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Search results for: DEGRADATION CAVITATION
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Thermal degradation of copolymers based on selected alkyl methacrylates
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Photocatalytic degradation using nitrogen-modified titanium dioxide
PublicationPrzepływowy reaktor z wypełnieniem został zastosowany do przeprowadzenia fotodegradacji 4-chlorofenolu za pomocą światła widzialnego. Fotokatalizator w postaci tlenku tytanu(IV) modyfikowanego azotem, został naniesiony na powierzchnię kulek szklanych. Źródło światła widzialnego stanowiła 8W lampa fluorescencyjna. Powietrze było w sposób ciągły przepuszczane przez zawartość reaktora.
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Pathways and analytical tools in degradation studies of organic pollutants
PublicationWszystkie substancje chemiczne podlegają różnym procesom w wyniku wielu reakcji chemicznych, biochemicznych czy też fotochemicznych. W zależności od elementu środowiska w jakim znajduje się analit (np.: gleba, sedymenty, wody powierzchniowe i podziemne), może on ulegać powolnym przemianom w wyniku różnych procesów. W pracy przedstawiono niektóre drogi degradacji wybranych substancji w różnych warunkach. Omówiono problem identyfikacji...
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Hydrogen degradation of high strength low alloyed steels.
PublicationBadano wpływ polaryzacji katodowej na własności stali węglowej, stali o podwyższonej i wysokiej wytrzymałości metodą stałego powolnego odkształcania.Stwierdzono, że stopień kruchości wodorowej każdej z badanych stali zależał od stężenia wodoru dyfuzyjnego.
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Degradation of ferritic X10CrAlSi18 stainless steel caused by slurry
PublicationThe slurry erosion tests of ferritic X10CrAlSi18 steel were carried out using a slurry pot device. In order to investigate the erosion process, two series of tests were performed: first one with a constant impact velocity of 5 m/s, 7 m/s and 9 m/s and the second one, during which the impact velocity was changed after every exposure. During each test, an influence of test conditions on volume loss, surface hardness and roughness...
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Peroxymonosulfate-assisted photocatalytic degradation of artificial sweeteners in water
PublicationIn the present study, peroxymonosulfate (PMS) activation was proposed for efficient photocatalytic degradation of aspartame, acesulfame, saccharin, and cyclamate - artificial sweeteners frequently present in wastewaters and surface waters worldwide. The TiO2 nanosheets with exposed {0 0 1} facets were synthesised using the fluorine-free lyophilisation technique as a green concept for the synthesis and used for the photodegradation...
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Hydrogen degradation of high-strength weldable steels in seawater
PublicationOceniono podatność na niszczenie wodorowe stali spawalnych o wysokiej wytrzymałości przy obciążeniach monotonicznie rosnących. Badano dwa gatunki stali ulepszonych cieplnie i ich złącza spawane. Przeprowadzono próby rozciągania z małą prędkością odkształcania w wodzie morskiej przy polaryzacji katodowej. Wykonano próby przenikania wodoru metodą Devanathana-Stachurskiego.
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Corrosion degradation impact on mechanical properties of structural steel
PublicationRecently, extensive research was conducted regarding the impact of corrosion degradation on the mechanical properties of structural steel. Studies show that at the material level, the microstructure is somewhat unchanged due to corrosion degradation. However, the corrosion causes pits and structural surface irregularities that consequently impact the mean stress-strain response of typical coupon specimens subjected to tensile loading....
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The influence of the UV irradiation on degradation of virgin rapeseed oils
PublicationThis paper presents research which is a continuation of the investigations described earlier. The aim of these studies was to determine the influence of UV irradiation on flavor and the oxidative stability of different rapeseed oils varieties. For the purpose of this study, oil samples underwent accelerated deterioration for 4.5 h under a UV light test. In the obtained sample, characteristic values (peroxide (PV, 1.23–1.62 meq...
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Approach to evaluation of time to the critical degradation of ship pipelines
PublicationIn the article an approach to the problem of estimating time to the critical degradation of ship pipelines is considered. Such an assessment would consist of six stages. The fundamental idea is to include to the estimation of time to failure of pipelines such elements like: materials that the pipelines are made, destructive physical phenomena taking place in them and applied means of protection. The result of that evaluation should...
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Degradation kinetics and mechanism of pentoxifylline by ultraviolet activated peroxydisulfate
PublicationDegradation of pentoxifylline (PTX) by sodium peroxydisulfate (SPDS) assisted by UV irradiation has been investigated in deionized water. The treatment was more favorable over direct photolysis or peroxydisulfate oxidation alone. The effects of various parameters, including different dosage of oxidant agent, PTX concentration, initial solution pH levels, and the presence of inorganic ions like chloride, nitrate and carbonate have...
