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Wyniki wyszukiwania dla: arc strikes, underwater welding, smaw, covered electrode, high strength steel, diffusible hydrogen
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Technology of braze welding absorber tubes to copper foil in solar collectors by the GTA method
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Probe signal processing for channel estimation in underwater acoustic communication system
PublikacjaUnderwater acoustic communication channels are characterized by a large variety of propagation conditions. Designing a reliable communication system requires knowledge of the transmission parameters of the channel, namely multipath delay spread, Doppler spread, coherence time, and coherence bandwidth. However, the possibilities of its estimation in a realtime underwater communication system are limited, mainly due to the computational...
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Odporność kawitacyjna grubych powłok ochronnych CrC nanoszonych metodą niskociśnieniowego wyładowania łukowego (Arc-PVD)
PublikacjaReferat przedstawia analizę i metodę pokrywania powierzchni materiałów zastosowanych w turbinach parowych i śrubach okrętowych za pomocą CrC przy zastosowaniu metodę ARC-PVD. Celem jest podwyższenie trwałości powierzchni narażających na erozję wywołaną przez kawitację.
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Autonomous Control of the Underwater Remotely Operated Vehicle in Collision Situation with Stationary Obstacle
PublikacjaThe article considers the problem of autonomous control of the underwater remotely operated vehicle mini Remotely Operated Vehicle (ROV) in a collision situation with a stationary obstacle. The control of the collision avoidance process is presented as a synthesis of fuzzy proportional-differential controllers for the control of distance and orientation concerning the detected stationary obstacle. The control of the submergence...
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Perspective of High Energy Heating Implementation for Steel Surface Saturation with Carbon
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Influence of sulphur on high temperature degradation of steel structures in the refinery industry
PublikacjaArtykuł stanowi przegląd skutków wpływu związków siarki, znajdujących się w mediach procesowych instalacji rafineryjnych, na elementy konstrukcji ze stali węglowych i stopowych. Wyróżniono dwa aspekty wysokotemperaturowej korozji siarkowej: związany z tworzeniem się zgorzeliny siarczkowej i ubytkami masy oraz dotyczący wewnętrznej degradacji elementu w wyniku zmian mikrostruktury stali. Przedstawiono tzw. zmodyfikowane krzywe McConomy...
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Surface roughness analysis of hardened steel after high‐speed milling
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Discrete measurement of fault-arc velocity
PublikacjaOpisano metodę dyskretnego pomiaru prędkości jednofazowego łuku awaryjnego poruszającego się w płaskim, poziomym układzie szyn. Badania przeprowadzono za pomocą punktowych czujników optycznych rozmieszczonych równomiernie wzdłuż szyn. Podano opis układu, jego charakterystykę, wpływ obszaru zjonizowanego na uzyskiwane wyniki i zależności między obserwowanymi wielkościami.
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Short-fuse arc in the magnetic field
PublikacjaDo wymuszenia przerzutu prądu z bezpiecznika krótkotopikowego o dużym prądzie znamionowym, lecz małej zdolności wyłączania do do innego - o małym prądzie znamionowym, lecz dużej zdolności wyłączania konieczne jest wytworzenie przez bezpiecznik krótkotopikowy wysokiego napięcia łukowego. Do tego celu bezpiecznik z topikiem o długości 1 mm wyposażono w rożki łukowe i płykową komorę dejonizacyjną oraz zastosowano zewnętrzne pole...
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Instantaneous Impedance Analysis of Non-Stationary Corrosion Process: a Case Study of Carbon Steel in 1M HCl
PublikacjaThe paper concerns the problem of evaluation of stationarity of carbon steel corrosion in 1M HCl. Comparison of corrosion rate with addition of corrosion inhibitor to the reference measurement is the most often used way of evaluating inhibitor efficiency. Such an approach is valid only if corrosion rate is a stationary process. Two complementary techniques were used simultaneously: volumetric analysis of evolved hydrogen and instantaneous...
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Seafloor Characterisation Using Underwater Acoustic Devices
PublikacjaThe problem of seafloor characterisation is important in the context of management as well as investigation and protection of the marine environment. In the first part of the paper, a review of underwater acoustic technology and methodology used in seafloor characterisation is presented. It consists of the techniques based on the use of singlebeam echosounders and seismic sources, along with those developed for the use of sidescan...
