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Search results for: FLUID FLOW MEASUREMENT
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Frequency measurement research with weight averaging of pulse output signal of voltage-to-frequency converter
PublicationThe paper presents the essence and investigation of the efficiency of weight averaging of a pulse output signal of voltage-to-frequency converter. The effect of counting and the influence of interference on the result of weight averaging of frequency modulated pulses are analyzed. It is shown that from the point of view of counting error reduction, the best are polynomial weight functions. In the case of high interferences whose...
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Discrete-continuous optimisation of an axial flow blood pump
PublicationThis 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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Measurement of sub-nanometer molecular layers with ISFET without a reference electrode dependency
PublicationA new method of detection and measurement with sub-nanometer resolution of layers adsorbed or bonded to the ISFET's gate dielectric was presented. The sensitivity of this method is high enough to detect even partial mono-layer covering. The transconductance measurement of the ISFET provides independence of the output signal from pH changes and the driving electrode electrochemical potential instabilities. The stable reference electrode...
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Alternative Approach to Convolution Term of Viscoelasticity in Equations of Unsteady Pipe Flow
PublicationIn 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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Computational issues of solving the 1D steady gradually varied flow equation
PublicationIn this paper a problem of multiple solutions of steady gradually varied flow equation in the form of the ordinary differential energy equation is discussed from the viewpoint of its numerical solution. Using the Lipschitz theorem dealing with the uniqueness of solution of an initial value problem for the ordinary differential equation it was shown that the steady gradually varied flow equation can have more than one solution....
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Double Bias of Mistakes: Essence, Consequences, and Measurement Method
PublicationThere is no learning without mistakes. However, there is a clash between‘positive attitudes and beliefs’regarding learning processes and the ‘negative attitudes and beliefs’towardthese being accompanied bymistakes. Thisclash exposesa cognitive bias towardmistakesthat might block personal and organizational learning. This study presents an advanced measurement method to assess thebias of mistakes. The essence of it is the...
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Evaluation of the fast impedance spectroscopy method in the laboratory measurement system
PublicationIn this paper the method for fast impedancespectroscopy of technical objects with very high impedance(|Zx| ≥ 1 GΩ) is evaluated by means of simulation and practicalexperiment. The method is based on excitation of an object, witha square pulse and measurements of voltage and currentresponses with DAQ card. The object impedance spectrum isobtained with use of continuous Fourier transform. Someimprovements of the method concerned...
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Comparison of Traffic Flow Models with Real Traffic Data Based on a Quantitative Assessment
PublicationThe 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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The Concept of Geodetic Analyses of the Measurement Results Obtained by Hydrostatic Leveling
PublicationThe article discusses the issue of hydrostatic leveling. Its application is presented in structural health monitoring systems in order to determine vertical displacements of controlled points. Moreover, the article includes a complete computation scheme that utilizes the estimation from observation differences, allowing the elimination of the influence of individual sensors’ systematic errors. The authors suggest two concepts of...
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Simplified Numerical Model for Transient Flow of Slurries at Low Concentration
PublicationRapid 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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Generation of the vorticity Mode by Sound in a Relaxing Maxwell Fluid
PublicationPraca dotyczy nowej teorii akustyki nieliniowej badającej związki modu akustycznego z modem wirowym w płynach z relaksacją maxwellowską. Wyprowadzone zostało równanie ewolucyjne dla modu wirowego wywołanego dźwiękiem, które można stosować zarówno do dźwięków okresowych, jak i aperiodycznych. Przedstawiono przykłady generacji modu wirowego w płynie maxwellowskim z relaksacją wywołanego okresową i aperiodyczną falą dźwiękową.
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Acoustic heating produced in resonators filled by a newtonian fluid
PublicationAcoustic heating in resonators is studied. The governing equation of acoustic heating is derived by means of the special linear combination of conservation equations in differential form, allowing the reduction of all acoustic terms in the linear part of the final equation, but preserving terms belonging to the thermal mode responsible for heating. This equation is instantaneous and includes nonlinear acoustic terms that form a...
