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Wyniki wyszukiwania dla: OPERATING CONDITIONS
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ANALIZA STANU TECHNICZNEGO RUROCIĄGÓW: WODY PRZeMYSŁOWEJ I SOLANKI
PublikacjaPracę wykonano na zlecenie Przedsiębiorstwa Badawczo-Wdrożeniowego "HYDRO-POMP" Sp. z o.o. ul. Wróblewskiego 19, 93-578 Łódź. Wykonawcą zlecenia jest Politechnika Gdańska, Wydział Chemiczny, Katedra Elektrochemii, Korozji i Inżynierii Materiałowej, 80-233 Gdańsk, ul. G. Narutowicza 11/12. Celem pracy była analiza stanu technicznego i badania dwóch rurociągów: solanki oraz wody przemysłowej. Badania wykonywano w warunkach terenowych...
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FFT analysis of temperature modulated semiconductor gas sensor response for the prediction of ammonia concentration under humidity interference
PublikacjaThe increasing environmental contamination forces the need to design reliable devices for detecting of the volatile compounds present in the air. For this purpose semiconductor gas sensors, which have been widely used for years, are often utilized. Although they have many advantages such as low price and quite long life time, they still lack of long term stability and selectivity. Namely, environmental conditions have significant...
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TEST METHOD FOR DETERMINING THE CHEMICAL EMISSIONS OF A MARINE DIESEL ENGINE EXHAUST IN OPERATION
PublikacjaThe article briefly describes the problem of air pollution caused by sea-going ships and the resulting restrictions on the emission of toxic and harmful chemical compounds in the exhaust of marine engines, introduced by the International Maritime Organization (IMO) under the International Convention for the Prevention of Sea Pollution from Ships (MARPOL 73/78). Such emissions provide a significant metrological problem, not only...
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Loosely-Tied Distributed Architecture for Highly Scalable E-Learning System
PublikacjaVast majority of modern e-learning products are based on client-server architecture and utilization of web-based technologies (WBT). Such approach permits easy creation of e-learning systems that do not require a complex, operating system dependant client software. Unfortunately there are also drawbacks of such solution. Because of the majority of mechanisms are located on the server, its usage levels trend to build up quickly...
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Voltage Control of a Stand-Alone Multiphase Doubly Fed Induction Generator
PublikacjaThis article presents a multiphase doubly fed induction generator (MDFIG) with a dedicated and unique control algorithm in a stand-alone wind energy conversion system. The algorithm has been developed and elaborated in the case of different emergency modes. Compared with the traditional double-fed induction generator, the MDFIG has increased reliability, reduced current level per phase, and low rotor harmonic currents. The control...
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Corrosion hazards and inhibitor protection in the seawater injection system on the Baltic sea rig
PublikacjaOil extraction efficiency in LOTOS Petrobaltic Company is increased by means of injection of seawater into an oilfield aquifer, which is implemented on the Baltic Beta rig, operating on the Baltic Sea. Operational experience has shown a significant degree of corrosion aggressiveness in the injected water, which necessitates frequent repairs of the seawater injection installation. Evaluation of the corrosion phenomena is crucial...
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Kriging metamodels and design re‐utilization for fast parameter tuning of antenna structures
PublikacjaThe paper addresses the problem of computationally efficient electromagnetic (EM)‐driven design closure of antenna structures. The foundations of the presented approach are fast kriging interpolation metamodels, utilized for two purposes: (a) producing a good starting point for further parameter tuning, and (b) yielding a reasonable Jacobian matrix estimate to jump‐start the optimization procedure. The models are rendered using...
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On topology optimization of large deformation contact-aided shape morphing compliant mechanisms
PublikacjaA topology optimization approach for designing large deformation contact-aided shape morphing compliant mechanisms is presented. Such mechanisms can be used in varying operating conditions. Design domains are described by regular hexagonal elements. Negative circular masks are employed to perform dual task, i.e., to decide material states of each element and also, to generate rigid contact surfaces. Each mask is characterized by...