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The impact of material degradation on the resistance and reliability of truss structures
PublicationThe paper analyses limit load-carrying capacity and buckling load of truss towers used to support high voltage power lines. The analysed typical structure was subjected to characteristic loads and their combinations. The results were applied to assess structural resistance with regard to steel corrosion in the long-term operation. The extent of structural deterioration was assessed due to Young's modulus decrement in the course...
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Photocatalytical degradation of toluene and cyclohexane using LED illumination
PublicationA sol-gel process followed by hydrothermal reaction was used to prepare coupled WO3-TiO2 photocatalysts with varying amounts of WO3 in respect to TiO2 (3 mol% and 5 mol% respectively). Additionally, photocatalysts have been subjected to different calcination temperatures of 400ºC and 800ºC, which allowed us to compare how these affect photodegradation efficiency. Photocatalysts were characterized under a scanning electron microscope,...
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Modelling processes for Polish civil aviation market
PublicationThe present , paper is the first step in research of Polish civil aviation market, focusing on the area of civil, legacy airlines. First, the market is described with its players, current conditions and its main problems. Next, the tools which are currently used for the prognosis processes are presented. Finally, the idea of a new model (fuzzy model) for the process of prognosis is presented.
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THE CASE OF MANAGEMENT CONCEPTS IN CIVIL AVIATION BUSINESS.
PublicationThe article presents the changes in management concepts used in civil aviation business in last 25 years. There is a need to make prognosis and support decision-making processes with different models but each model is adapted to current management concept. This article will present the changes and possible future trends in management concepts with the description of strengths and weaknesses of each of them. These might be used...
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A study of cavitation erosion resistance of an ion nitrided titanium alloy by means of the vibration and rotating disk methods
PublicationIn this work, a comparative analysis of the cavitation erosion resistance of the Ti– 6.7Al–2.5Mo–1.8Cr–0.5Fe–0.25Si alloy (known as brand VT3-1) before and after lowtemperature ion nitriding is carried out. Two test methods were applied, using vibrative (ASTM G-32) and rotating disk rigs, respectively. The kinetic dependences of the erosive destruction of samples of titanium alloy VT3-1 in the initial state, after ion nitriding...
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Magnetic properties of BiFeO3micro-cubes synthesized by microwave agitation
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Enhanced degradation of glucocorticoids, a potential COVID-19 remedy, by co-fermentation of waste activated sludge and animal manure: The role of manure type and degradation mechanism
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A History of Maritime Radio-Navigation Positioning Systems used in Poland
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Optimization Model to Manage Ship Fuel Consumption and Navigation Time
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Mobile navigation system for visually impaired users in the urban environment
PublicationThis paper describes the prototype version of a mobile application supporting independent movement of theblind. Its objective is to improve the quality of life of visually impaired people, providing them with navigationalassistance in urban areas. The authors present the most important modules of the application. The module forprecise positioning using DGPS data from the ASG-EUPOS network as well as enhancements of positioning...
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Modeling 3D Objects for Navigation Purposes Using Laser Scanning
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A framework for risk matrix design: A case of MASS navigation risk
PublicationRisk matrix, a tool for visualizing risk assessment results, is essential to facilitate the risk communication and risk management in risk-based decision-making processes related to new and unexplored socio-technical systems. The use of an appropriate risk matrix is discussed in the literature, but it is overlooked for emerging technologies such as Maritime Autonomous Surface Ships (MASS). In this study, a comprehensive framework...
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The Concept of Using the Decision-Robustness Function in Integrated Navigation Systems
PublicationThe diversity and non-uniformity of the positioning systems available in maritime navigation systems often impede the watchkeeping officer in the selection of the appropriate positioning system, in particular, in restricted basins. Thus, it is necessary to introduce a mathematical apparatus to suggest, in an automated manner, which of the available systems should be used at the given moment of a sea trip. Proper selection of the...
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Integration of inertial sensors and GPS system data for underwater navigation
PublicationThe Inertial Navigation System (INS) is usually employed to determine the position of an underwater vehicles, like Remotely Operated Vehicles (ROV) and, more recently, Autonomous Underwater Vehicle (AUV). The accuracy of the position provided by the INS, which uses accelerometers and gyroscopes, deteriorates with time. An external aiding sources such as the Global Positioning System (GPS) can be employed to reduce the error growth...
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Using River Formation Dynamics Algorithm in Mobile Robot Navigation
PublicationRiver Formation Dynamics is a heuristic optimization algorithm based on the manner, in which drops of water form the river bed. The idea is to imitate the movement of drops on the edges between given nodes thus performing a search based on their height, which is modified through the mechanism of soil erosion and sediment deposition. In this way decreasing gradients are constructed, and these are followed by subsequent drops to...
