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Search results for: improvable flows
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FE studies of quasi-static mass flow in bins: the polar elasto-plastic approach
PublicationPrzedstawiono wyniki numerycznej analizy zachowania się materiału sypkiego w silosie podczas przepływu quasi-statycznego. Obliczenia wykonano metodą elementów skończonych na bazie mikropolarnego sprężysto-plastycznego prawa materiałowego.
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The influence of the spatial distribution of leads and ice floes on the atmospheric boundary layer over fragmented sea ice
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Sizes and Shapes of Sea Ice Floes Broken by Waves–A Case Study From the East Antarctic Coast
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EVALUATION OF LIQUID-GAS FLOW IN PIPELINE USING GAMMA-RAY ABSORPTION TECHNIQUE AND ADVANCED SIGNAL PROCESSING
PublicationLiquid-gas flows in pipelines appear in many industrial processes, e.g. in the nuclear, mining, and oil industry. The gamma-absorption technique is one of the methods that can be successfully applied to study such flows. This paper presents the use of thegamma-absorption method to determine the water-air flow parameters in a horizontal pipeline. Three flow types were studied in this work: plug, transitional plug-bubble,...
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Use of radiography images and gray level co-occurrence matrix to investigate gravitational granular flow
PublicationThe paper presents analysis of granular gravitational flow based on radiography images processing. The investigations were conducted for silo model geometry with concentric/eccentric discharging modes. The continuous X-ray radiography scans of granular material distribution, acquired during flow, were obtained by means of an especially designed model silo with rectangular bin and different settings of hopper angles. Image processing...
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High-quality Experiment Dedicated to microGravity Exploration, Heat Flow and Oscillation Measurement from Gdańsk
PublicationIn this paper we propose HEDGEHOG (High-quality Experiment Dedicated to microGravity Exploration, Heat flow and Oscillation measurement from Gdańsk) REXUS experiment to investigate vibrational and heat flow phenomena during the whole (ascent, microgravity phase, descent and recovery) flight of a sounding rocket. First, a proposed system of cantilever beams is discussed to study dynamic behaviour of dummy payload. Dimensioning has...
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ANALYSIS OF THE IMPACT OF MASS FLOW EXTRACTION ON THE CHANGE OF PARAMETERS IN A LABYRINTH SEAL USING THE STODOLA METHOD
PublicationLabyrinth seals are an important element of a steam turbine set design. The use of diagnostic extraction makes it possible to control the operation of a seal by providing information on the thermodynamic parameters along the length of the seal. Diagnostic extraction has a considerable impact on the change of the parameters, the amount of the extracted mass. This article describes the dependence of pressure in the clearance downstream...
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Modeling of the Two-Dimensional Flow Caused by Sea Conditions and Wind Stresses on the Example of Dead Vistula
PublicationThe article presents the results of two-dimensional modeling of flows caused by the sea conditions and wind stresses on the example of Dead Vistula. Based on the available bathymetric data, a numerical model of the river section was created, which was supplemented with data on the position of the water table depending on hydrometeorological conditions. To describe the flow field in steady conditions, a simplified model of two-dimensional...
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Electrochemical degradation of textile dyes in a flow reactor: effect of operating conditions and dyes chemical structure
PublicationIn this study, electrochemical oxidation of five azo dyestuffs (Yellow D-5GN, Red D-B8, Ruby F-2B, Blue D-5RN, Black DN), that are widely used in the textile industry, was investigated in a flow reactor. BDD electrode with a high boron doping level (C/B = 10 000) was prepared and used. Two configurations of reactor were considered, i.e., one with the undivided cell, and the other with the cell divided by anodic and cathodic compartments....