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mRNA profiling for vaginal fluid and menstrual blood identification
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Lubricity-based estimation of the changes in the brake fluid quality
PublicationW artykule przedstawiono, na podstawie wyników badań laboratoryjnych, możliwość określenia wartości smarności łączącej własności fizykochemiczne i reologiczne płynów. Smarność, która została określona dla trzech płynów hamulcowych (oznaczenia zastrzeżone przez firmę zlecającą porównanie ich własności), umożliwiła wybór najlepszego, który pewnie zostanie zastosowany w instalacjach hamulcowych samochodów.
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Pollutants removal effectiveness in hydrophyte filters with sequential vertical and horizontal flow
PublicationThe 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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Hysteresis curves for some periodic and aperiodic perturbations in magnetosonic flow
PublicationA 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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On the differential effect of temperature on the Nusselt-Rayleigh relationship in free convection
PublicationThe aim of and inspiration behind this paper was to explain the reasons, also observed by other researchers, of the discrepancy in the results of experimental free convection, which for small Rayleigh and Nusselt numbers in the initial phase of research can sometimes reach several hundred percent. These discrepancies decrease with increasing heating power and plate surface temperature, in proportion to the increase in Ra and Nu,...
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Cylindrical orifice testing in laminar flow with the orifice diameter ratio β = 0.5
PublicationThe 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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Measurement of Impulse Response of Shallow Water Communication Channel by Correlation Method
PublicationPerformances of underwater acoustic communication (UAC) systems are strongly related to specific propagation conditions of the underwater channel; conditions that can additionally change in time due to the movement of the acoustic system transmitter and receiver or to reflection by underwater objects of the transmitted signal. The time-varying impulse response is a comprehensive description of dynamically changing transmission...
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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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Fault Loop Impedance Measurement in Circuits Fed by UPS and Principle of Safety Protection
PublicationThis paper indicates a significant problem of uncertainty of fault loop impedance (FLI) measurement in circuits powered from uninterruptible power supply (UPS) (double-conversion AC-DC-AC). The correctly determined value of this impedance, related to the short-circuit current disconnection time and to the reference value, is one of the most important elements that determines the approval of an electrical installation and its receivers...
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Dedicated scheduling of tasks to minimize mean flow time
PublicationThis 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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The Influence of Camera and Optical System Parameters on the Uncertainty of Object Location Measurement in Vision Systems
PublicationThe article presents the influence of the camera and its optical system on the uncertainty of object position measurement in vision systems. The aim of the article is to present the methodology for estimating the combined standard uncertainty of measuring the object position with a vision camera treated as a measuring device. The identification of factors affecting the location measurement uncertainty and the determination of their...
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Determination of the tram track axis using a multi receiver GNSS measurement system
PublicationThis article refers to research, that has been conducted by an interdisciplinary research team from the Gdańsk University of Technology and the Maritime University in Gdynia since 2009. These investigation concerns the determination of a railway track axis using the mobile satellite measurement technique. Following the dynamic development of GNSS techniques, that could be seen in the last decade, the team carried out further experiments...
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Simulations of air and water flow in a model dike during overflow experiments
PublicationFlow in flood dikes, earth dams, and embankments occurs in variably saturated conditions, with pores of the earth material filled partly with water and partly with air. In routine engineering analysis, the influence of pore air is neglected and the air pressure is assumed equal to atmospheric. In some circumstances, for example, during overtopping of the dike by water, the effect of pore air on water flow and stability of the structure...
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The Influent Effects of Flow Rate Profile on thePerformance of Microbial Fuel Cells Model
PublicationThe 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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Sounding Mechanism of a Flue Organ Pipe—A Multi-Sensor Measurement Approach
PublicationThis work presents an approach that integrates the results of measuring, analyzing, and modeling air flow phenomena driven by pressurized air in a flue organ pipe. The investigation concerns a Bourdon organ pipe. Measurements are performed in an anechoic chamber using the Cartesian robot equipped with a 3D acoustic vector sensor (AVS) that acquires both acoustic pressure and air particle velocity. Also, a high-speed camera is employed...
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Ellipse-fitting algorithm implementation in the impedance measurement system based on DAQ card with FPGA
PublicationThe paper presents an implementation of the ellipse-fitting algorithm in the impedance measurement system based on DAQ card equipped with FPGA chip. The method implementation was tested by simulation means as well as experimentally in the designed and presented measurement system. Finally, the limit values of sampling parameters which assures satisfying accuracy were given.
