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Wyniki wyszukiwania dla: WATER FLOW THROUGH THE POOLS
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Experimental investigations on condensation in flow of HFE-7100 in small diameter channels
PublikacjaIn the paper the authors present investigations of flow condensation with the use of the HFE-7100 as a working fluid. The original and new approach to removing the heat from the channel was applied. The research was carried out using a wide-range real time observations, e.g. using infrared camera and stroboscope microphotography. This paper presents the details of experiment as well as the influence of heat and flow parameters...
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Experimental validation of pressure drop models during flow boiling of R134a – effect of flow acceleration and entrainment
PublikacjaA crucial step to assure proficient work of power and process apparatus is their proper design. A wide array of those devices operates within boiling or condensation of the working fluid to benefit from high heat transfer rates. Two-phase flows are associated with high heat transfer coefficients because of the latent heat of evaporation and high turbulence level between the liquid and the solid surface. Predicting heat transfer...
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Discrete-continuous optimisation of an axial flow blood pump
PublikacjaThis paper presents results of discrete-continuous optimisation of an axial flow blood pump. Evolution Strategies (ES) are used as a global optimisation method in order to localise the optimal solution in relatively short time. The whole optimisation process is fully automated. This also applies to geometry modelling. Numerical simulations of the flow inside the pump is performed by means of the Reynolds-Average Navier-Stokes...
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Spatial Differences in the Chemical Composition of Surface Water in the Hornsund Fjord Area: A Statistical Analysis with A Focus on Local Pollution Sources
PublikacjaSurface catchments in Svalbard are sensitive to external pollution, and yet what is frequently considered external contamination may originate from local sources and natural processes. In this work, we analyze the chemical composition of surface waters in the catchments surrounding the Polish Polar Station in Svalbard, Hornsund fjord area. We have pooled unpublished and already published data describing surface water composition...
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Alternative Approach to Convolution Term of Viscoelasticity in Equations of Unsteady Pipe Flow
PublikacjaIn the paper the selected aspects concerning description of viscoelastic behavior of pipe walls during unsteady flow are analyzed. The alternative convolution expression of the viscoelastic term is presented and compared with the corresponding term referring to unsteady friction. Both approaches indicate similarities in the forms of impulse response functions and the parameter properties. The flow memory was introduced into convolution...
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Comparison of Traffic Flow Models with Real Traffic Data Based on a Quantitative Assessment
PublikacjaThe fundamental relationship of traffic flow and bivariate relations between speed and flow, speed and density, and flow and density are of great importance in transportation engineering. Fundamental relationship models may be applied to assess and forecast traffic conditions at uninterrupted traffic flow facilities. The objective of the article was to analyze and compare existing models of the fundamental relationship. To that...
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Investigation of Liquid–Gas Flow in a Horizontal Pipeline Using Gamma-Ray Technique and Modified Cross-Correlation
PublikacjaThis article presents the application of the radioisotope absorption method in the study of two-phase water–air flow in a horizontal pipe. The measurement principle and the test stand are briefly described. The main part of the article presents the signal analysis methods applied to data obtained from scintillation detectors. Because these signals are mostly stochastic waveforms, they were analyzed statistically using the cross-correlation...
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Simplified Numerical Model for Transient Flow of Slurries at Low Concentration
PublikacjaRapid transients are particularly dangerous in industrial hydro-transport systems, where solid-liquid mixtures are transported via long pressure pipelines. A mathematical description of such flow is difficult due to the complexity of phenomena and difficulties in determining parameters. The main aim of the study was to examine the influence of the simplified mixture density and wave celerity description on satisfactory reproduction...
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Pollutants removal effectiveness in hydrophyte filters with sequential vertical and horizontal flow
PublikacjaThe object of investigations was the constructed wetland in Wiedersberg in Saxonia in Germany supplied with domestic sewage from 145 inhabitants. The biological part was composed of sequential reed beds with vertical and horizontal flow of sewage. It in one of new solutions, because up till now configuration with vertical bed situated at front of biological part of treatment was applied.The evaluation of object performance was...