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NEW DESIGNS OF MAGNETIC FLUID SEALS FOR RECIPROCATING MOTION
PublikacjaT he operating conditions of magnetic fluid seals during reciprocating motion are so different from those observed in rotating motion that the use of their conventional structures for reciprocating motion seals yields no good results. The analysis of the sealing mechanism of magnetic fluid seals in reciprocating motion shows that the operation of these seals is affected by the carry-over phenomenon and magnetic fluid...
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Performance-Driven Inverse/Forward Modeling of Antennas in Variable-Thickness Domains
PublikacjaDesign of contemporary antenna systems is a challenging endeavor. The difficulties are partially rooted in stringent specifications imposed on both electrical and field characteristics, demands concerning various functionalities, but also constraints imposed upon the physical size of the radiators. Furthermore, conducting the design process at the level of full-wave electromagnetic (EM) simulations, otherwise dictated by reliability,...
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Cellular network quality evaluation at a university campus on the eve of 5G
PublikacjaThanks to the availability of mobile devices and the spread of broadband access around the world, the number of network users continues to grow. This has raised user awareness when it comes to the quality of content they consume. Many service providers and operators focus on monitoring QoN (Quality of Network) and QoS (Quality of Service) parameters, particularly those influenced by bandwidth and latency. However, for most end-users,...
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Advances in analysis, quantification and modelling of N2O emission in SBRs under various DO set points
PublikacjaNitrous oxide (N2O), considered a major greenhouse gas (GHG) in wastewater treatment plants (WWTPs), is produced during both nitrification and denitrification processes; hence, it needs to be controlled by internal and external strategies. Various factors, such as DO, temperature, and pH, could be incorporated into the mitigation of emissions in WWTPs. In this research, potential operational strategies were investigated in order...
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Elucidating charge transfer process and enhancing electrochemical performance of laser-induced graphene via surface engineering with sustainable hydrogel membranes: An electrochemist's perspective
PublikacjaLaser-induced graphene (LIG) has emerged as a promising solvent-free strategy for producing highly porous, 3D graphene structures, particularly for electrochemical applications. However, the unique character of LIG and hydrogel membrane (HM) coated LIG requires accounting for the specific conditions of its charge transfer process. This study investigates electron transfer kinetics and the electroactive surface area of LIG electrodes,...
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Electrochemical Production of Sodium Hypochlorite from Salty Wastewater Using a Flow-by Porous Graphite Electrode
PublikacjaThe production of sodium hypochlorite (NaOCl) from salty wastewater using an electrochemical cell has several advantages over other methods that often require hazardous chemicals and generate toxic waste, being more sustainable and environmentally friendly. However, the process of producing sodium hypochlorite using an electrochemical cell requires careful control of the operating conditions, such as the current density, flow rate,...
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Bioreactors and biophoton-driven biohydrogen production strategies
PublikacjaGiven the current issues with global warming and rising greenhouse gas emissions, biohydrogen is a viable alternative fuel option. Technologies to produce biohydrogen include photo fermentation, dark fermentation, direct and indirect bio-photolysis, and two-stage fermentation. Biological hydrogen generation is a green and promising technique with mild reaction conditions and low energy consumption compared to thermochemical and...
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Ecological bearing systems for water turbines – research and development at Gdansk University of Technology
PublikacjaIncreasing requirements for environmental protection make it necessary to introduce new materials and designs. Hydroelectric power plants operating in direct contact with water reservoirs and rivers are potentially endangering water cleanliness, hence they should also be modernized in the way minimizing the environmental hazards. A lot of progress in this field has been achieved in last decades, but still there is much work to...
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Towards Designing an Innovative Industrial Fan: Developing Regression and Neural Models Based on Remote Mass Measurements
PublikacjaThis article presents the process of the construction and testing a remote, fully autonomous system for measuring the operational parameters of fans. The measurement results obtained made it possible to create and verify mathematical models using linear regression and neural networks. The process was implemented as part of the first stage of an innovative project. The article presents detailed steps of constructing a system to...