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Electrohydrodynamic Flow Patterns in a Narrow Electrostatic Precipitator with Longitudinal Wire Electrode for Various Electrode Geometries
PublicationRecently narrow electrostatic precipitators (ESPs) have become a subject of interest because of their possible application in diesel engines. In this paper results of 2-dimensional (2D) Particle Image Velocimetry (PIV) measurements of the flow patterns in a narrow ESP for a various electrode geometries are presented. The PIV measurements were carried out in the observation plane that is perpendicular to the ESP duct. The ESP was...
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A semi-empirical method for calculation of heat transfer coefficient in flow boiling for conventional tubes and minichannels
PublicationW pracy przedstawiono zagadnienia które należy uwzględnić podczas modelowania wymiany ciepła z wrzeniem w przepływie w kanałach o małej średnicy. Uzyskano dobrą zgodność z wynikami badań eksperymentalnych.
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Static renewal and continuous-flow calibration of two types of passive samplers for the monitoring of pharmaceuticals in wastewater
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Acute Effects of Different Blood Flow Restriction Protocols on Bar Velocity During the Squat Exercise
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Acute impact of blood flow restriction on strength-endurance performance during the bench press exercise
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Method of determination of the reticulocyte age distribution from flow cytometry count by a structured-population model
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Reactions of NO2 with chromium(III) complexes with histamine and pyridoxamine ligands studied by the stopped-flow technique
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Determination of paraffin oil mist penetration at high flow rates through air-purifying respirators
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Heat transfer to car engine cooling system - influence of coolant flow through engine block
PublicationW artykule przedstawiono wyniki badań doświadczalnych nad wpływem nastawianej wydajności pompy cieczy na strumień odbieranego ciepła w silniku spalinowym. Wykorzystano hamownię silnikową z silnikiem o zapłonie iskrowym o objętości skokowej 1.8 dm^3. Przyjęto obciążenia silnika oporami ruchu samochodu na biegu bezpośrednim.
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Influence of Analyte Flow Rate on Signal and Response Time of the Amperometric Gas Sensor with Nafion Membrane
PublicationW publikacji przedstawiono rezultaty badań nad wpływem zmian objętościowego natężenia przepływu gazu na sygnał i czas odpowiedzi prototypowego czujnika ditlenku siarki z membraną nafionową. Porównywano właściwości czujników różniących się materiałem elektrody pracującej oraz składem roztworu elektrolitu wewnętrznego. Zastosowano elektrody pracujące wykonane z napylonych próżniowo na powierzchnię membrany nafionowej złota i platyny....
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A new method for determination of flow boiling heat transfer coefficient in conventional diameter channels and minichannels
PublicationW pracy przedstawiono rozważania związane z modelowaniem wrzenia w przepływie w kanałach o średnicach konwencjonalnych, małych i minikanałach. Przedstawiono przegląd podejść do modelowania wymiany ciepła i w tym świetle przedstawiono oryginalne podejście autora. W przeciwieństwie do innych podejść metoda autora ma zastosowanie zarówno do kanałów o średnicach konwencjonalnych i minikanałach. Przedstawiono zadowalające porównania...
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Visualizing the macroscale spatial distributions of biofilms in complex flow channels using industrial computed tomography
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Nowe podejście do gwarancji QoS w sieciach IP - Flow Aware Networking (FAN)
PublicationArtykuł przedstawia nowy sposób gwarantowania jakości w sieciach IP zaproponowany przez dział R&D France Telecom. W oparciu o istotne cechy ruchu internetowego opisane zostały problemy napotykane przez dotychczasowe architektury QoS. Przybliżono założenia FAN oraz przykład praktycznej implementacji - ruter Cross-protect. FAN realizuje gwarancje QoS poprzez sterowanie przyjęciem do obsługi oparte o przepływy i pomiary ruchu na...
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Implicit versus explicit finite volume schemes for extreme, free surface water flow modelling.
PublicationPrzedstawiono jeden jawny i trzy niejawne schematy metody objętości skończonych. Porównano własności tych schematów oraz oceniono możliwości ich stosowania do modelowania gwałtownych przepływów w kanałach otwartych. Zaproponowano modyfikację schematu niejawnego. Poprawiony schemat może być stosowany do obliczeń przepływu szybkozmiennego w kanałach otwartych i w sieciach kanalizacyjnych.