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A New Approach for the Mitigating of Flow Maldistribution in Parallel Microchannel Heat Sink
PublikacjaThe problem of flow maldistribution is very critical in microchannel heat sinks (MCHS). It induces temperature nonuniformity, which may ultimately lead to the breakdown of associated system. In the present communication, a novel approach for the mitigation of flow maldistribution problem in parallel MCHS has been proposed using variable width microchannels. Numerical simulation of copper made parallel MCHS consisting of 25 channels...
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Investigation on water infiltration and water content changes in a large-scale experimental test dike
PublikacjaThe paper presents result of series of experiments made within the DREDGDIKES project, performed on a test dike built from composite soil. The composite is produced by mixing fly ash (by-product of energetics) with dredged material (sand) taken from the mouth of The Vistula river. The test dike, located near Gdansk in Poland, was subjected to hydraulic load in several flooding time scenarios and the unsaturated unsteady flow was...
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Hysteresis curves for some periodic and aperiodic perturbations in magnetosonic flow
PublikacjaA thermodynamic relation between perturbations of pressure and mass density in the magnetohydrodynamic flow is theoretically studied. Planar magnetohydrodynamic perturbations with the wave vector, which forms a constant angle with the equilibrium magnetic field, are under study. The theory considers thermal conduction of a plasma and the deviation from adiabaticity of a flow due to some kind of heating–cooling function. It also...
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Cylindrical orifice testing in laminar flow with the orifice diameter ratio β = 0.5
PublikacjaThe paper presents the results of an experimental study of a cylindrical orifice with the orifice diameter ratio β = 0.5 and the flow opening length‑to‑diameter ratio L/d = 1, with hydraulic oil flowing in the DN50 measuring channel. The measurements of the values characterising the oil flow were made in the laminar flow regime, for the Reynolds numbers ranging between Re = 100 to 950. Based on the experimental tests, standard...
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Methods of measurement signal acquisition from the rotational flow meter for frequency analysis
PublikacjaOne of the simplest and commonly used instruments for measuring the flow of homogeneous substances is the rotational flow meter. The main part of such a device is a rotor (vane or screw) rotating at a speed which is the function of the fluid or gas flow rate. A pulse signal with a frequency proportional to the speed of the rotor is obtained at the sensor output. For measurements in dynamic conditions, a variable interval between...
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Factors affecting the quality of bottled water
PublikacjaThe ever-increasing popularity of bottled water means that it is important to analyze not only its mineral content but also, above all,its content of possible contaminants, especially the organic ones. In this respect, bottled waters are a special case, because apartfrom organic chemical contaminants derived from the well from which they were acquired, their secondary contamination is alwayspossible, during treatment or storage...
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2022 Water treatment for consumption and industrial purposes
Kursy Online -
Dedicated scheduling of tasks to minimize mean flow time
PublikacjaThis paper investigates the complexity of scheduling biprocessor tasks on dedicated processors to minimize mean flow time. Since the general problem is strongly NP-hard, we assume some restrictions on task lengths and the structure of associated scheduling graphs. Of particular interest are acyclic graphs. In this way we identify a borderline between NP-hard and polynomially solvable special cases.
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Desalination of geothermal water by membrane distillation
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The Influent Effects of Flow Rate Profile on thePerformance of Microbial Fuel Cells Model
PublikacjaThe energy contained in wastewaters has been identified as a promising sustainableenergy resource that could be harvested by using microbial fuel cells (MFC). When dealing with realwastewaters, the MFCs should be able to manage high flow rates and flow rates fluctuations. In thiswork, the short-term effects of the influent flow rate variations on the performance of a microbialfuel cell has been studied. With this aim, the influent...
