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Search results for: multi-phase flows
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Explanation of Reduction of Pressure Forces in Turbine Chamber Seals
PublicationThe paper describes a chamber seal reducing the aerodynamic forces created in shroud seals. Asymmetrical pressure distribution (due to rotor-stator eccentricity) in the blade tip clearance leads to the creation of pressure forces acting on the blade shroud. By increasing the volume above the shroud, the pressure distribution becomes more uniform on the whole shroud circumference and the effect of rotor eccentricity is reduced....
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METROPOLITAN AREAS IN CENTRAL POLAND AND THEIR IMPACT ON MIGRATION FLOWS
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Design of Optical Wireless Networks with Fair Traffic Flows
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Theoretical investigations into flows in rotor blade shroud clearance
PublicationPrzedstawiono wyniki obliczeń programem Fluent przepływów w uszczelnieniu nadbandażowym stopnia turbinowego przy różnym mimośrodowym położeniu osi wirnika względem osi korpusu. Wyznaczone numerycznie rozkłady ciśnienia w uszczelnieniu i generowane tam siły aerodynamiczne porównano z rezultatem badań przeprowadzonych na powietrznej turbinie modelowej.
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Survivability of unicast and anycast flows under attacks on networks
PublicationW artykule zaproponowano nowy algorytm zwany RA zapewniania ochrony transmisji anycast przed atakami na sieci o topologii nieregularnej. Założono wykorzystanie pojedynczej ścieżki podstawowej chroniącej połączenie przed awarią pojedynczego węzła sieci. Serwery: podstawowy i zabezpieczający każdej transmisji anycast rozlokowano w odrębnych węzłach sieci. Zaproponowano: specjalną metrykę kosztu łączy służącą do wyznaczania ścieżek...
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On homotopy Conley index for multivalued flows in Hilbert spaces
PublicationPodano aproksymacyjną definicję indeksu homotopijnego, otrzymując naturalne związki z podobnymi niezmiennikami. Zbadano własności tego niezmiennika i zastosowano do badania gradientowych potoków wykazując pewne geometryczne własności zbiorów niezmienniczych
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PHASE OBJECT OBSERVATION SYSTEM BASED ON DIFFRACTION PHASE MICROSCOPY
PublicationIn the paper authors present a special measurement system for observing phase objects. The diffraction phas microscopy makes it possible to measure the dimensions of a tested object with a nanometre resolution. To meet this requirement, it is proposed to apply a spatial transform. The proposed setup can be based either on a two lenses system (called 4 f ) or a Wollaston prism. Both solutions with all construction aspects are described...
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Multi Queue Approach for Network Services Implemented for Multi Core CPUs
PublicationMultiple core processors have already became the dominant design for general purpose CPUs. Incarnations of this technology are present in solutions dedicated to such areas like computer graphics, signal processing and also computer networking. Since the key functionality of network core components is fast package servicing, multicore technology, due to multi tasking ability, seems useful to support packet processing. Dedicated...
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Low-Loss Mechanically Tunable Resonator and Phase Shifters in Groove Gap Waveguide Technology
PublicationThis research is focused on the design and realization of high-performance high-power variable phase shifters in groove gap waveguide technology. Specifically, it is shown that the unique characteristic of groove gap waveguides, which is its proper operation without the need for electrical connection between the top and bottom sections of the waveguide, can be used to design mechanically tunable devices. Using the proposed method,...
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Towards application of uncertainty quantification procedure combined with experimental procedure for assessment of the accuracy of the DEM approach dedicated for granular flow modeling
PublicationThere is a high demand for accurate and fast numerical models for dense granular flows found in many industrial applications. Nevertheless, before numerical model can be used its need to be always validated against experimental data. During the validation, it is important to consider how the measurement data sets, as well as the numerical models, are affected by errors and uncertainties. In this study, the uncertainty quantification...
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Prototype of an opto-capacitive probe for non-invasive sensing cerebrospinal fluid circulation
PublicationIn brain studies, the function of the cerebrospinal fluid (CSF) awakes growing interest, particularly related to studies of the glymphatic system in the brain, which is connected with the complex system of lymphatic vessels responsible for cleaning the tissues. The CSF is a clear, colourless liquid including water (H2O) approximately with a concentration of 99 %. In addition, it contains electrolytes, amino acids, glucose, and...
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COMPLEXITY OF INNOVATIVE FINANCIAL PRODUCTS: THE CASE OF SYNTHETIC EXCHANGE TRADED FUNDS IN EUROPE
PublicationThe aim of the text is the presentation of the most important categories of exchange traded funds (ETFs) – physical and synthetic ones. A theoretical part of the text includes an overview of the main features of ETFs, the presentation of differences between physical and synthetic funds and the main risks posed by both types to their users and the whole financial systems. An empirical part focuses on the European market. Time span...
