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Wyniki wyszukiwania dla: UNDERWATER COATINGS
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Propulsion System Analysis Based on Particle Image Velocimetry Method in Biomimetic Unmanned Underwater Vehicle
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Study of probe signal bandwidth influence on estimation of coherence bandwidth for underwater acoustic communication channel
PublikacjaA signal transmitted in a shallow Underwater Acoustic Communication (UAC) channel suffers from time dispersion due to the multipath propagation and the refraction phenomena. This causes intersymbol interference of the received signal and frequency-selective fading observed in its spectrum. Coherence bandwidth is one of the key transmission parameters used for designing the physical layer of a data transmission system to minimise...
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Effect of underwater local cavity welding method conditions on diffusible hydrogen content in deposited metal
PublikacjaOne of the methods with great potential for applications in underwater repairs is local cavity welding. In local cavity method, cooling conditions and diffusible hydrogen amount in weld metal are nearly the same as those existed during welding in the air. This paper presents the results of literature survey and preliminary tests of the effect of local cavity welding conditions on diffusible hydrogen amount in a deposited metal....
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Application of unmanned USV surface and AUV underwater maritime platforms for the monitoring of offshore structures at sea
PublikacjaThe operation of offshore structures at sea requires the implementation of advanced systems for their permanent monitoring. There is a set of novel technologies that could be implemented to deliver a higher level of effective and safe operation of these systems. A possible novel solution may be the application of a new maritime unmanned (USV) surface and underwater vehicles/platforms (AUV). Application of such vehicles/platforms...
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A study on fibre-reinforced concrete elements properties based on the case of habitat modules in the underwater sills
PublikacjaHydrotechnical constructions are mostly objects functioning in extreme conditions and requiring a custom-made construction project. In the case of using prefabricated elements, it is required to develop production, transport, assembly, conservation and repair technology. Concerning the problem of concrete cracks, modern repair systems allow positive effects to be achieved in many cases of concrete elements repair. In this work...
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A method for testing the wide-sense stationary uncorrelated scattering assumption fulfillment for an underwater acoustic channel
PublikacjaWide-sense stationary and uncorrelated scattering (WSSUS) assumptions are often applied for the statistical description of wireless communication channels. However, in the case of underwater acoustic channels the WSSUS model is of limited value. The degree of similarity of in-phase and quadrature components of the channel impulse response, measured with the use of bandpass modulated signals, can be used as an indicator of WSSUS...
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3D Object Shape Reconstruction from Underwater Multibeam Data and Over Ground Lidar Scanning
PublikacjaThe technologies of sonar and laser scanning are an efficient and widely used source of spatial information with regards to underwater and over ground environment respectively. The measurement data are usually available in the form of groups of separate points located irregularly in three-dimensional space, known as point clouds. This data model has known disadvantages, therefore in many applications a different form of representation,...
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Simulation of Direct-Sequence Spread Spectrum Data Transmission System for Reliable Underwater Acoustic Communications
PublikacjaUnderwater acoustic communication (UAC) system designers tend to transmit as much information as possible, per unit of time, at as low as possible error rate. It is a particularly difficult task in a shallow underwater channel in which the signal suffers from strong time dispersion due to multipath propagation and refraction phenomena. The direct-sequence spread spectrum technique (DSSS) applied successfully in the latest standards...
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Effect of water salinity on properties of multipass underwater wet manual metal arc welded joints
PublikacjaThe weldability of steel under the water is limited due to the influence of the environment. Water causes limited visibility, presence of the residual stresses, increasing the cooling rate, and increasing the diffusible hydrogen content in deposited metal, leading to the formation of brittle microstructures in heat-affected zone (HAZ). The paper presents the results of mechanical properties testing of S420G2+M steel welded joints...
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The lubricant-coating interaction in rolling and sliding contacts
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Evaluation of coating systems using impedance spectroscopy
PublikacjaTrwałość powłokowych systemów ochronnych zależy od oddziaływań środowiska i związana jest nieodwracalnymi procesami chemicznymi i fizycznymi. Zastosowanie spektroskopii impedancyjnej pozwala na określenie obszaru zastosowań danej powłoki i prognozowanie okresu jej trwałości. W pracy zamieszczono przykłady oceny trwałości systemów powłokowych stosowanych w strategicznych konstrukcjach.