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Robust Model Predictive Control for Autonomous Underwater Vehicle–Manipulator System with Fuzzy Compensator
PublikacjaThis paper proposes an improved Model Predictive Control (MPC) approach including a fuzzy compensator in order totrack desired trajectories of autonomous Underwater Vehicle Manipulator Systems (UVMS). The tracking performancecan be affected by robot dynamical model uncertainties and applied external disturbances. Nevertheless, the MPCas a known proficient nonlinear control approach should be improved by the...
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Hydrogen evolution reaction catalyzed by Co-based metal-organic frameworks and their derivatives
PublikacjaIn this study, Co-bearing Metal-Organic Frameworks (MOFs) are grown via a facile solvothermal process on the surface of two kinds of conductive substrates – titanium dioxide nanotubes (TiO2NT) and fluorine-doped tin oxide (FTO) glass and tested as electrodes in the electrochemical hydrogen evolution reaction (HER). The materials derived from three organic linkers - terephthalic acid (Co-BDC), 2-aminoterephthalic acid (Co-BDCNH2),...
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Investigations on strength and fracture in RC beams scaled along height or length
PublikacjaThe objective of the present paper is to identify experimentally and theoretically differing failure mechanisms in reinforced concrete beams subjected to four-point bending for a separate variation of the depth and length at the constant thickness. Experiments were performed on reinforced concrete beams under four-point bending. Different failure mechanisms included steel yielding, diagonal tension or shear- compression depending...
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THE EFFECT OF NOTCH DEPTH ON CTOD VALUES IN FRACTURE TESTS OF STRUCTURAL STEEL ELEMENTS
PublikacjaIn elements of steel structures working at low temperatures, there is a risk of appearance of brittle fracture. This risk is reduced through the use of certified materials having guaranteed strength at a given temperature. A method which is most frequently used to determine brittle fracture toughness is the Charpy impact test, preformed for a given temperature. For offshore structures intended to work in the arctic climat e, the...
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Corrosion of AISI1018 and AISI304 steel exposed to sulfates
PublikacjaThis research analyses the behavior of corrosion, durability, and quality of reinforced concrete samples coated with two different materials when exposed to contaminated soil with sulfates. The initial assessment involved evaluating the water absorption rate of the coating materials before and after exposure to a solution containing 3%푁푎2푆푂4+3%푀푔푆푂4+3%퐾2푆푂4+3%퐶푎푆푂4to determine their durability. the corrosion...
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UNDERWATER NOISE GENERATED BY A SMALL SHIP IN THE SHALLOW SEA
PublikacjaStudy of the sea noise has been a subject of interest for years. The first work of this scope were published at the turn of the twentieth century by Knudsen (KNUDSEN et al., 1948) and G. Wenz (WENZ, 1962). Disturbances called "shipping noise" are one of the important components of the sea noise. In this work the results of an experimental research of underwater noise produced by a small ship of a classic propulsion are...
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Verification of selected calculation methods regarding shear strength in beams without web reinforcement
PublikacjaThe purpose of the article was to compare selected calculation methods regarding shear strength in reinforced concrete beams without web reinforcement. Several calculation methods were tested. This included codes: PN-EN 1992-1-1:2008, ACI 318-14 and fib Model Code for Concrete Structures 2010. The analysis also consists of authorial methods published in technical literature. Calculations of shear strengths were made based on experimental...
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Joints Of Steel Sandwich Structures
PublikacjaSteel sandwich structures are perceived as alternatives to single-skin welded structures in the shipbuilding industry due its advantages like significant reduction of mass in relation to typical single skin structure. However, beside problems with their strength properties itself, applications in real structures requires of solving the problem of joining, both for connection sandwich to sandwich as well as sandwiches to single-shell...