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Improved-Efficacy EM-Driven Optimization of Antenna Structures Using Adaptive Design Specifications and Variable-Resolution Models
PublikacjaOptimization-driven parameter tuning is an essential step in the design of antenna systems. Although in many cases it is still conducted through parametric studies, rigorous numerical methods become a necessity if truly optimum designs are sought for, and the problem intricacies (number of variables, multiple goals, constraints) make the interactive approaches insufficient. The two practical considerations of electromagnetic (EM)-driven...
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Expedited Yield-Driven Design of High-Frequency Structures by Kriging Surrogates in Confined Domains
PublikacjaUncertainty quantification is an important aspect of engineering design, also pertaining to the development and performance evaluation of high-frequency structures systems. Manufacturing tolerances as well as other types of uncertainties, related to material parameters (e.g., substrate permittivity) or operating conditions (e.g., bending) may affect the characteristics of antennas or microwave devices. For example, in the case...
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Opracowanie technologii naprawy nieciągłości metalicznych w połączeniach spawanych, w konstrukcji podpór przednich pras filtracyjnych położonych na terenie Grupowej Oczyszczalni Ścieków Dębogórze
PublikacjaCelem niniejszej pracy jest opracowanie wytycznych technologicznych, których wdrożenie pozwoli na usunięcie istniejących pęknięć, co przyczyni się do stabilizacji wymiarowej podpór oraz całej konstrukcji pras. Osiągniecie tego celu wymaga podjęcia następujących działań: - ocenę stanu technicznego naprawianego komponentu- podpór przednich trzech pras filtracyjnych, - określenie własności spawalniczych materiału naprawianego, -...
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SEA SLUGG - Student Experiment Again: Submarine Launched into μGravity from Gdansk
PublikacjaSearch for extraterrestrial life has been a drive wheel for space technology research for half a century. Recentresearch in astrobiology suggests that underwater oceans on Jovian moon Europa, Saturnian moon Titan and possiblyasteroids may be a potential habitat for such microbial life. The unique combination of an actively recycled ice shelland rocky, possibly magmatic interior may give rise to a geochemical system suitable...
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Compliance tests of the polymer layers used as hydrodynamic bearing coatings
PublikacjaOperational experience and scientific investigations results showed that polymer lined hydrodynamic bearings can withstand more severe operating conditions compared than white metal bearings. PTFE and PEEK-based coatings are the most frequently used as Babbitt alternatives. Both polymers differ significantly from the each other in material properties. According to catalogue data compression modulus of PTFE, it is about an order...
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Full scale CFD seakeeping simulations for case study ship redesigned from V-shaped bulbous bow to X-bow hull form
PublikacjaIncreasing propulsion efficiency, safety, comfort and operability are of the great importance, especially for small ships operating on windy sites like the North Sea and the Baltic Sea. Seakeeping performance of ships and offshore structures can be analysed by different methods and the one that is becoming increasingly important is CFD RANS. The recent development of simulation techniques together with rising HPC accessibility...
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Pressure drop related to flow maldistribution in a model minichannel plate heat exchanger
PublikacjaThe paper describes the issues related to the pressure drop that accompanies the phenomenon of maldistribution of working fluid between the channels of a model minichannel plate heat exchanger. The research concerns a single exchanger's plate containing 51 (in every geometry) parallel rectangular minichannels of hydraulic diameters 461 µm, 571 µm, 750 µm and 823 µm. In addition, the more complex geometry has been investigated,...
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Selection of C-Type Filters for Reactive Power Compensation and Filtration of Higher Harmonics Injected into the Transmission System by Arc Furnaces
PublikacjaThis article presents a method for selecting the elements of a C-type filter working with a conventional LC-type filter for compensating reactive power and filtering out higher harmonics generated by arc furnaces and ladle furnaces. The study was conducted in a steel mill supplied by a 110 kV transmission system, where higher harmonic currents and nonlinear loads were measured. A series of computer simulations were performed under...