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Determination of pressure drop in flow condensation of HFE7000 in minichannels with account of non-adiabatic effects
PublikacjaFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena involving the change of phase. There is a temptation to describe both these phenomena with one only correlation, however such method has yet to be suggested. From amongst the structures present in flow boiling and flow condensation at least the annular flow structure seems to be mostly appropriate to the common modeling. However, the shear...
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Experimental investigations on pressure drop during the condensation in flow of HFE7000 in vertical minichannel
PublikacjaIn the work presented in the paper authors focused attention on the issues of flow resistance and pressure drop during condensation in the flow. The case of the descending flow through a cylindrical single-channel of 2.3 mm inner diameter was carefully analyzed. In the course of investigations a new working fluid HFE 7000 has been scrutinised which has a strongly differing properties in comparison to the other fluids that are commonly...
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Estimating the uncertainty of the liquid mass flow using the orifice plate
PublikacjaThe article presents estimation of measurement uncertainty of a liquid mass flow using the orifice plate. This subject is essential because of the widespread use of this type of flow meters, which renders not only the quantitative estimation but also qualitative results of this type so those measurements are important. To achieve this goal, the authors of the paper propose to use the theory of uncertainty. The article shows the...
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Design of horizontal axis wind and water turbines
PublikacjaThe basic hydrodynamic principles of horizontal axis turbines are presented. Computational methods based on vortex theory for design of such turbines and for calculation of their hydro or aerodynamic characteristics are described in detail. These methods are applicable both to wind and water turbines. The influence of detailed turbine geometry on its characteristics is presented. Several practical computational examples of different...
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Analysis of the process of water entry of an amphibious vehicle
PublikacjaThe paper presents a method of computational and experimental analysis of the process of water entry of an amphibious vehicle. The computational method is based on the Reynolds Averaged Navier-Stokes Equations (RANSE) solver and the xperiment was carried out in the towing tank at Ship Design and Research Centre S.A. with the use of a scale model. The analysis was focused on the safety of water entry, i.e. the maximum pitch and...
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Microbiological analysis of sea water and bottom sediments in Kosakowo – Gdańsk profile
Dane BadawczeThis dataset contains the results of microbiological analysis of sea water and bottom sediments in Kosakowo – Gdańsk profile in 2013 - 2014 . The tested material consisted of water samples (surface water and bottom water) and bottom sediment samples. Water and sediment samples were analysed for the following: number of Enterobacteriaceae genus bacteria,...
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Photolytic and Photocatalytic Recreational Water Treatment
PublikacjaDisinfection is one of the most important steps during recreational water treatment. Nevertheless, disinfection by-products are formed by conventional disinfectants, which pose several health threats. The concentration of disinfection by-products can be decreased by photolytic and photocatalytic treatment. Medium-pressure mercury lamp, UV-LEDs and solar irradiation were investigated and evaluated considering emitted wavelength,...
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Multi-Objective Water Distribution Systems Control of Pumping Cost, Water Quality, and Storage-Reliability Constraints
PublikacjaThis 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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Proton transfer reactions for ionized water clusters
PublikacjaCalculations of formation energies of the ionized water clusters and energies of reactions between small (including less than eight water molecules) neutral and positively ionized water clusters are presented. Moreover, we discuss some reaction paths between neutral and positively charged dimers, trimers and tetramers and proton transfer reactions (PTR) between cyclic clusters and H3O+ ions which can appear in beam experiments...
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WATER RESOURCES RESEARCH
Czasopisma -
PRESSURE DROP OF HFE7000 AND HFE7100 IN FLOW CONDENSATION IN MINICHANNELS WITH ACCOUNT OF NON-ADIABATIC EFFECTS
PublikacjaFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena involving the change of phase. There is a temptation to describe both these phenomena with one only correlation. From amongst the structures present in flow boiling and flow condensation at least the annular flow structure seems to be mostly appropriate to the common modeling. However, the shear stress acting between vapor phase and liquid...