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Lanthanide-organic-frameworks modified ZnIn2S4 for boosting hydrogen generation under UV–Vis and visible light
PublikacjaNovel Ln-MOF with microrods shape were successfully combined with ZnIn2S4 (ZIS) microsphere and used for photocatalytic hydrogen generation under UV–Vis and visible light. The Ln-MOFs/ZIS system comprises lanthanide-carboxylate coordination networks (Tm and Gd as metal ions, and 1,3,5-benzenetricarboxylic acid (BTC) as the organic linker) deposited on ZnIn2S4 microspheres. Effect of the amount of ((Tm,Gd)-BTC) (1, 5, 10 wt%) on...
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VOLTAMMETRIC DETERMINATION OF DEOXYRIBONUCLEIC ACID PRESENCE ON A CARBON ELECTRODE
PublikacjaThis paper presents a voltammetry as a useful method to analyse DNA from different species. This electrochemical method is well know and used in different analyses. The influence of an area of working electrode and the capacity component, is shown at equals and the measurement. In voltammetry DNA measurement the capacity component is very important and must be taken into consideration. All mathematical analyses were verify at laboratory.
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Investigating BiMeVOx compounds as potential photoelectrochemical and electrochemical materials for renewable hydrogen production
PublikacjaIn this study, BiMeVOx compounds (where Me: Co, Mo, Ce, Zr) were synthesized and characterized as potential photoelectrochemical materials for solar water splitting, the hydrogen evolution reaction (HER), and oxygen evolution reaction (OER). The analysis confirmed the successful formation of phase BiMeVOx compounds with the desired crystal structure. Among the tested materials, BiCoVOx(800) showed the highest photocurrent density...
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Strength of Materials II,Lectures,DAPE,spring 21-22 (PG_00050281)
Kursy OnlineThe aim of the subject is to acquire knowledge related to the strength of materials II (mechanics of material, part 2)
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3D Hierarchical Boron-Doped Diamond-Multilayered Graphene Nanowalls as an Efficient Supercapacitor Electrode
PublikacjaSynthesis of stable hybrid carbon nanostructure for high-performance supercapacitor electrode with long life-cycle for electronic and energy storage devices is a real challenge. Here, we present a one-step synthesis method to produce conductive boron-doped hybrid carbon nanowalls (HCNWs), where sp2-bonded graphene has been integrated with and over a three-dimensional curved wall-like network of sp3-bonded diamond. The spectroscopic...
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Advances in Modelling and Analysis of Strength of Corroded Ship Structures
PublikacjaThe present study reviews the recent advances in modelling and analyses the strength of corroded ship structures. Firstly, the time-variant methodologies that consider only the mean structural element thickness loss due to corrosion degradation are identified. Corrosion degradation is regarded as the phenomenon that causes uneven thinning of specimens. This has been captured by various researchers as the loss of mechanical properties...
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Reconstruction Methods for 3D Underwater Objects Using Point Cloud Data
PublikacjaExisting methods for visualizing underwater objects in three dimensions are usually based on displaying the imaged objects either as unorganised point sets or in the form of edges connecting the points in a trivial way. To allow the researcher to recognise more details and characteristic features of an investigated object, the visualization quality may be improved by transforming the unordered point clouds into higher order structures....
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Nitrogen oxides removal from hydrogen flue gas using corona discharge in marine boilers: Application perspective
PublikacjaThis paper focuses on the combustion of hydrogen in boilers, as it appears to be a more effective method than using fuel cells for heating purposes due to higher boiler efficiency. One of the main disadvantages of hydrogen combustion in air is NOx formation. Therefore, the authors decided to introduce corona discharge as an inno- vative technique to clean hydrogen flue gas by effectively reducing NOx levels. The method involves...
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Explosive welding of metals.
PublikacjaPrzedstawiono wytwarzanie i zastosowanie łączników zgrzewanych wybuchowo oraz wpływ podłoża na ten proces.
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Strength Fracture and Complexity
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Problems of Strength and Plasticity
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STRENGTH AND CONDITIONING JOURNAL
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Flexible dye-sensitized solar cells based on Ti/TiO2 nanotubes photoanode and Pt-free and TCO-free counter electrode system
PublikacjaFlexible dye-sensitized solar cells (DSSCs) are getting more attention compared to standard glass covered DSSCs due to their unique commercial applications (e.g. tents or sail surfaces) and the possibility of rolling up into a small, portable device. In this work, titania nanotubes (TiO2 NT) modified with titania nanoparticles (TiO2 NP) were photoelectrochemically characterized as an anode for flexible dye-sensitized solar cells....