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Multi-objective optimization of microextraction procedures
PublicationOptimization of extraction process requiresfinding acceptable conditions for many analytes and goodperformance in terms of process time or solvent consumption. These optimization criteria are oftencontradictory to each other, the performance of the system in given conditions is good for some criteriabut poor for others. Therefore, such problems require special assessment tools that allow to combinethese contradictory criteria into...
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Sensorless Disturbance Detection for Five Phase Induction Motor with Third Harmonic Injection
PublicationThe paper presents a sensorless disturbance detection procedure that was done on a five phase induction motor with third harmonic injection. A test bench was developed where a three phase machine serves as disturbance generator of different frequencies. The control of the machines is based on multi scalar variables that ensures an independent control of the motor EMF and the rotor flux. For disturbance identification a speed observer...
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Flows in turbine blade seals: CFD calculations versus experiment
PublicationPrzedstawiono wyniki numerycznej analizy przepływu w uszczelnieniu nadbandażowym stopnia turbinowego. Rezultaty obliczeń porównano z danymi doświadczalnymi. Eksperymenty przeprowadzono na modelowej turbinie powietrznej przy różnych częstościach obrotów wału i różnym obciążeniu turbiny.
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Joint optimization of anycast and unicast flows in survivable optical networks
PublicationZnane z literatury dotychczasowe prace związane z ochroną ruchu przed awarią elementów sieci dotyczą transmisji typu unicast (jeden-do-jednego). Niniejszy artykuł jest pierwszym prezentującym rozwiązanie jednoczesnej ochrony transmisji anycast (jeden-do-jednego-z-wielu) oraz transmisji unicast. Proponowane podejście wykorzystuje model ochrony ścieżki (ang. path protection). Zagadnienie zostało sformułowane w postaci odpowiedniego...
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CFD analysis of jet flows ejected from different nozzles
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DISTRIBUTION OF FLOWS IN A CHANNEL NETWORK UNDER STEADY FLOW CONDITIONS
PublicationThe article presents an algorithm for calculating the distribution of flow in a junction of open channel network under steady flow conditions. The article presents a simplified calculation algorithm used to estimate the distribution of flow in a network of channels under steady flow conditions. The presented algorithm is based on the continuity equation and a simplified energy equation. To describe the relationship between the...
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Smart Document-Centric Processing of Human Oriented Information Flows
PublicationUsually people prefer to focus on creative rather than repetitive and schematic work patterns. Still, they must spend a lot of time complying with the procedures, selecting the information they receive and repeatedly restoring the previous state of work. This paper proposes the Mobile INteractive Document architecture (MIND) - a document-centric uniform interface to provide both effective communication of content and coordination...
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Multi-task Video Enhancement for Dental Interventions
PublicationA microcamera firmly attached to a dental handpiece allows dentists to continuously monitor the progress of conservative dental procedures. Video enhancement in video-assisted dental interventions alleviates low-light, noise, blur, and camera handshakes that collectively degrade visual comfort. To this end, we introduce a novel deep network for multi-task video enhancement that enables macro-visualization of dental scenes. In particular,...
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Multi-DBD actuator with floating interelectrode for aerodynamic control
PublicationIn this paper the use of a floating inter-electrode in a multi-DBD (dielectric barrier discharge) plasma actuator is described. The multi-DBD plasma actuators with floating inter-electrodes were investigated to get a longer DBD on a dielectric surface and to maximise generated net airflow. Our actuator was used to control the boundary layer flow separation around NACA0012 airfoil model. The results of our investigations suggests...
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Shared multi-processor scheduling
PublicationWe study shared multi-processor scheduling problem where each job can be executed on its private processor and simultaneously on one of many processors shared by all jobs in order to reduce the job’s completion time due to processing time overlap. The total weighted overlap of all jobs is to be maximized. The problem models subcontracting scheduling in supply chains and divisible load scheduling in computing. We show that synchronized...
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POLDER AND CITY: SUSTAINING WATER LANDSCAPES ON AN URBAN EDGE
PublicationThe question investigated in this paper is how to maintain the environmental quality of the polder landscape encompassing the city in the condition of urban pressure on this landscape. On the basis of theoretical approaches, historical surveys and introductory study models new ideas are tested on the case study of Gdansk, a city located in the Vistula River delta in northern Poland. Research shows that the city was created as a...
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Impact of SDN Controller’s Performance on Quality of Service
PublicationSoftware Defined Networking is a paradigm in network architecture; that is quickly becoming commonplace in modern telecommunication systems. It facilitates network customization for the requirements of different applications and simplifies the implementation of new services. Since its proposal, a significant evolution in its functionality has occurred. However, this development brought along problems of efficiency and performance,...
