are among most ubiquitous volatile organic compounds (VOCs) to be detected in indoor air. Since the quality of indoor air is considered important for inhabitants' well-being, the present study aimed at investigating impact of human activity on levels of selected monoterpenes applying passive sampling technique followed by thermal desorption and gas chromatography coupled mass spectrometry. One of the objectives of...