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Effect of Flow Normalization in Micro-Pin-Finned Heat Sink: Numerical Study
PublikacjaThe micro-pin-fin heat sink (MPFHS) is widely employed for the heat transfer enhancement of microchannel heat sinks. In the current paper, the effect of flow normalization on the thermohydraulic performance of micro-pin-finned heat sinks is studied numerically. Two geometries of MPFHSs, the conventional design micro-pin-fin heat sink (CD-MPFHS) with a uniform-width micro pin fin and the proposed design micro-pin-fin heat sink (PD-MPFHS)...
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A simplified energy dissipation based model of heat transfer for post-dryout flow boiling
Publikacjamodel for post dryout mist flow heat transfer is presented based on considerations of energy dissipation in the flow. The model is an extension of authors own model developed earlier for saturated and subcooled flow boiling. In the former version of the model the heat transfer coefficient for the liquid singlephase convection as a reference was used, due to the lack of the appropriate model for heat transfer coefficient for the...
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MODEL FOR MEASUREMENT OF FLOW INSTALLATION TIME IN SDN SWITCH
PublikacjaSDN is the approach in telecommunication networks that separates control plane from data forwarding plane by specifying a single network entity as a controller that defines rules (called flows) of traffic forwarding for the switches connected to it. The time that is required for installation of these rules might be a hindrance for the overall performance of SDN network. In the paper, a model for testing and evaluating the influence...
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Vortex flow caused by periodic and aperiodic sound in a relaxing maxwell fluid
PublikacjaThis paper concerns the description of vortex flow generated by periodic and aperiodic sound in relaxing Maxwell fluid. The analysis is based on governing equation of vorticity mode, which is a result of decomposition of the hydrodynamic equations for fluid flow with relaxation and thermal conductivity into acoustical and non-acoustical parts. The equation governing vorticity mode uses only instantaneous, not averaged over sound...
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Signatures and acoustic images of objects moving in water
PublikacjaObservation of underwater space is part of a generaltrend, which primary purpose is to protect and increasesafety in the selected area. The basic aim of the paper ispresentation of designated acoustic characteristics typicalfor objects moving on the water surface and under water,which represent some knowledge about detection of theseobjects. Create a catalog of acoustic signature and not onlyacoustic, as well as acoustic images...
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On design and analysis of flow characteristics of the last stage of gas-steam turbine
PublikacjaResearch regarding blade design and analysis of flow have been conducted for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics (CFD) and computational flow mechanics (CFM). Currently a combination of mentioned methods is used for design of turbine blades. These methods enabled us to improve flow efficiency...
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Comparison of Average Energy Slope Estimation Formulas for One-dimensional Steady Gradually Varied Flow
PublikacjaTo 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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Analysis of latency between quotations and capital flow in capital markets.
PublikacjaThe aim of this paper is to prove that the derivative of the log of capital flow understood as price times volume advances the derivative of log of the price. A certain concept of signal processing using linear filtering has been proposed to conduct the research.
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A SHORT REVIEW OF BLOOD FLOW MODELLING METHODS: FROM MACRO- TO MICROSCALES
PublikacjaThe aim of this paper it to review various scale approaches to the blood flow modelling. Blood motion may be described by three types of mathematical models according to the observed scales or resolutions, namely microscopic, mesoscopic and macroscopic descriptions. The above approaches are discussed together with their advantages and disadvantages. Several results of mesoscopic simulations are presented with particular attention...
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EHD Flow Measured by 2D PIV in a Narrow Electrostatic Precipitator with Longitudinal Wire Electrode
PublikacjaIn this paper, results of the electrohydrodynamic (EHD) flow patterns in two narrow ESPs with longitudinally-to-flow wire electrode arepresented. The influence of the ESP geometry on the EHD flow generated in the ESP was investigated. The results obtained from 2-dimensional(2D) Particle Image Velocimetry (PIV) showed similarities and differences of the particle flow in the wire-plate and wire-cylinder type ESP.