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Hydroxyapatite films as biocompatibile coating for artifical bone
PublikacjaW artykule została szczegółowo opisana budowa kości oraz materiał biokompatybilny hydroksyapatyt (HAp). Autorzy wykazali jak wielkie podobieństwo do budowy kości przejawia sztuczny hydroksyapatyt. opisali syntezy powłoki z HAp.
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Transverse surface waves on a cylindrical surface with coating
PublikacjaWe discuss the propagation of transverse surface waves that are so-called whispering-gallery waves along a surface of an elastic cylinder with coating. The coating is modelled in the framework of linearized Gurtin–Murdoch surface elasticity. Other interpretations of the surface shear modulus are given and relations to so-called stiff interface and stiff skin model are discussed. The dispersion relations are obtained and analyzed.
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Examination of the epoxy coating system's resistance to Corrobill
PublikacjaThe tests of the influence of the surface cleaning agent on the epoxy coating were carried out. Electrochemical and corrosion tests were carried out. The effect of the preparation on the adhesion and hardness of the tested coating was tested.
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Impedance measurements of coating properties on bridge structures
PublikacjaPomiary impedancyjne pozwalają na prostą ocenę właściwości ochronnych powłok ochronnych i wykładzin. Pomiary stosuje się w celu porównania powłok, monitorowania ich właściwości i oceny mechanizmu działania. Metodyka jest z powodzeniem stosowana w pomiarach laboratoryjnych. Pomiary terenowe są bardziej skomplikowane ponieważ wymagają w pełni kontrolowanych komputerowo przyrządów, kontroli warunków pogodowych oraz wielu innych parametrów...
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Hydroacoustic System in a Biomimetic Underwater Vehicle to Avoid Collision with Vessels with Low-Speed Propellers in a Controlled Environment
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Reliable OFDM Data Transmission with Pilot Tones and Error-Correction Coding in Shallow Underwater Acoustic Channel
PublikacjaThe performance of Underwater Acoustic Communication (UAC) systems are strongly related to the specific propagation conditions of the underwater channel. Horizontal, shallow-water channels are characterised by extremely disadvantageous transmission properties, due to strong multipath propagation and refraction phenomena. The paper presents the results of communication tests performed during a shallow, inland-water experiment with...
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Research and development on underwater acoustic systems at Polish Naval Academy and Gdansk University of Technology for the Polish Navy
PublikacjaWe wstępie artykułu wymieniono korzystne aspekty prawie pięćdziesięcioletniej współpracy obu Uczelni z polską Marynarką Wojenną. W dalszych częściach omówiono prace z dziedziny hydroakustyki wykonywane na rzecz Marynarki Wojennej w ciągu ostatnich dziesięciu lat. W Akademii MW w tym okresie były to głównie prace związane z pomiarami i analizami hydroakustycznych pól okrętów wraz z aplikacjami technicznymi tych analiz oraz aplikacje...
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MSIS sonar image segmentation method based on underwater viewshed analysis and high-density seabed model
PublikacjaHigh resolution images of Mechanically Scanned Imaging Sonars can bring detailed representation of underwater area if favorable conditions for acoustic signal to propagate are provided. However to properly asses underwater situation based solely on such data can be challenging for less than proficient interpreter. In this paper we propose a method to enhance interpretative potential of MSIS image by dividing it in to subareas depending...
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Financial system ratings.
PublikacjaW rozdziale tym autor przedstawił wyniki swoich badań nad wykorzystaniem sztucznych sieci neuronowych w prognozowaniu upadłości przedsiębiorstw. Przedstawiono również propozycję klasyfikacji metod analizy dyskryminacyjnej oraz perceptronu wielowarstwowego stosowanych w prognozowaniu zagrożeń upadłością firm. Tabel:2, rysunków:9.
