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Search results for: OPERATION
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A Model for Risk Assessment and Management of Construction Projects in Urban Conditions
PublicationThe authors are seeking new methods for improving the efficiency of the investments associated with the maintenance and operation of existing civil engineering structures. It is demonstrated how the knowledge about the elements of construction and operation phases and their relationships, combined with monitoring data can be used for more effective management of the risks associated with civil engineering projects. The methodology...
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ANALYSIS OF THE POSSIBILITIES OF HIGH SPEED SHAFT BEARING SYSTEM DURABILITY INCREASE
PublicationDuring the operation of wind turbines with a gearbox of traditional configuration, a high failure rate of high-speed shaft bearings is observed. Such a high failures frequency is not reflected in standard bearing durability calculation methods, which can be attributed to atypical failure mechanism. To avoid observed problems in the 1.5 MW wind turbine, the modification of the existing bearing system is proposed. Multiple options,...
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Multi-Objective Water Distribution Systems Control of Pumping Cost, Water Quality, and Storage-Reliability Constraints
PublicationThis work describes a multi-objective model for trading-off pumping cost and water quality for water distribution systems operation. Constraints are imposed on flows and pressures, on periodical tanks operation, and on tanks storage. The methodology links the multi-objective SPEA2 algorithm with EPANET, and is applied on two example applications of increasing complexity, under extended period simulation conditions and variable...
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The influence of dynamic load changes on temporary impedance in hydrogen fuel cells, selection and validation of the electrical equivalent circuit
PublicationTo achieve optimal performance of a fuel cell, a reliable monitoring and diagnostic method is required. The currently utilized methods give limited information or they are impossible to use under dynamic working conditions. To obtain comprehensive information about the fuel cell operation we utilized novel dynamic electrochemical impedance spectroscopy. Impedance measurements in dynamic mode were performed on a hydrogen fuel cell,...
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An integral-differential method for impedance determination of the hydrogen oxidation process in the presence of carbon monoxide in the proton exchange membrane fuel cell
PublicationThe impedance of a proton exchange membrane fuel cell powered by hydrogen contaminated with carbon monoxide, ranging from 150 to 300 ppb, is measured and discussed. The tested range of CO concentration complied with the fuel standard specified in the ISO standards. Studies of influence of CO contamination on operation of PEMFC are crucial for further development and commercialization of fuel cells for automotive applications. Based...
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Integrated Three-Level Dual-Phase Inverter
PublicationIn view of reducing the number of inverter legs that provide dual-phase, three-level output voltages (as may be needed in an uninterruptible power supply), and that also provide a wide range of output frequencies (as needed in an advanced motor drive system with wide speed ranges), a three-level, dual-phase inverter topology is presented in this paper. Its three-level attribute was based on the F-type inverter topological concept,...
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The allergic and irritating reactions to metallic implants with trauma - orthopaedic patients
PublicationThe article presents the analysis of clinical operation complications after the treatment of long bones by mean of ostheosynthesis with the use of metal implants and endoprothesoplastic of hip joints.
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Analysis of pressure ratio in the intake in dependence on high-voltage behaviours
PublicationPower control in spark ignition engines by regulating the intake air is performed. The control unit needs information about the air pressure conditions which then enters the combustion chamber. The information about the intake air pressure is an important quantity for optimal control of combustion mixtures. The paper describes some types of sensors that are used to measure the air intake temperature. Air pressure in the intake...
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Pipelined division of signed numbers with the use of residue arithmetic for small number range with the programmable gate array
PublicationIn this work an architecture of the pipelined signed residue divider for the small number range is presented. Its operation is based on reciprocal calculation and multiplication by the dividend. The divisor in the signed binary form is used to compute the approximated reciprocal in the residue form by the table look-up. In order to limit the look-up table address an algorithm based on segmentation of the divisor into two segments...
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A robust 18-pulse diode rectifier with coupled reactors
PublicationThe article presents the principle of operation and selected results of simulation and laboratory tests of the 18-pulse rectifier system with coupled reactors and small series active power filter. The presented system makes it possible to reduce, especially in distribution supply networks, undesired higher current harmonics. The 18-pulse nature of operation of the rectifier is reached using a set of coupled three-phase network...