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Optimization of the Relative Humidity of Reactant Gases in Hydrogen Fuel Cells Using Dynamic Impedance Measurements
PublikacjaWater management is a key factor affecting the efficiency of proton exchange membrane fuel cells (PEMFCs). The currently used monitoring methods of PEMFCs provide limited information about which processes or components that humidity has a significant impact upon. Herein, we propose the use of a novel approach of impedance measurements using a multi-sinusoidal perturbation signal, which enables impedance measurements under dynamic...
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Chemorezystancyjny czujnik gazu na bazie polimeru przewodzącego PEDOT
PublikacjaPolimery przewodzące, takie jak Poli(3,4-etylenodioksytiofen) (PEDOT) są atrakcyjnymi materiałami elektrodowymi, które posiadają takie zalety, jak biokompatybilność, duża przewodność i elastyczność. Elektroprzewodzące polimery można otrzymać w wyniku chemicznej polimeryzacji lub elektropolimeryzacji. W niniejszej pracy przedstawiono zostanie koncepcja czujnika gazów składająca się z elektrody grzebieniowej oraz polimeru przewodzącego...
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ENERGY AND EMISSION QUALITY RANKING OF NEWLY PRODUCED LOW-SULPHUR MARINE FUEL
PublikacjaThe article describes the methodology of engine tests on new types of low-sulphur marine fuels in laboratory conditions in order to conduct a comprehensive assessment of their suitability for powering full-size marine engines. The innovativeness of the proposed solution consists of adapting the laboratory Diesel Engine Test Bed to carry out experimental tests using residual and alternative fuels so that it is possible to imitate...
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A dissimilar welded joint of grade 92 steel and AISI 304L steel obtained using IN82 buttering and IN617 fller: relationship of microstructure and mechanical properties
PublikacjaUnfavourable operating conditions of equipment in the energy industry resulting from high-temperature loads determine the need to use special materials and technological solutions, including welding procedures. In this article, buttering using IN82 (ERNiCr-3) consumables was proposed as a method to improve the weldability of grade 92 steel joined by the gas tungsten arc welding (GTAW) process with AISI 304L (IN617 fller). The...
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Incorporation of the sulfur cycle in sustainable nitrogen removal systems - A review
PublikacjaIn wastewater treatment systems, sulfur (S) removal processes are generally based on heterotrophic sulfate (SO42−) reduction by sulfate reducing bacteria and S-dependent autotrophic denitrification by sulfur oxidizing bacteria. A combination of either two cycles (N and S) or three cycles (N, S and C) appears to be a viable approach to sustainable wastewater treatment, resulting in energy savings and reduction of sludge production....
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Dynamic mass measurement in checkweighers using a discrete time-variant low-pass filter
PublikacjaConveyor belt type checkweighers are complex mechanical systems consisting of a weighing sensor (strain gauge load cell, electrodynamically compensated load cell), packages (of different shapes, made of different materials) and a transport system (motors, gears, rollers). Disturbances generated by the vibrating parts of such a system are reflected in the signal power spectra in a form of strong spectral peaks, located usually in...
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Rapid multi-criterial design of microwave components with robustness analysis by means of knowledge-based surrogates
PublikacjaManufacturing tolerances and uncertainties concerning material parameters, e.g., operating conditions or substrate permittivity are detrimental to characteristics of microwave components. The knowledge of relations between acceptable parameter deviations (not leading to violation of design specifications) and the nominal performance (not considering uncertainties), and is therefore indispensable. This paper proposes a multi-objective...
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Smart Asset Management for District Heating Systems in the Baltic Sea Region.
PublikacjaThe purpose of this review is to provide insight and a comparison of the current status of district heating (DH) systems for selected Baltic Sea countries (Denmark, Germany, Finland, Latvia, Lithuania, Poland, and Sweden), especially from viewpoints of application and solutions of novel smart asset management (SAM) approaches. Furthermore, this paper considers European projects ongoing from 2016, involving participants from the...