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Non-Satellite Broadband Maritime Communications for e-Navigation Services
PublicationThe development of broadband network access technologies available to users on land has triggered a rapid expansion of a diverse range of services provided by terrestrial networks. However, due to limitations of digital communication technologies in the off-shore area, the maritime ICT systems evolution so far has not followed that trend. Despite the e-navigation initiative defining the set of Maritime Services, the progress in...
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Research and Analysis of Accuracy of Location Estimation in Inertial Navigation System
PublicationIn the article the research and analysis of digital signal processing and its influence on accuracy of location estimation in developed inertial navigation system was presented. The purpose of the system is to localize moving people in indoor environment. During research a measuring unit for recording selected movement parameters was made. In the article were also described author’s inertial navigation algorithms.
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Underwater Navigation System Based on Doppler Shifts of a Continuous Wave
PublicationThe paper describes a concept of an underwater navigation system designed to determine the location and speed of its ROVs or divers. Conducted by the Department of Marine Electronic Systems at the Gdansk University of Technology for several years, research has focused on navigation systems which determine positions on the basis of Doppler shifts of echo signals reflected from a moving object. This article presents a different version...
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UAV Design and Construction for Real Time Photogrammetry and Visual Navigation
PublicationA unmanned aerial vehicles applications in photogrammetry have increased rapidly last years. A fast data gathering and processing in real time in some cases become crucial and desired in some application. In the paper, a real time solution is proposed. A real time photogrammetry from UAV is proposed, where image data are gathered and processed on board UAV and finally reconstructed 3D model and measurements are delivered. The paper...
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Solar Photocatalytic Degradation of Sulfamethoxazole by TiO2 Modified with Noble Metals
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Photocatalytic activity of layered MoS2 in the reductive degradation of bromophenol blue
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Spectroscopic investigations into degradation of polymer membranes for fuel cells applications
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Immobilized TiO2for Phenol Degradation in a Pilot-Scale Photocatalytic Reactor
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DEGRADATION OF GFRP MARINE LAMINATES WITH NANO PARTICLE MODIFIED COATINGS
PublicationWater absorption and surface blistering behaviour was studied for polyester-matrix laminates with SiO2 nanoparticle reinforced gel coats. Accelerated water immersion tests at 37°C showed that addition of 10% nanoparticles increases blisters incubation time by ca. 50% compared to 5% and 0% nanoparticles composites.
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Environmental degradation of Ti alloys in artificial saliva and a role of fluorides
PublicationThe titanium and its alloys are potentially prone to hydrogen embrittlement, including those proposed for dental implants. The research has been aimed to assess a susceptibility to environment-enhanced degradation of the Ti-13Zr-13Nb alloy in artificial saliva with or without hydrofluoric acid, subject or not to cathodic polarisation. The results have shown that even if artificial saliva is safe environment, both cathodic polarization...
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Study of excitation energy transport and degradation in aqueous solution of FMN
PublicationStudy of excitation energy transport and degradation in aqueous solution of FMN
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Evaluation of reformer tubes degradation after long term operation
PublicationPurpose of this paper is to show the effect of long-term service at elevated temperatures on microstructural changes of cast steel reformer tubes made of the alloy IN-519 (24%Cr, 24%Ni, Nb). The relationship between mechanical properties and microstructure degradation is discussed. Investigations were performed on five tubes taken from ammonia reformer furnace. Tubes worked at temperature of 880C and 3,2 MPa pressure. The operation...
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Degradation of polycaprolactone modified with TPS or CaCO3 in biotic/abiotic seawater
PublicationThis paper is an investigation of the polymer degradation process in two types of seawater (with and without microorganisms) sourced from the Baltic Sea. The chosen polymeric materials were polycaprolactone modified with either thermoplastic starch (PCL/TPS>85%) or calcium carbonate (60% PCL/40% CaCO3) compared directly against unmodified polycaprolactone. All samples were incubated for 28 weeks in seawater with and without microorganisms...
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Identification and localization of organic coating degradation onset by impedance imaging
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Assessment of organic coating degradation via local impedance imaging
PublicationThe paper presents a new approach to organic coating condition evaluation at micrometer scale using localized impedance measurements. It is based on atomic force microscopy (AFM) in contact mode. Impedance is measured between conductive AFM tip and metal substrate covered with organic coating. A single-frequency voltage perturbation signal is applied between the electrodes and current response signal is registered. As the tip is...