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Comparison of Average Energy Slope Estimation Formulas for One-dimensional Steady Gradually Varied Flow
PublicationTo find the steady flow water surface profile, it is possible to use Bernoulli’s equation, which is a discrete form of the differential energy equation. Such an approach requires the average energy slope between cross-sections to be estimated. In the literature, many methods are proposed for estimating the average energy slope in this case, such as the arithmetic mean, resulting in the standard step method, the harmonic mean and...
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Analytical-numerical approach to solve the transport equation for steady gradually varied flow in open channel
PublicationW pracy przedstawiono metodę rozwiązania równania transportu adwekcyjno-dyfuzyjnego w przypadku ustalonego niejednostajnego przepływu w kanałach otwartych. Metoda wykorzystuje technikę dekompozycji. Do rozwiązania równania adwekcji-dyfuzji zastosowano analityczne rozwiązanie w postaci odpowiedzi impulsowej liniowego równania adwekcji-dyfuzji. Dokonano adaptacji metody dla przypadku ze zmiennymi parametrami. Do rozwiązania drugiej...
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A semi-empirical method for calculation of heat transfer coefficient in flow boiling for conventional tubes and minichannels
PublicationW pracy przedstawiono zagadnienia któe należy uwzględnić podczas modelowania wymiany ciepła z wrzeniem w przepływie w kanałach o małej średnicy. Uzyskano dobrą zgodność z wynikami badań eksperymentalnych.
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Influence of gas parameters alteration on the form of gas-flow-impact appearing in long transportation pipelines
PublicationPrzy szybkich zamknięciach przepływu w długich liniach transportowych gazu, obserwuje się znaczne przesterowania ciśnienia, towarzyszące zjawiskom udarowym, wywołane zarówno falą uderzeniową jak i odbitą. Głównym czynnikiem wpływającym na postać fali uderzeniowej i jej amplitudy, jest szybkość zamykania zaworu odcinającego określona stałą czasową serwomotoru sterującego zaworem. Ponieważ obserwuje się zmiany właściwości chemicznych...
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Experimental and numerical simulations of flow and heat transfer in heatexchanger elements using liquid crystal thermography.
PublicationPrzedstawienie koncepcji badań eksperymentalnych i numerycznych oraz ich wyników podczas wymiany ciepła w modelach klasycznych i płytowych wymienników ciepła w warunków przepływów przejściowych i turbulentnych.
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Nitrogen removal in vertical flow constructed wetlands: influence of bed depth and high nitrogen loadings
PublicationThe aim of the study was to evaluate the nitrogen removal and its effects on the plant’s growth and leaves morphology. using two subsurface vertical flow (VF bed), with different depths (0.24 m2 × 0.70 m; 0.24 m2 × 0.35 m) and nitrogen load increments. The VF bed were planted with Vetiveria zizanioides, filled with light expanded clay aggregates (Leca®NR 10/20) and fed in parallel mode with synthetic wastewater. High ammonium nitrogen...
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Electrohydrodynamic secondary flow and particle collection efficiency in spike-plate multi-electrode electrostatic precipitator
PublicationIn this work the results of electrohydrodynamic (EHD) secondary flow measurements in a spike-plate type electrostatic precipitator (ESP) are presented. In the investigated ESP two-sided and one-sided spike electrodes were used as a discharge electrodes. The results of 2D PIV measurements showed that flow pattern obtained for a different spike tips positions in respect to the primary flow direction significantly changing the flow...