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Open-Phase Fault Detection Method for Sensorless Five-Phase Induction Motor Drives with an Inverter Output Filter
PublicationThe paper presents the sensorless five-phase induction motor drive implementation with an inverter output filter with third harmonic injection. For the sensorless operation, the required observers are presented for the first and third harmonics with consideration of the inverter output filter. Moreover, the interaction of the observers and the control system is capable to handle a deactivation of one or two phases, which improves...
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The electrical properties mesurements of DIR-SOFC with Ce0.8Fe0.2O2-s functional layer
Open Research DataThe dataset includes the electrical properties mesurements of SOFC with Ce0.8Fe0.1O2-s layer. Samples were produced using aqueous soft chemistry methods (microemulsion method) and applied in form of a layer onto the anode of the commercial SOFC. The SOFC was working under biogas feeding at 750oC. The layers were sintered at 1100oC.
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The electrical properties mesurements of DIR-SOFC with Ce0.8Co0.2O2-s functional layer
Open Research DataThe dataset includes the electrical properties mesurements of SOFC with Ce0.8Co0.1O2-s layer. Samples were produced using aqueous soft chemistry methods (microemulsion method) and applied in form of a layer onto the anode of the commercial SOFC. The SOFC was working under biogas feeding at 750oC. The layers were sintered at 1100oC.
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Elemental composition of deposited sediments at the tram-route junction
Open Research DataThis data set contains the elemental composition results of deposited sediments collected at the tram-route junction in Gdańsk. Sample collection began in July 2022, when the tram lines were completed and before the rails were scrubbed (27/07/2022). The second sample round was carried out following rail scrubbing in October 2022 (7/10/2022). Since February...
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The electrical properties mesurements of DIR-SOFC with Ce0.8Mn0.2O2-s functional layer
Open Research DataThe dataset includes the electrical properties mesurements of SOFC with Ce0.8Mn0.1O2-s layer. Samples were produced using aqueous soft chemistry methods (microemulsion method) and applied in form of a layer onto the anode of the commercial SOFC. The SOFC was working under biogas feeding at 750oC. The layers were sintered at 1100oC.
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The electrical properties mesurements of DIR-SOFC with Ce0.8Ni0.2O2-s functional layer
Open Research DataThe dataset includes the electrical properties mesurements of SOFC with Ce0.8Ni0.1O2-s layer. Samples were produced using aqueous soft chemistry methods (microemulsion method) and applied in form of a layer onto the anode of the commercial SOFC. The SOFC was working under biogas feeding at 750oC. The layers were sintered at 1100oC.
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The electrical properties mesurements of DIR-SOFC with CeO2-s functional layer
Open Research DataThe dataset includes the electrical properties mesurements of SOFC with CeO2-s layer. Samples were produced using aqueous soft chemistry methods (microemulsion method) and applied in form of a layer onto the anode of the commercial SOFC. The SOFC was working under biogas feeding at 750oC. The layers were sintered at 1100oC.
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The electrical properties mesurements of DIR-SOFC with Ce0.8Cu0.2O2-s functional layer
Open Research DataThe dataset includes the electrical properties mesurements of SOFC with Ce0.8Cu0.1O2-s layer. Samples were produced using aqueous soft chemistry methods (microemulsion method) and applied in form of a layer onto the anode of the commercial SOFC. The SOFC was working under biogas feeding at 750oC. The layers were sintered at 1100oC.
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Evaluation of VSC Impact on Power System Using Adequate P-Q Capability Curve
PublicationRenewable energy sources, which are becoming increasingly popular, often use a voltage source converter (VSC) for connection to the power system. Assessing the effects of connecting such a source to the power system is essential to ensure the proper operation of the power system and the connected source. For this purpose, it is necessary to know the range of active and reactive power generation by the converter. The authors indicate...