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Low-cost data-driven modelling of microwave components using domain confinement and PCA-based dimensionality reduction
PublikacjaFast data-driven surrogate models can be employed as replacements of computationally demanding full-wave electromagnetic simulations to facilitate the microwave design procedures. Unfortunately, practical application of surrogate modelling is often hindered by the curse of dimensionality and/or considerable nonlinearity of the component characteristics. This paper proposes a simple yet reliable approach to cost-efficient modelling...
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Methodology for determining the elemental composition, as well as energy and ignition properties of the low-sulfur marine fuels
PublikacjaThe key metrological issue of substance and energy balance in research engines is the precise determination of the elemental composition of the applied fuel and its net calorific value. This makes it possible to calculate the amount of heat brought with the fuel into the combustion chamber, as well as the amount and gas composition of the exhaust. However, to fully assess the energy quality of the fuel used, its ignition properties...
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Visualization of the surface of the Nafion membrane
Dane BadawczeFuel cells use the chemical energy of hydrogen or other fuels to produce electricity. If the fuel is hydrogen, the only products are electricity, water and heat. Fuel cells are unique in the variety of their potential applications, they can use a wide variety of fuels. They are also highly scalable devices that can power both cars and mobile phones....
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Wpływ wybranych parametrów środowiska na przebieg degradacji rur okładzinowych ze stali P110
PublikacjaMateriały używane na orurowanie odwiertów w poszukiwaniu i wydobyciu ropy i gazu poddawane są niekorzystnym warunkom eksploatacji takich jak: podwyższona temperatura, wysokie ciśnienie, turbulentny przepływ korozyjnych cieczy z zawieszonymi cząstkami stałymi. Jednym z gatunków stali używanych do produkcji rur okładzinowych jest stal P110 (za normą API 5CT) będąca stalą średnio-węglową, niskostopową o wysokiej wytrzymałości. Celem...
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Evaluation of respiration capacity of VF in hybrid constructed wetland systems.
PublikacjaThree VF-beds operating in hybrid constructed wetlands in configuration HF-VF-HF were analysed. These hybrid constructed wetlands provide the II stage biological treatment. They are located in Pommerania voivodship, in Sarbsk, Wiklino and Wieszyno, and their capacities are 29.5, 14.2 and 21.6 m3/d, respectively. The article focuses on performance and operation of VF-CW plants during one year. Based on removal of organic matter...
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Effect of Vascular Lumen Reduction on the Performance and Energy Consumption of an Innovative Implantable LVAD
PublikacjaThis paper presents the results of a study on the effect of vascular lumen reduction on the performance of an innovative implantable LVAD (left ventricular assist device). It details the pressures in the individual cardiac chambers as a function of device frequency. In addition, mass flow rates and energy consumption of the device are examined, varying with lumen reduction and operating frequency. While the lumen reduction of the...
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ISSUE OF MAKING DECISIONS WITH REGARD TO SHIP TRAFFIC SAFETY IN DIFFERENT SITUATIONS AT SEA
PublikacjaThe paper refers to the possibilities of making operational decisions that would enable to ensure safety to a ship in the event of application of the statistical decision theory with consideration of an expected value of consequences as a criterion for making such a decision. General description includes conditions for carrying out transportation tasks by ships and it has been shown that following this description it is possible...
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Extremal thermal loading of a bifurcation pipe
PublikacjaThe subject of considerations is a spherical bifurcation pipe of a live steam made of steel P91, which is an element of a block of coal-fired power plant working with a 18K370 turbine. As experience shows, it is a very sensitive element of the boiler pipelines. An extreme work scenario for such a block has been adopted, in which the turbine is shutting down to a warm state three times in 24 hours. This is an action dictated by...