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Two-dimensional hydrogen-like atom in a weak magnetic field
PublikacjaWe consider a non-relativistic two-dimensional (2D) hydrogen-like atom in a weak, static, uniform magnetic field perpendicular to the atomic plane. Within the framework of the Rayleigh-Schr¨odinger perturbation theory, using the Sturmian expansion of the generalized radial Coulomb Green function, we derive explicit analytical expressions for corrections to an arbitrary planar hydrogenic bound-state energy level, up to the fourth...
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Influence of titanium layer on counter electrode on electrical parameters of DSSC
PublikacjaIn this paper the influence of the Ti layer thickness at counter-electrode on electrical parameters of DSSCs was examined. The transparent conductive oxide – less (TCO-less) counter electrodes (CE) with titanium layers and platinum as catalyst on Bk7 glass were prepared. Thin metallic films were deposited by means of magnetron sputtering (titanium) and Pulsed Laser Deposition (platinum). The counter electrode with Pt layer on Fluorine...
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High temperature air/steam gasification of biomass in view of hydrogen rich gas production.
PublikacjaArtykuł przedstawia opis nowej i zaawansowanej metody konwersji termochemicznej biomasy i miejskich odpadów stałych w paliwo gazowe, bogate w wodór. W porównaniu z tradycyjnym procesem gazyfikacji, w metodzie tej wykorzystuje się powietrze/parę wodną przegrzane do wysokiej temperatury (powyżej 1300 st. C). Przegrzanie powietrza lub pary wodnej odbywa się z zastosowaniem ceramicznego przegrzewacza wysokotemperaturowego. W celu...
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Hydrogen rich gas production from high temperature air/steam gasification of biomass
PublikacjaW pracy przedstawiono nowoczesną technikę konwersji biomasy oraz stałych odpadów komunalnych w celu produkcji paliwa gazowego bogatego w wodór. Opisany proces gazyfikacji przebiega w wysokiej temperaturze przy obniżonej koncentracji tlenu i udziale pary wodnej. Dzięki temu możliwa jest produkcja gazów palnych, w szczególności H2, który można wykorzystać do produkcji energii elektrycznej i cieplnej.
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Partitioning of heavy metals in sub-surface flow treatment wetlands receiving high-strength wastewater
PublikacjaThe retention of heavy metals at two pilot-scale treatment wetlands (TWs), consisting of two vertical flow beds (VSSF) followed by a horizontal flow bed (HSSF) was studied. The TWs received highstrength wastewater: reject waters from sewage sludge centrifugation (RW) and landfill leachate (LL). The concentrations of metals: Fe, Mn, Zn, Al, Pb, Cu, Cd, Co, Ni were measured in treated wastewater, substrate of the beds and in plant...
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Compression and Fatigue Testing of High-Strength Thin Metal Sheets by Using an Anti-Buckling Device
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Ternary LaNi4.75M0.25 hydrogen storage alloys: Surface segregation, hydrogen sorption and thermodynamic stability
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Performance of underwater data transmission using incoherent modulation MFSK in very shallow waters
PublikacjaEnsuring universal and stable underwater communication in shallow waters for various environmental conditions is a difficult scientific and engineering task. In particular, this applies to underwater communication systems that use acoustic waves in very shallow underwater channels, where multipath propagation permanently occurs. The article provides assumptions for a system working with incoherent M-ary Frequency Shift Keying (MFSK)...
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The resistance of S235JR steel to cavitation erosion
PublikacjaThe erosion resistance of S235JR steel to flow cavitation was investigated. In order to understand an influence of steel properties and cavitation intensities on the degradation mechanisms, low-carbon S235JR steel was tested in the as-received state and after thermal treatment (annealing) under four different flow velocities. Annealing decreased steel hardness, which made S235JR steel less resistant to cavitation erosion. The performed...