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Electrohydrodynamic Secondary Flow and Particle Collection Efficiency in Spike-Plate Multi-Electrode Electrostatic Precipitator
PublicationIn this work the results of electrohydrodynamic (EHD) secondary flowmeasurements in a spike-plate type electrostatic precipitator (ESP) are presented. In the investigated ESP two-sided and one-sided spike electrodes were used as a discharge electrodes. The results of 2D PIVmeasurements showed that flow pattern obtained for a different spike tips positions in respect to the primary flow direction significantly changing the flow...
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Spectroscopic study of atmospheric pressure 915 MHz microwave plasma at high argon flow rate
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Balance errors generated by numerical diffusion in the solution of non-linear open channel flow equations
PublicationThe paper concerns the untypical aspect of application of the dissipative numerical methods to solve nonlinear hyperbolic partial differential equations used in open channel hydraulics. It is shown that in some cases the numerical diffusion generated by the applied method of solution produces not only inaccurate solution but as well as a balance error. This error may occur even for an equation written in the conservative form not...
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Partitioning of heavy metals in sub-surface flow treatment wetlands receiving high-strength wastewater
PublicationThe 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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Neural network simulator's application to reference performance determination of turbine blading in the heat-flow diagnostics.
PublicationIn the paper, the possibility of application of artificial neural networks to perform the fluid flow calculations through both damaged and undamaged turbine blading was investigated. Preliminary results are presented and show the potentiality of further development of the method for the purpose of heat-flow diagnostics.
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Fully Separated Flow Control Using DBD Plasma Actuators Located at the Leading Edge of an Airfoil
PublicationIn the framework of the PLASMAERO European project, experiments were conducted to investigate the authority of surface DBD plasma actuators to alter a fully separated flow around an airfoil in order to improve its aerodynamic performances in its natural stall regime. In this paper, unsteady excitation control is more specifically investigated. The key control parameter studied here is the burst frequency which periodically imposes...
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Spectroscopic study of atmospheric pressure 915 MHz microwave plasma at high argon flow rate
PublicationIn this paper results of optical emission spectroscopic (OES) study of atmospheric pressure microwave 915 MHz argon plasma are presented. The plasma was generated in microwave plasma source (MPS) cavity- resonant type. The aim of research was determination of electron excitation temperature Texc gas temperature Tg and electron number density ne. All experimental tests were performed with a gas flow rate of 100 and 200 l/min and...
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Electrohydrodynamic flow and particle collection efficiency in a one-sided spike-plate type electrostatic precipitator
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ANALYSIS OF THE IMPACT OF MASS FLOW EXTRACTION ON THE CHANGE OF PARAMETERS IN A LABYRINTH SEAL USING THE STODOLA METHOD
PublicationLabyrinth seals are an important element of a steam turbine set design. The use of diagnostic extraction makes it possible to control the operation of a seal by providing information on the thermodynamic parameters along the length of the seal. Diagnostic extraction has a considerable impact on the change of the parameters, the amount of the extracted mass. This article describes the dependence of pressure in the clearance downstream...
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Extraction and evaluation of gas-flow-dependent features from dynamic measurements of gas sensors array
PublicationGas analyzers based on gas sensors are the devices which enable recognition of various kinds of volatile compounds. They have continuously been developed and investigated for over three decades, however there are still limitations which slow down the implementation of those devices in many applications. For example, the main drawbacks are the lack of selectivity, sensitivity...
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Impact of Energy Slope Averaging Methods on Numerical Solution of 1D Steady Gradually Varied Flow
PublicationIn this paper, energy slope averaging in the one-dimensional steady gradually varied flow model is considered. For this purpose, different methods of averaging the energy slope between cross-sections are used. The most popular are arithmetic, geometric, harmonic and hydraulic means. However, from the formal viewpoint, the application of different averaging formulas results in different numerical integration formulas. This study...
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Time Delay Estimation in Two-Phase Flow Investigation Using the γ-Ray Attenuation Technique.