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Providing Public Space Continuities in Post-Industrial Areas through Remodelling Land/Water Connections
PublicationThis article examines the problem of urban transformation strategies applied in recent years which are based on the creation of new water areas and modification of existing ones. The research is an attempt to prove that modifications of plans of water areas and forms of their borders may play an important role in achieving the best quality public spaces in post-industrial territories. The basis for demonstrating the importance...
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Reshaping financial systems: The role of ICT in the diffusion of financial innovations – Recent evidence from European countries
PublicationExchange-traded funds (ETFs) are among the fastest-growing types of innovative financial products. The emergence and spread of these instruments have been facilitated by the digital revolution. Information and communication technology (ICT) is profoundly reshaping the global economic landscape, laying solid foundations for unrestricted and unbounded flows of information and knowledge, eliminating information asymmetries, and furthering...
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The OptD-multi method in LiDAR processing
PublicationNew and constantly developing technology for acquiring spatial data, such as LiDAR (light detection and ranging), is a source for large volume of data. However, such amount of data is not always needed for developing the most popular LiDAR products: digital terrain model (DTM) or digital surface model. Therefore, in many cases, the number of contained points are reduced in the pre-processing stage. The degree of reduction is determined...
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Representation of magnetic hysteresis in single-phase transformer for circuit simulations
PublicationThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. In the circuit transformer model, it is assumed that there is a flux common Φ to all windings as nonlinear and hysteretic function of the total currents Θ (Ampere turns) of all windings. To simulate magnetic behaviour of the iron core the feedback scalar Preisach model of hysteresis is developed. The Preisach...
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Asynchronous phase-location system
PublicationThis paper presents concept and implementation of digital phase-location system, designed as a navigational aid for marine applications. The main feature of the proposed system is the ability to work in both synchronous mode, with one master station and set of slave stations synchronised with master, and in asynchronous mode with independent clocking of all stations.
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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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Multi-objective weather routing of sailing vessels
PublicationThe paper presents a multi-objective deterministic method of weather routing for sailing vessels. Depending on a particular purpose of sailboat weather routing, the presented method makes it possible to customize the criteria and constraints so as to fit a particular user’s needs. Apart from a typical shortest time criterion, safety and comfort can also be taken into account. Additionally, the method supports dynamic weather data:...
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Machine Learning in Multi-Agent Systems using Associative Arrays
PublicationIn this paper, a new machine learning algorithm for multi-agent systems is introduced. The algorithm is based on associative arrays, thus it becomes less complex and more efficient substitute of artificial neural networks and Bayesian networks, which is confirmed by performance measurements. Implementation of machine learning algorithm in multi-agent system for aided design of selected control systems allowed to improve the performance...
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Temperature distribution of supercapacitors prepared by various technologies
PublicationSupercapacitors, also known by different names such as electrostatic double-layer capacitors (EDLCs) or ultra-capacitors, are electrical storage devices still in development. These devices require fast and reliable methods of assessing their state-of-health. Thermographic imaging is a method which can be applied with this aim due to its popularity, and the high negative impact of overheating on a supercapacitor’s parameters. Moreover,...
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Sustainability of Cluster Organizations as Open Innovation Intermediaries
PublicationThe purpose of the paper is to identify the most important open innovation practices used by cluster organizations (COs). To reflect these practices, the paper uses the concept of the trajectory of relationship development in COs, applied in the Interizon cluster organization. Additionally, this paper introduces the potential sustainability-related implications of open innovation adoption in cluster organizations. An in-depth direct...
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Experiencing historic waterways and water landscapes of the Vistula River Delta
PublicationThe paper gives insights into the characteristics of Vistula River Delta water landscapes, referring to the process of creating land out of water by Polish, Dutch and German settlers. Based on this, the paper presents an integrated strategy formed upon studies in cultural geography and aesthetics, and focused on enhancing the unique characteristics of the region and its rediscovery by tourism. The long process of constructing Vistula...
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Marine traffic risk modelling – an innovative approach and a case study
PublicationThis paper presents a model to analyse the risk of two common marine accidents: collision and grounding. Attention is focused on oil tankers since they pose the highest environmental risks. A case study in selected areas of the Gulf of Finland in ice-free conditions is presented. The model utilizes a formula for risk calculation that considers both the probability of an unwanted event and its consequences. The model can be decomposed...
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Electromagnetic Control and Dynamics of Generalized Burgers’ Nanoliquid Flow Containing Motile Microorganisms with Cattaneo–Christov Relations: Galerkin Finite Element Mechanism
PublicationIn our research work, we have developed a model describing the characteristics of the bio-convection and moving microorganisms in the flows of a magnetized generalized Burgers’ nanoliquid with Fourier’s and Fick’s laws in a stretchable sheet. Considerations have been made to Cattaneo–Christov mass and heat diffusion theory. According to the Cattaneo–Christov relation, the Buongiorno phenomenon for the motion of a nanoliquid in...