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Reliable Surrogate Modeling of Antenna Input Characteristics by Means of Domain Confinement and Principal Components
PublikacjaA reliable design of contemporary antenna structures necessarily involves full-wave electromagnetic (EM) analysis which is the only tool capable of accounting, for example, for element coupling or the effects of connectors. As EM simulations tend to be CPU-intensive, surrogate modeling allows for relieving the computational overhead of design tasks that require numerous analyses, for example, parametric optimization or uncertainty...
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Helium-assisted, solvent-free electro-activation of 3D printed conductive carbon-polylactide electrodes
PublikacjaFused filament fabrication is one of the most rapidly developing 3D printing techniques, with numerous applications, including in the field of applied electrochemistry. Here, the utilisation of conductive carbon black polylactic acid (CB-PLA) for 3D printouts is the most promising. To use CB-PLA as an electrode material, an activation process must be performed, removing the polymer matrix and uncovering the electrically conductive...
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Assessing Roadside Hybrid Energy Absorbers Using the Example of SafeEnd
PublikacjaA combination of crash cushion and end-terminal, hybrid energy absorbing devices have been in use worldwide for a few years already. They include SafeEnd, a system Poland has recently introduced. Some road authorities have raised concerns as regards the operating conditions of the devices and how they work together with safety barriers. The objective of this research is to clarify the concerns and answer the following questions:...
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Wpływ sposobu odwzorowania pojazdu szynowego na odpowiedź dynamiczną przęsła mostowego
PublikacjaW pracy przedstawiono rezultaty analiz numerycznych oraz badań eksploatacyjnych dwóch przęseł mostowych wymuszonych ruchomym pojazdem szynowym. Pojazd odwzorowano za pomocą czterech modeli uproszczonych: strumienia sił skupionych, strumienia mas skupionych oraz strumieni oscylatorów jedno- i dwumasowych. Analizy numeryczne wykonano przy wykorzystaniu MES. Potrzebne parametry dynamiczne wyznaczono na podstawie wyników identyfikacji...
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Role of buttering layer composition on microstructural heterogeneity and mechanical properties of Alloy 617 and P92 steel dissimilar welded joints for future Indian AUSC program
PublikacjaRestrictive operating conditions (even exceeding 700 °C) of materials in advanced ultra super critical (AUSC) power plants and the need to minimize manufacturing and maintenance costs require the production of dissimilar metal welded joints (DMW). Significant differences in the physical and chemical properties of welded materials lead to phenomena that reduce the weldability of the metals used and force the search for solutions...
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Safety issues referred to induced sheath voltages in high-voltage power cables – case study
PublikacjaLoad currents and short-circuit currents in high-voltage power cable lines are sources of the induced voltages in the power cables’ concentric metallic sheaths. When power cables operate with single-point bonding, which is the simplest bonding arrangement, these induced voltages may introduce an electric shock hazard or may lead to damage of the cables’ outer non-metallic sheaths at the unearthed end of the power cable line. To...
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Physicochemical Properties and Application of Silica-Doped Biochar Composites as Efficient Sorbents of Copper from Tap Water
PublikacjaThis article concerns research on new sorption materials based on silica-doped activated carbon. A two-stage synthesis involved pyrolysis of plant material impregnated in a water glass solution , followed by hydrothermal activation of the pyrolysate in KOH solution. The resulting composite can be used as a sorbent in drinking water filters. The proposed method of synthesis enables the design of materials with a surface area...
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Modeling the impact of discretizing rotor angular position on computation of field-oriented current components in high speed electric drives
PublikacjaModern drives consist of alternating current electric motors, and the field-oriented control (FOC) of such motors enables fast, precise, and robust regulation of a drive's mechanical variables such as torque, speed, and position. The control algorithm, implemented in a microprocessor, requires feedback from motor currents, and the quality of this feedback is essential to a drive's control properties. Motor phase currents are sampled...
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Polish FDI in Central Asian Countries
PublikacjaSince gaining independence, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan gradually opened their markets to foreign investors. Before Poland’s accession to the European Union, the activities of Polish investors in Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan were based on bilateral treaties concluded by Poland with those countries. Later, except Turkmenistan, they were governed by the partnership...