PublicationTime delay estimation is an important research question having many applications in a range of technologies. Measurement of a two-phase flow in a pipeline or an open channel using radioisotopes is an example of such application. For instance, the determination of velocity of dispersed phase in that case is based on estimation of the time delay between two stochastic signals provided by scintillation probes. The proper analysis...
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Experimental investigations on adiabatic frictional pressure drops of R134a during flow in 5mm diameter channel
PublicationThe article presents detailed two-phase adiabatic pressure drops data for refrigerant R134a at a saturation pressure of 5.5 bar corresponding to the saturation temperature of 19.4 °C. Study cases have been set for a mass flux varying from 100 to 500 kg/m2 s. The frictional pressure drop was characterized for the refrigerant R134a, for vapor qualities ranging from 0 to 1. Long-time thermal stability of test facility allowed to gather...
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Temperature Impact of Nitrogen Transformation in Technological System: Vertical Flow Constructed Wetland and Polishing Pond
PublicationThe article describes the results of the research, purpose of which was to evaluate influence of the temperature on the effectiveness of nitrification and denitrification in the sewage treatment system consisting of vertical flow constructed wetland and polishing pond. During the analysed period, the efficiency of removing total nitrogen was low and amounted to 12.7%. In the polishing pond in the summer period, content of total...
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The description of non-linear interactions of wave and non-wave modes in a non-adiabatic plasma flow
PublicationThe method of derivation of non-linear equations for interacting modes is explained and applied to a plasma's flow affected by a magnetic field. It is based on the linear projecting of the total perturbation field into specific variations of variables in individual modes of a flow. The method may be applied in many examples of fluid flows with different mechanisms of non-adiabaticity. It is of special importance in complex flows...
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Flow cytometric approach to evaluate the impact of hydro-technical concrete compounds’ release to the freshwater microbiome
PublicationThe aim of this research was to test the potential of applying a flow cytometric procedure to evaluate the impact of concrete compounds’ release to the freshwater microbiome. Cells from the collected samples were stained with a fluorogenic redox indicator dye that measures the redox potential of microbial cells. This novel approach was combined with the assessment of microorganisms’ penetration into the internal structures of concrete...
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Computational Fluid Dynamics Simulation of Gas–Liquid Multiphase Flow in T-junction for CO2 Separation
PublicationThe article presents the results of a computational fluid dynamics (CFD) analysis of gas-liquid multiphase flow. The simulation was conducted using CFD code and the Euler–Euler approach. The presented study relates to the non–reactive, steady-state, turbulent flow of water and carbon dioxide mixture in a 3D pipe. Separation phenomenon between phases is observed. The solution was obtained using a mixture model. Different values...
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Analytical ‘Steady-State’-Based Derivation and Clarification of the Courant-Friedrichs-Lewy Condition for Pipe Flow
PublicationThis article addresses the problem of choosing the optimal discretization grid for emulating fluid flow through a pipeline. The aggregated basic flow model is linearized near the operating point obtained from the steady state analytic solution of the differential equations under consideration. Based on this model, the relationship between the Courant number (μ) and the stability margin is examined. The numerically set coefficient...
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Evolution of electrohydrodynamic flow of sduspended particles in a needle-to-plate negative DC corona discharge in air
PublicationCorona discharges are used for collecting dust in electrostatic precipitators (ESPs). The dust collection is mainlyrealized by the electric forces which move the ionized dust particles to the collecting electrodes. However, the presence of coronadischarge in the space between the charging and collecting electrodes in ESPs causes also the so-called ionic wind which set the gasmolecules and dust...
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Study of Non-Newtonian biomagnetic blood flow in a stenosed bifurcated artery having elastic walls
PublicationFluid structure interaction (FSI) gained attention of researchers and scientist due to its applications in science felds like biomedical engineering, mechanical engineering etc. One of the major application in FSI is to study elastic wall behavior of stenotic arteries. In this paper we discussed an incompressible Non-Newtonian blood fow analysis in an elastic bifurcated artery. A magnetic feld is applied along x direction. For...