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Areas of Fan Research—A Review of the Literature in Terms of Improving Operating Efficiency and Reducing Noise Emissions
PublicationFans as industrial devices are among the most significant single recipients of driving energy. Therefore, they represent an important area of energy savings to reduce CO2 emissions. The ubiquity of fans and their operation under conditions different from the optimum provides an opportunity for more significant global reductions in the energy used to drive them. The second important aspect, besides energy efficiency, related to...
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CMOS implementation of an analogue median filter for image processing in real time
PublicationAn analogue median filter, realised in a 0.35 μm CMOS technology, is presented in this paper. The key advantages of the filter are: high speed of image processing (50 frames per second), low-power operation (below 1.25 mW under 3.3 V supply) and relatively high accuracy of signal processing. The presented filter is a part of an integrated circuit for image processing (a vision chip), containing: a photo-sensor matrix, a set of...
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Reliable underwater communication system for shallow coastal waters
PublicationThis paper presents a reliable and robust low data rate spread spectrum approach which is implemented in the acoustic underwater communication system for shallow coastal waters. It shows operation assumptions of spread spectrum techniques based on the wellknown Shannon equation. It describes two methods of spread spectrum: frequency hopping spread spectrum and direct sequence spread spectrum; their block diagram and their characteristics...
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A Novel Multicast Architecture of Programmable Networks
PublicationIn the paper a multicast architecture for programmable networks based on separation of group management and network control tasks is proposed. Thanks to this separation, services which want to make use of multicast communications no longer have to implement low-level network functionalities and their operation is greatly simplified. Abstracting service’s view of the network into a fully connected cloud enables us to transparently...
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Implementation of DEIS for reliable fault monitoring and detection in PEMFC single cells and stacks
PublicationDynamic Electrochemical Impedance Spectroscopy (DEIS) was presented as novel method for diagnostic and monitoring of PEMFC stack and single cells operation. Impedance characteristics were obtained simultaneously with current - voltage characteristics for stack and each individual cell. Impedance measurements were performed in galvanodynamic mode. It allowed to compare performance of each cell and identification of faulty cell operation...
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Transient States during Short-circuit in a Line Powered by UPS and its Impact on Earth Fault Loop Impedance Measurement and Power Quality
PublicationThe short-circuit in a line powered by Uninterruptible Power Supply (UPS) during different UPS operation modes is presented in the article. The transient state condition related to the short-circuit in a line fed from double conversion On-line UPS is discussed in detail. The results of the measurements of earth fault loop impedance (FLI) in circuits powered by UPS with the instruments of various manufacturers are presented. The...
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COMPARATIVE ANALYSIS OF RESULTS OF APPLICATION OF MARKOV AND SEMI-MARKOV PROCESSES TO RELIABILITY MODELS OF MULTI-STATE TECHNICAL OBJECTS
PublicationDuring rational operation of technical objects and systems various operational decisions are made and decision-making process itself should be consisted in selecting that considered most favourable out of all possible to be taken. Choice of such decision is possible after taking into account many different information items but it never be completely correct without accounting for data and indices dealing with reliability. In...
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Thermal failure of a second rotor stage in heavy duty gas turbine
PublicationThe impulse mode of operation and the supply of various types of fuels causes frequent failures even in the heavy duty gas turbines. The paper presents the ravages of second rotor stage failure in a gas turbine. The excessive thermal elongation rise caused by fuel change was indicated as the main cause. We applied nonlinear numerical analysis, preceded by thermodynamic calculations of the turbine and visual inspection of the effects...
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Chip suction system in circular sawing machine: empirical research and computational fluid dynamics numerical simulations
PublicationThe experimental analysis of the wood chip removing system during its redesigning in the existing sliding table circular saw and computational fluid dynamic (CFD) numerical simulations of the air flow process is presented in the paper. The attention was focused on the extraction hood and the bottom shelter of the actual existing system. The main aim was to perform experimental research on the pressure distribution inside the...