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Microstructural evolution and mechanical behavior of activated tungsten inert gas welded joint between P91 steel and Incoloy 800HT
PublikacjaThis study examines the welded joint between P91 steel and Incoloy 800HT using the Activated Tungsten Inert Gas (A-TIG) welding process. The focus is on analyzing the microstructure and evaluating the mechanical properties of joints made with different compositions of activating flux. Owing to the reversal of the Marangoni effect in which the conventional direction of molten metal flow in the weld pool is reversed due to the application...
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ADAPTIVE IDENTIFICATION OF TIME-VARYING IMPULSE RESPONSE OF UNDERWATER ACOUSTIC COMMUNICATION CHANNEL
PublikacjaThe transmission properties of underwater acoustic communication channel can change dynamically due to the movement of acoustic system transmitter and receiver or underwater objects reflecting transmitted signal. The time-varying impulse response measurement and estimation are necessary to match the physical layer of data transmission to instantaneous channel propagation conditions. Using the correlative measurement method, impulse...
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Assessment of High-Temperature Oxidation Properties of 316L Stainless Steel Powder and Sintered Porous Supports for Potential Solid Oxide Cells Applications
PublikacjaIn this work, oxidation properties of austenitic 316L stainless steel powder and sintered porous support were investigated at the temperature range of ~600-750 °C for 100 hours in ambient air. Oxidation kinetics was determined by continuous thermogravimetry and analyzed employing parabolic rate law. It was observed that oxidation leads to the formation of an oxide scale, with substantial oxidation occurring at ≥ 650 °C in the powder....
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Adaptive Identification of Underwater Acoustic Channel with a Mix of Static and Time-Varying Parameters
PublikacjaWe consider the problem of identification of communication channels with a mix of static and time-varying parameters. Such scenarios are typical, among others, in underwater acoustics. In this paper, we further develop adaptive algorithms built on the local basis function (LBF) principle resulting in excellent performance when identifying time-varying systems. The main drawback of an LBF algorithm is its high complexity. The subsequently...
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Niszczenie wodorowe złączy spawanych ze stali S355 = Hydrogen degradation of welded joints of S355 steel
PublikacjaW artykule przedstawiono ocenę podatności na niszczenie wodorowe złączy spawanych ze stali S355. Jako parametry niszczenia wodorowego wybrano względne wartości energii zniszczenia, wydłużenia, przewężenia i wytrzymałości na rozciąganie. Parametry te wyznaczono w próbie odkształcania z małą prędkością na próbkach okrągłych, gładkich. Stwierdzono, że stal S355w środowisku kwaśnym podczas polaryzacji katodowej, jest bardziej skłonna...
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Testing the Wide-Sense Stationarity of Bandpass Signals for Underwater Acoustic Communications
PublikacjaThe Underwater Acoustic Communication (UAC) systems work in communication channels characterized by a large variety of multipath propagation conditions that can additionally change over time. Designing a reliable communication system requires knowledge of the transmission parameters of the channel. There is a need for the development of adaptive signaling schemes that would dynamically optimize the signal parameters of the physical...
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HIGH TEMPERATURES-HIGH PRESSURES
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Corrosion performance of super duplex stainless steel and pipeline steel dissimilar welded joints: a comprehensive investigation for marine structures
PublikacjaThis study investigates the corrosion behavior of dissimilar gas tungsten arc (GTA) welded joints between super duplex stainless steel (sDSS 2507) and pipeline steel (X-70) using electrochemical and immersion corrosion tests. The GTA welds were fabricated using ER2594 and ER309L fller metals. The study examined the electrochemical characteristics and continuous corrosion behavior of samples extracted from various zones of the weldments...
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Application of BDD thin film electrode for electrochemical decomposition of heterogeneous aromatic compounds
PublikacjaThe aim of the presented study is to investigate the applicability of electrochemical oxidation of aromatic compounds containing heteroatoms, e.g. waste from production of pesticides or pharmaceutics, at a borondoped diamond (BDD) electrode. The BDD electrodes were synthesized by microwave plasma enhanced chemical vapour deposition (MW PE CVD). Investigation of the electrode surface by optical microscopy and scanning electron microscopy...