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The influence of polypropylene degradation on the membrane wettability during membrane distillation
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Hydrogen degradation of 26H2MF and 34HNM steels used in ship engines.
PublicationPrzedstawiono wyniki badań podatności stali 26H2MF i 34HNM na niszczenie wodorowe, uzyskane po badaniach w roztworze kwasu siarkowego przy równoczesnej polaryzacji katodowej. Wykazano, że skład i obróbka cieplna stali mają wpływ na ich podatność. Efejkt ten przypisano różnej zdolności pułapkowania wodoru przez stale.
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Hydrogen degradation of high-strength weldable steels in sea-water.
PublicationW pracy przedstawiono ocenę degradacji wodorowej dwóch gatunków stali spawalnych o wysokiej wytrzymałości 17HMBVA i 14HNMBCu. Badania wykonano na materiałach rodzimych i złączach spawanych stali w oparciu o próbę rozciągania z małą prędkością. Próby wykonano w powietrzu oraz środowisku wody morskiej przy polaryzacji katodowej. Dodatkowo wykonano elektrochemiczne badania przenikania wodoru i wyznaczono zależności stężenia wodoru...
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Hydrogen degradation of high-strength weldable steels in sea-water
PublicationW artykule przedstawiono ocenę podatności stali o wysokiej wytrzymałości oraz ich złączy spawanych na kruchość wodorową. Wykonano próby powolnego rozciągania na stalach gatunku 17HMBVA i 14HNMBCu oraz ich złączach spawanych, w środowisku wody morskiej, przy polaryzacji katodowej. Wykonano badania elektrochemiczne przenikania wodoru przez membrany pobrane z rożnych obszarów złączy spawanych.
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Degradation of organic coatings subjected to alternating mechanical stress impact.
PublicationW pracy przedstawiono wyniki badań nad wpływem cyklicznych naprężeń mechanicznych na dwa rodzaje systemów powłokowych stosowanych do ochrony konstrukcji mostowych. Powłoki epoksydowe i winylowe poddano cyklom zginanie/odpuszczenie w granicach odkształceń elastycznych materiału podłoża. Stan powłok oceniano przy użyciu techniki elektrochemicznej spektroskopii impedancyjnej. Otrzymane wyniki porównano z zachowaniem analogicznych...
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Hydrogen degradation of the 26H2MF alloy steel in H2SO4 and hydrocarbon environments.
PublicationSTAL 26H2MF ZOSTALA PODDANA RÓZNEJ OBRÓBCE CIEPLNEJ, PO KTÓREJ UZYSKAŁA ONA RÓŻNĄ MIKROSTRUKTURĘ ORAZ CHARAKTER PRZEŁOMU. WYKONANO PRÓBY POWOLNEGO ODKSZTAŁCANIA W ROZCIEŃCZONYM KWASIE SIARKOWYM, PALIWIE CIĘZKIM I PRZEPRACOWANYM OLEJU SILNIKOWYM PRZEPRACOWANYM.
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High-performance activation of ozone by sonocavitation for BTEX degradation in water
PublicationThis work presents a novel advanced oxidation process (AOP) for degradation of emerging organic pollutants – benzene, toluene, ethylbenzene and xylenes (BTEXs) in water. A comparative study was performed for sonocavitation assisted ozonation under 40–120 kHz and 80–200 kHz dual frequency ultrasounds (DFUS). Based on the obtained results, the combination of 40–120 kHz i.e., low-frequency US (LFDUS) with O3 exhibited excellent oxidation...
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Accelerated degradation of organic coatings due to cyclic mechanical stress
PublicationPotrzeba okresowej renowacji wymalowań na obiektach technicznych wynika z naturalnej degradacji powłok ochronnych wskutek oddziaływania czynników obecnych w miejscu eksploatacji. W niniejszej pracy opisano synergiczny wpływ dwóch z nich - promieniowana ultrafioletowego i cyklicznych naprężeń mechanicznych - na trwałość komercyjnie stosowanego zestawu powłokowego przeznaczonego do ochrony konstrukcji mostowych.
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Visible light-enhanced degradation of phenol in the presence of modified TiO2
PublicationOpracowano metody otrzymywania katalizatora na bazie tlenku tytanu (IV) aktywowanego światłem widzialnym do fotokatalitycznego utleniania zanieczyszczeń. Tlenek tytanu (IV) modyfikowano wybranymi organicznymi i nieorganicznymi domieszkami. Aktywność fotokatalityczną otrzymanych próbek katalizatorów zbadano w reakcji degradacji fenolu (co= 0,21 mmol/dm3) w roztworze wodnym, w obecności światła widzialnego (l>400). Wybrane katalizatory...