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Fabrication of anti-corrosion nitrogen doped graphene oxide coatings by electrophoretic deposition
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Crystalline hydroxyapatite coatings synthesized under hydrothermal conditions on modified titanium substrates
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Impact of Plasma Pre-Treatment on the Tribological Properties of DLC Coatings on PDMS Substrates
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Use of impedance spectroscopy to evaluate the durability of protective coatings after thermal shock
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Electrochemical investigations of conductive coatings applied as anodes in cathodic protection of reinforced concrete
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Mechanical and Corrosion Properties of Laser Surface-Treated Ti13Nb13Zr Alloy with MWCNTs Coatings
Publikacja: Titanium and its alloys is the main group of materials used in prosthetics and implantology. Despite their popularity and many advantages associated with their biocompatibility, these materials have a few significant disadvantages. These include low biologic activity—which reduces the growth of fibrous tissue and allows loosening of the prosthesis—the possibility of metallosis and related inflammation or other allergic reactions,...
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Microstructure and mechanical properties of laser surface-treated Ti13nb13zr alloy with MWCNTs coatings
PublikacjaLaser surface modification of titanium alloys is one of the main methods of improving the properties of titanium alloys used in implantology. This study investigates the microstructural morphology of a laser-modified surface layer on a Ti13Nb13Zr alloy with and without a carbon nanotube coating deposited by electrophoretic deposition. Laser modification was performed for samples with and without carbon nanotube coating for two...
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Electrophoretic Deposition and Characteristics of Chitosan–Nanosilver Composite Coatings on a Nanotubular TiO2 Layer
PublikacjaThe surface treatment of titanium implants has been applied mainly to increase surface bioactivity and, more recently, to introduce antibacterial properties. To this end, composite coatings have been investigated, particularly those based on hydroxyapatite. The present research was aimed at the development of another coating type, chitosan–nanosilver, deposited on a Ti13Zr13Nb alloy. The research comprised characterization of the...
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PARAMETERS OF THE ELECTROPHORETIC DEPOSITION PROCESS AND ITS INFLUENCE ON THE MORPHOLOGY OF HYDROXYAPATITE COATINGS. REVIEW
PublikacjaMetallic materials intended for bone implants should exhibit not only appropriate mechanical properties, but also high biocompatibility. The surface treatment modifications, for example acidic treatment, laser treatment, ion implantation and deposition of highly biocompatible coatings, are practiced. One of the most popular methods of surface modification is to deposit hydroxyapatite (HAp) coatings. HAp naturally occurs in human...
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Electrophoretic Deposition and Characterization of Chitosan/Eudragit E 100 Coatings on Titanium Substrate
PublikacjaCurrently, a significant problem is the production of coatings for titanium implants, which will be characterized by mechanical properties comparable to those of a human bone, high corrosion resistance, and low degradation rate in the body fluids. This paper aims to describe the properties of novel chitosan/Eudragit E 100 (chit/EE100) coatings deposited on titanium grade 2 substrate by the electrophoretic technique (EPD). The deposition...
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Mechanical Properties and Sliding Wear Resistance of Suspension Plasma Sprayed YSZ Coatings
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Properties of nano-Fe3O4 incorporated epoxy coatings from Cure Index perspective
PublikacjaThe mission of an advanced epoxy-based nanocomposite coating is to provide a given substrate with protection against an unwelcome guest; e.g. corrosive molecules/media, environmental stress, flame, thermal degradation or microorganisms. In such systems, the degree to which superior properties can be guaranteed depends on the state of network formation in the epoxy in the presence of nanoparticles. For low-filled epoxy nanocomposite coatings,...
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Fabrication of anti-corrosion nitrogen doped graphene oxide coatings by electrophoretic deposition
PublikacjaThis work assesses anti-corrosion properties of graphene and N-doped graphene coatings deposited on copper by an electrophoretic method. Graphene oxide (GO) precursor was synthesized by an improved Hummers' method, whereas N-doping was performed hydrothermally in the presence of ammonia. After nitrogenation, doped graphene oxide samples (NGO) contained a reduced amount of oxygen and about 9% w/w nitrogen as pyridinic, pyrrole,...