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Optimization of the Relative Humidity of Reactant Gases in Hydrogen Fuel Cells Using Dynamic Impedance Measurements
PublicationWater 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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Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines. Part II. Unsteady processes
PublicationThe second part of the article presents the results of operating diagnostic tests of a two- and three-shaft engine with a separate power turbine during the start-up and acceleration of the rotor units. Attention was paid to key importance of the correctness of operation of the automatic engine load control system, the input for which, among other signals, is the rate of increase of the exhaust gas flow temperature. The article...
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INVESTIGATION OF JOURNAL SLIDE BEARINGS UNDER THE ANGLE OF THEIR FUNCTIONING
PublicationPaper presents the structure and principle of operation of a stand for measurements of influence of the lubrication method and process on functioning of journal slide bearings in their various technical states. Measurements performed on the stand make it possible to take advantage of the new method of evaluating the influence of physical and chemical properties of lubricating oil on the coefficient of friction in the mixed friction...
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The effects of selected factors on pedestrian crossings in urban areas
PublicationPedestrian crossings are designed to help pedestrians cross a road. There are at-grade pedestrian crossings with or without traffic lights and grade separated crossings such as subways and footbridges. Pedestrian crossings may be located next to a junction or on road sections between junctions. Where at-grade crossings are involved, pedestrians and motorists interact, which may lead to dangerous situations and road traffic conflicts....
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Automatic road traffic safety management system in urban areas
PublicationTraffic incidents and accidents contribute to decreasing levels of transport system reliability and safety. Traffic management and emergency systems on the road, using, among others, automatic detection, video surveillance, communication technologies and institutional solutions improve the organization of the work of various departments involved in traffic and safety management. Automation of incident management helps to reduce...
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International architectural - urban - landscape design workshops to strengthen students’ education, capabilities and mobility
PublicationFive international architectural/urban/landscape workshops in Poland and Portugal between 2011 and 2015 are discussed in this article. The general aims of the workshops were to plan to connect divided city spaces, to harmonise them and make them attractive for different uses. The main task was to create in multicultural groups of students the vision of sustainable development in the context of architecture, urban and landscape...
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Cross-Bonding of MV Cable Lines for Energy Losses Decrease
PublicationCurrently, almost all medium voltage cable lines (MV) operate with the return wires earthed at both ends of the cable. Such a way of operation causes that during normal states of operation as well as during disturbances, e.g. short-circuits, in the return wires induce currents whose values mainly depend on the currents flowing in the phase wires. These currents in normal operating states are a source of additional energy losses...
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Domestic Wastewater Treatment
PublicationSSF systems are usually applied at the 2nd stage of domestic wastewater treatment, after mechanical treatment. The number of such installations working at the moment in Europe is estimated to be 100,000. In Germany about 10,000 systems are in operation.
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Pumps, Turbines and Small Hydropower, LEC/LAB, DaPE, sem.5 winter 2022/23 (M:320403W0)
e-Learning CoursesThe aim of the course is to identify and demonstrate knowledge of the major concepts, theoretical perspectives, and historical trends in small hydropower. This course examines the principles of sustainability and renewable energy conversion with emphasis on hydro energy resources. Concentration is placed on the relationships between the renewable resources, conversion technology and economic feasibility along with consideration...
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Pumps, Turbines and Small Hydropower, LEC/LAB, ET, sem.7 winter 2022/23 (PG_00042108)
e-Learning CoursesThe aim of the course is to identify and demonstrate knowledge of the major concepts, theoretical perspectives, and historical trends in small hydropower. This course examines the principles of sustainability and renewable energy conversion with emphasis on hydro energy resources. Concentration is placed on the relationships between the renewable resources, conversion technology and economic feasibility along with consideration...
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Pumps, Turbines and Small Hydropower, LEC/LAB, DaPE, sem.5 winter 2023/24 (M:320403W0)
e-Learning CoursesThe aim of the course is to identify and demonstrate knowledge of the major concepts, theoretical perspectives, and historical trends in small hydropower. This course examines the principles of sustainability and renewable energy conversion with emphasis on hydro energy resources. Concentration is placed on the relationships between the renewable resources, conversion technology and economic feasibility along with consideration...