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End-to-end packed delay distribution of flows using EF PHB.
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Research into flows in turbine blade seals. Part I: Research methods
PublicationOpisano numeryczną i doświadczalną metodę badania przepływu w uszczelnieniu nadbandażowym stopnia turbinowego. Badania numeryczne przeprowadzono programem Fluent, a badania doświadczalne wykonano na powietrznej turbinie modelowej. Zamieszczono przykładowe wyniki.
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Research into flows in turbine blade seals. Part II: Numerical analysis
PublicationPrzedstawiono wyniki badań numerycznych programem Fluent przepływów w uszczelnieniu nadbandażowym stopnia turbinowego. Badania wykonano przy zastosowaniu różnych typów siatek obliczeniowych, różnych rodzajów "zszywek" oraz różnych metod obliczeniowych (Mixing Plane, Sliding Mesh, Multiple ReferenceFrame).
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Miniaturized solid-phase extraction techniques
PublicationMore than 80% of analysis time is spent on sample collection and sample preparation, so sample preparation is a critical part of the analytical process. Traditionally, liquid-liquid extraction was developed and employed to screen for general unknowns. However, solid-phase extraction (SPE) is becoming highly popular as an alternative, due to its simplicity and economy in terms of time and solvent. This review summarizes the current...
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EVOLUTIONARY MULTI–OBJECTIVE WEATHER ROUTING OF SAILBOATS
PublicationThe paper presents a multi-objective method, which optimises the route of a sailboat. The presented method makes use of an evolutionary multi-objective (EMO) algorithm, which performs the optimisation according to three objective functions: total passage time, a sum of all course alterations made during the voyage and the average angle of heel. The last two of the objective functions reflect the navigator’s and passenger’s comfort,...
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New Polymeric Materials for Solid Phase Extraction
PublicationSolid phase extraction (SPE) is a popular sample preparation technique, which can be applied directly in gas–solid phase and liquid–solid phase, or indirectly to solid samples by using, e.g., thermodesorption with subsequent chromatographic analysis. Although SPE can be described as a physical extraction process involving a liquid phase and a solid phase, the increased use of packed sorbent formats seems to have led to a bias toward...
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THE PHASE SHIFTERS INFLUENCE ON THE POWER SYSTEM STABILITY
PublicationThe paper presents the effect of phase shifters as FACTS devices on the possibility of improving the angle stability. Presented results obtained by the dynamic simulation performed on the mathematical model of the three machine system cooperating with the 400 kV network. The generative blocks models include turbine models with their controllers and models of synchronous generators with their excitation systems and voltage regulation....
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Gaze tracking in multi-display environment
PublicationThis paper presents the basic ideas of eye and gaze tracking in multiple-display environment. The algorithm for display detection and identification is described as well as the rules for gaze interaction in multi display environment. The core of the method is to use special LED markers and eye and scene tracking glasses. Scene tracking camera registers markers position which is then represented as a cloud of points. Analyzing the...
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Simulation of the remanence influence on the transient states in a single-phase multiwinding transformer
PublicationThis paper presents the mathematical model of a single-phase multi-winding core type transformer taking into account magnetic hysteresis phenomenon based on the feedback Preisach model (FPM). The set of loop differential equations was developed for a K-th winding transformer model where the flux linkages of each winding includes flux Φ common to all windings as a function of magneto motive force Θ of all windings. The first purpose...
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Critical behaviour of the smectic A*–C* phase transition and electroclinic effect of ferroelectric liquid crystals with terphenyl rigid core
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Phase transition of a dimorphic fungus Penicillium marneffei
PublicationPenicillium marneffei is a pathogenic fungus that afflicts immunocompromised individuals who live or travel in Southeast Asia. This species is unique, because it is the only dimorphic member of the genus Penicillium. Dimorphism results from a process, termed phase transition, which is regulated by temperature of incubation. At room temperature, the fungus grows filamentously (mould phase), but at body temperature (37°C), a uninucleate...
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On phase equilibrium of an elastic liquid shell with wedge disclination
PublicationBased on the six-parameter shell theory we consider the phase equilibrium of a two-phase liquid membrane containing a wedge disclination. The considered problems are related to modelling of phase transitions in biological or lipid membranes. In order to capture the membrane behaviour we consider a special case of elastic shells which energy is invariant under major transformations of a reference configuration and can be treated...
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Automated Design of Linear Phase Filters
PublicationThis paper presents a fast technique for an automated design of microwave filters with linear phase. The proposed method exploits the cost function defined using the location of complex zeros and poles of the filter’s transfer and reflection function. The effectiveness of the proposed technique is presented with two illustrative examples.