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Electrochemical investigations of conductive coatings applied as anodes in cathodic protection of reinforced concrete.
PublikacjaW pracy przedstawiono rezultaty badań elektrochemicznych polimerów przewodzących z pigmentem grafitowym. Wyznaczono parametry elektrochemiczne badanych powłok w trakcie długotrwałej polaryzacji zbrojonego betonu. W oparciu o pomiary impedancyjne wyznaczono parametry elektrochemiczne powłok przewodzących. Wykazano, że badane powłoki mogą być stosowane w ochronie katodowej żelbetu. Badania wykazały, że optymalne stężenie grafitu...
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Time domain diagnosis of anticorrosion coatings via shape designed measurement signals.
PublikacjaW pracy przedstawiono operującą w dziedzinie czasu metodę diagnostyki pokryć przeciwkorozyjnych, na poziomie identyfikacji parametrów obwodu zastępczego. Metoda jest oparta na pobudzeniu obiektu sygnałem niekonwencjonalnym o projektowanym kształcie i pomiarze odpowiedzi obiektu (tzw. obserwabla) po upływie zadanego czasu T. Parametry obwodu zastępczego są obliczane bezpośrednio z obserwabli na podstawie równań wynikających z topologii...
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Developing electrochemical measurements in order to assess anti-corrosive coatings more effectively
PublikacjaCelem pracy było sprawdzenie powtarzalności wyników uzyskanych metodą pomiaru szumu (Electrochemical Noise method - ENM) elektrochemicznego wykonanych na powłokach organicznych w konfiguracji bez połączenia z podłożem metalowym (NOCS - No Connection to the Substrate). NOCS polega na wykonaniu pomiarów na trzech teoretycznie takich samych obszarach badanego układu. W takim układzie nie jest wymagane połączenie elektryczne z metalowym...
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A Multi Rig Screening Test for Thin Ceramic Coatings in Bio-Tribological Applications
PublikacjaZaprezentowano metodę badań ogólnej charakterystyki tribologicznej cienkich powłok ceramicznych z wykorzystaniem równoległych testów na wielu stanowiskach o różnej konfiguracji styku powierzchni trących i przy ruchu o różnym charakterze (jednokierunkowym i posuwisto zwrotnym). Przedstawiono wyniki porównania przy pomocy jednoczesnej analizy wyników testów z różnych stanowisk; w wyniku testów uzyskano ranking powłok ze wskazaniem...
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Method using square-pulse excitation for high-impedance spectroscopy of anticorrosion coatings
PublikacjaArtykuł prezentuje metodę spektroskopii impedancyjnej przeznaczonej do diagnostyki powłok antykorozyjnych na obiektach bezpośrednio w terenie. Aby skrócić czas uzyskania widma impedancji (w zakresie od 1 mHz do 1 MHz) do kilku minut, wykorzystano sygnały harmoniczne do pomiaru widma powyżej 10 Hz a impuls prostokątny w dolnym zakresie częstotliwości. Do wyznaczania widma użyto algorytmów DSP odpowiednich do sygnału pobudzenia....
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Influence of silver nanoparticles addition on antibacterial properties of PEO coatings formed on magnesium
PublikacjaMagnesium is a biodegradable material and thus could be a choice for bone fixation devices and implants with a specific purpose. This study aims to enhance the anti-corrosive, biocompatible, and antibacterial properties on magnesium-based materials through ceramic coatings formation. To achieve this the silicate-based electrolyte was used to create of Plasma Electrolytic Oxidation (PEO) coatings. During investigation the bioactive...
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Cavitation erosion of chromium-manganese and chromium-cobalt coatings processed by laser beam
PublikacjaPrzedstawiono wyniki badań erozji kawitacyjnej napoin wykonanych za pomocą elektrod chromowo-manganowych i chromowo-niklowych oraz obrobionych wiązką lasera CO2 o mocy 1000 W. Próbki poddawano obciążeniom kawitacyjnym na stanowisku z wirującą tarczą. Zaobserwowano wzrost odporności kawitacyjnej napoin, w których dokonano przetopienia ich powierzchni promieniowaniem lasera.