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Pumps, Turbines and Small Hydropower, LEC/LAB, ET, sem.7 winter 2023/24 (PG_00042108)
e-Learning CoursesThe aim of the course is to identify and demonstrate knowledge of the major concepts, theoretical perspectives, and historical trends in small hydropower. This course examines the principles of sustainability and renewable energy conversion with emphasis on hydro energy resources. Concentration is placed on the relationships between the renewable resources, conversion technology and economic feasibility along with consideration...
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Indicators describing the effectiveness of tax systems of selected OECD countries
Open Research DataThe following research data include indicators describing the effectiveness of the tax administration activity in Poland compared to selected countries. In economic understanding efficiency is measured by the calculation of the expenditure of funds spent on its operation and performance of statutory functions. In this respect, the basic indicator is...
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Strucutral steel - tensile test results
Open Research DataModern floating structures such as ships, oil platforms and offshore wind towers are built mostly of structural steel. It is a material that is subject to requirements which, when met, allows the construction and safe operation of the structure throughout its entire work cycle. One of the basic criteria that a material must meet is its strength. The...
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The influence of SVC on the progress of voltage collapse
PublicationThe article presents the simulation concerning the cooperation of SVC circuit with a generative set in time, when of power system reaches low values which may lead to the fall-out of generator from the synchronous operation.
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In Situ Verification of Numerical Model of Water Hammer in Slurries
PublicationThis paper presents a numerical model of transient flow in a pressure slurry pipeline network with verification based on in situ measurements. The model, primarily verified in laboratory conditions, has been extended and applied to the case of a large and complex slurry pipeline network in Poland. In the model, the equivalent density concept was applied. In situ experiments were performed for various unsteady flow episodes, caused by...
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An Optimal Power Point Tracking Algorithm in a Solar PV Generation System
PublicationThe non-linearity in I-V characteristics of a PV panel requires to be operated at knee point to extract maximum power. In order to operate the panel at optimal point, maximum power point tracking (MPPT) algorithm is employed in the control structure. The main objective of MPP tracking is to keep the operation at knee point of I-V characteristics under varying condition of temperature and solar insolation. Under non uniform solar...
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Energy Systems Stations, W, ET, sem.7, zimowy 22/23 (PG_00042106)
e-Learning CoursesInternal combustion engines - principle of operation and classification. Heat balance of the engine. Uniform and combined propulsion systems.The main comonents of the propulsion system. Power plant efficiency and waste heat utilization. Cooling water system, lubricating oil system, fuel oil systeml, gaseos fuel system (LNG), compressed air system, exhaust gas system. Fittings and accessories of pipeline systems in the power plant....
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The voltage on bus bars of the main switchboard of the ferry electrical power system during a sea voyage
Open Research DataThe dataset is part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. The attached dataset contains the measurement results carried out onboard the ferry during a sea voyage.
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Voltage fluctuations on the main switchgear of the industrial power system supplying the rolling mill motors_part_2
Open Research DataThe dataset presents the voltage waveforms on the bus bars of the main switchgear of the industrial power network for the supply of rolling mills. The data was recorded during an experiment whose purpose was to determine a level of short-term and long-term flicker caused by voltage fluctuations. In the virtual application of flickermeter, a hardware...
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A New Geodetic Method of Examination of Geometrical Conditions of a Crane Bridge
PublicationSafety is one of the key aspects related to crane-based material transport. In order to ensure safe crane operation and material transport, it is necessary to meet certain geometrical conditions. The authors addressed the geometrical conditions of a crane bridge, a substantial crane component. The paper presents the method to compute displacement components of points on the top of a bridge crane relative to their design position....
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Water-lubricated stern tube bearing - experimental and theoretical investigations of thermal effects
PublicationThe paper presents research results of thermal phenomena accompanying operation of a water-lubricated stern tube bearing with axial grooves. Experimental tests revealed, that intensity of forced axial flow has strong influence on bush temperature. Numerical simulations focused on investigation of the thermal phenomena under operation of water-lubricated journal bearing showed, that restricted axial flow promotes backflow of the...