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Investigating the Impact of Weather Conditions and Time of Day on Traffic Flow Characteristics
PublikacjaAdverse weather such as rain, snow, and fog may significantly reduce visibility or change adhesion properties and, as a consequence, affect drivers’ sense of safety, driving comfort, and their reaction to a changing driving environment (i.e., lower speed and increased headways). The changed behavior of individual drivers affects both traffic flow characteristics, that is, average speed and headways, and parameters related to highway...
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OBTAINING FLUID FLOW PATTERN FOR TURBINE STAGE WITH NEURAL MODEL.
PublikacjaIn the paper possibility of applying neural model to obtaining patterns of proper operation for fluid flow in turbine stage for fluid-flow diagnostics is discussed. Main differences between Computational Fluid Dynamics (CFD) solvers and neural model is given, also limitations and advantages of both are considered. Time of calculations of both methods was given, also possibilities of shortening that time with preserving the accuracy...
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Research on causes of corrosion in the municipal water supply system
PublikacjaThis paper presents results of failure analysis study to characterize the corrosion damage that occurred in the water supply system in Krakow. This analysis includes: electrochemical noise, linear polarization and resistometric measurements. Water aggressiveness of four water intakes was defined using Langelier and Ryznar indices. Results from this indices did not reveal the causes of considerable corrosion losses in water systems....
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ECG measurement in the bathtub - sitting on measuring electrodes, drl in water - men
Dane BadawczeThe measurement data shows the measurement of the ECG signal in water in the bathtub. The data includes the measurement time, the reference ECG signal from the chest, and the ECG signal measured by electrodes placed in the bathtub without contact with the human body. Using the presented data, it is possible to estimate the optimal arrangement of measuring...
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A simplified energy dissipation based model of heat transfer for subcooled flow boiling
PublikacjaIn the paper a model is presented based on energetic considerations for subcooled flow boiling heat transfer. The model is the extension of authors own model developed earlier for saturated flow boiling and condensation. In the former version of the model we used the heat transfer coefficient for the liquid single-phase as a reference level, due to the lack of the appropriate model for heat transfer coefficient for the subcooled...
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Modeling of entrained flow steam gasification of sewage sludge
PublikacjaProper management of sewage sludge becomes increasingly problematic due to legal requirements aiming at diminishing environmental impact, as well as rationalizing the utilization from the point of view of logistics. Steam gasification of sewage sludge can result in very good quality of the producer gas. So far, the works have been focused on the gasification in fixed bed gasifiers. However, this does not allow to take full advantage...
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Turbulence model evaluation for numerical modelling of turbulent flow and heat transfer of nanofluids
PublikacjaIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (Reynolds number between 6000 and 12000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
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Determination of organophosphorus and organonitrogen pesticides in water samples
PublikacjaPesticides are among the most dangerous environmental pollutants because of their stability, mobility and long-term effects on living organisms. Their presence in sources of drinking water, essential to life, is a particular danger. In water, these compounds can undergo transformations, leading to the production of substances of even greater toxicity. Legal regulations are in force, stipulating the highest permissible level of...
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Determination of the substances potentially allergenic in water
PublikacjaPersonal care chemicals are continuously released into environment through domestic and industrial wastewater, causing adverse effects on human health. Their presence can be detected in different environmental compartments. A group of chemicals included in most personal care products are the allergen fragrances. In the present work, simple and rapid methodology based on ultrasound-assisted emulsification-microextraction (USAEME)...
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Modelling hydraulic and capillary-driven two-phase fluid flow in unsaturated concretes at the meso-scale with a unique coupled DEM-CFD technique
PublikacjaThe goal of the research was to demonstrate the impact of thin porous interfacial transition zones (ITZs) between aggregates and cement matrix on fluid flow in unsaturated concrete caused by hydraulic/capillary pressure. To demonstrate this impact, a novel coupled approach to simulate the two-phase (water and moist air) flow of hydraulically and capillary-driven fluid in unsaturated concrete was developed. By merging the discrete...