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Properties of Nanohydroxyapatite Coatings Doped with Nanocopper, Obtained by Electrophoretic Deposition on Ti13Zr13Nb Alloy
PublikacjaNowadays, hydroxyapatite coatings are the most common surface modification of long-term implants. These coatings are characterized by high thickness and poor adhesion to the metallic substrate. The present research is aimed at characterizing the properties of nanohydroxyapatite (nanoHAp) with the addition of copper nanoparticle (nanoCu) coatings deposited on the Ti13Zr13Nb alloy by an electrophoresis process. The deposition of...
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Polyurethane/Silane-Functionalized ZrO2 Nanocomposite Powder Coatings: Thermal Degradation Kinetics
PublikacjaA polyurethane (PU)-based powder coating reinforced with vinyltrimethoxysilane (VTMS)-functionalized ZrO2 nanoparticles (V-ZrO2) for thermal stability was developed. Chemical structure, microstructure and thermal degradation kinetics of the prepared coatings were investigated. The peak of aliphatic C–H vibrating bond in the Fourier transform infrared (FTIR) spectrum of V-ZrO2 was a signature of VTMS attachment. Scanning electron...
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Towards high quality ITO coatings: the impact of nitrogen admixture in HiPIMS discharges
PublikacjaThe paper reports controlled deposition of optically transparent and electrically conductive ITO films prepared by a combination of rf (13.56 MHz) and High Power Impulse Magnetron Sputtering (HiPIMS) systems without any post deposition thermal treatment/annealing. It is shown that (i) reactive admixture of N2 gas to the process and (ii) pressure in the deposition chamber enable to optimize optical properties of ITO films. Furthermore,...
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Structural and mechanical properties of hydroxyapatite coatings formed by ion-beam assisted deposition
PublikacjaThe ion-beam assisted deposition (IBAD) is an advanced method capable of producing crystalline coatings at low temperatures. We determined the characteristics of hydroxyapatite Ca10(PO4)6(OH)2 target and coatings formed by IBAD using X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray (EDX). The composition of the coatings'...
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A Multi Rig Screening Test for Thin Ceramic Coatings in Bio - Tribological Applications
PublikacjaA method is presented for the comparative testing of wear resistance of ceramic coatings made from materials potentially feasible in tribo - medical applications, mainly orthopaedic implants made from ceramics coated metals for low cost, long life and low wear particle emission into the body. The method was devised as the main tool for use in research and is comprised of flat on flat and ball on flat surface (sliding) tests. Seven...
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Experimental review of the performances of protective coatings for interconnects in solid oxide fuel cells
PublikacjaFerritic stainless steel interconnects are used in solid oxide fuel cells; however, coatings are required to improve their performance. Although several types of coatings have been proposed, they have been scarcely investigated under similar conditions. This study compares the characteristics of uncoated Crofer 22 APU and eight different coatings on Crofer 22 APU for up to 3000 h at 800 ◦C. The coatings were deposited at various...
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Test loadings of arch bridges
PublikacjaIn Poland an appreciable developement of bridge building can be seen in recent years. Arch structures are more and more common, because of the original geometrical and aesthetical form, aside with explicit structural system. Paper concerns the applied computational conceptions and researches on an example of two arch bridges. The goal of the studies is to check the correctness of the real construction work and design assumptions,...
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Accelerated ageing of organic coating systems by thermal treatment
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Special Issue “Corrosion Resistance of Alloy and Coating Materials”
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Temperature Fiber-Optic Sensor with ZnO ALD Coating
PublikacjaThis study presents a microsphere-based fiber-optic sensor with a ZnO Atomic Layer Deposition (ALD) coating thickness of 100 nm for temperature measurements. Metrological properties of the sensor were investigated over the temperature range of 100 °C to 300 °C, with a 10 °C step. An interferometric signal is used to control whether the microstructure is whole. Spectrum shift of a reflected signal is used to ascertain changes in...