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Determination of pressure drop in flow condensation of HFE7000 in minichannels with account of non-adiabatic effects
PublicationFlow 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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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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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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Time-domain description of point-source acoustic wavefields as a useful approach in ultrasonic techniques
PublicationIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
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Structural properties of foil bearings: a closed-form solution validated with finite element analysis
PublicationFluid film thickness in a compliant foil bearing is greatly influenced by the deflection of the bearing structure. Therefore, in order to properly model performance of a foil bearing, it is mandatory that the deflection of the compliant bearing structure due to the generated hydrodynamic pressure is determined accurately. This article proposes an easy-to-use two-dimensional model, which takes into account detailed geometry of the...
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Time-Domain Description of Point-Source Acoustic Wavefields as a Useful Approach in Ultrasonic Techniques
PublicationIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
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Local Nusselt number evaluation in the case of jet impingement
PublicationJet impingement still is one of demanding cases regarding computational fluid dynamics, due to its highly turbulent behaviour, with occurrence of turbulent-laminar transition. Even recently developed methods exhibit some drawbacks – RANS based simulations lack accuracy, LES and DNS based ones require too much computational time. Hybrid methods also exist, but their development and validation is in progress. Nevertheless, CFD application...
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Bone healing under different lay‐up configuration of carbon fiber‐reinforced PEEK composite plates
PublicationSecondary healing of fractured bones requires an application of an appropriate fixa-tor. In general, steel or titanium devices are used mostly. However, in recent years,composite structures arise as an attractive alternative due to high strength to weightratio and other advantages like, for example, radiolucency. According to Food andDrug Administration (FDA), the only unidirectionally reinforced composite allowed tobe implanted...
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Human subarachnoid space width oscillations in the resting state
PublicationAbnormal cerebrospinal fluid (CSF) pulsatility has been implicated in patients suffering from various diseases, including multiple sclerosis and hypertension. CSF pulsatility results in subarachnoid space (SAS) width changes, which can be measured with near-infrared transillumination backscattering sounding (NIR-T/BSS). The aim of this study was to combine NIR-T/BSS and wavelet analysis methods to characterise the dynamics of the...
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Rheology of Variable Viscosity‐Based Mixed Convective Inclined Magnetized Cross Nanofluid with Varying Thermal Conductivity
PublicationCross nanofluid possesses an extraordinary quality among the various fluidic models to explore the key characteristics of flowing fluid during very low and very high shear rates and its viscosity models depend upon shear rate. The current study establishes the numerical treatment regarding variable viscosity‐based mixed convective inclined magnetized Cross nanofluid with var‐ ying thermal conductivities over the moving permeable...
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Molecular dynamics simulations of the affinity of chitin and chitosan for collagen: the effect of pH and the presence of sodium and calcium cations
PublicationChitosan and chitin are promising biopolymers used in many areas including biomedical applications, such as tissue engineering and viscosupplementation. Chitosan shares similar properties with hyaluronan, a natural component of synovial fluid, making it a good candidate for joint disease treatment. The structural and energetic consequences of intermolecular interactions are crucial for understanding the biolubrication phenomenon...
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Water-Lubricated Journal Bearings Marine Applications, Design, and Operational Problems and Solutions
PublicationWater-Lubricated Journal Bearings: Marine Applications, Design, and Operational Problems and Solutions provides cutting-edge design solutions, common problems and methods for avoiding them, and material selection considerations for the use of water-lubricated journal bearings in marine environments. These bearings have many advantages, including the absence of the potential for oil contamination. They are also sensitive, and their...
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Impact of thermal backfill parameters on current-carrying capacity of power cables installed in the ground
PublicationProper design of power installations with the participation of power cables buried in homogeneous and thermally well-conductive ground does not constitute a major problem. The situation changes when the ground is non-homogeneous and thermally low-conductive. In such a situation, a thermal backfill near the cables is commonly used. The optimization of thermal backfill parameters to achieve the highest possible current-carrying capacity...
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The Effect of Sodium Tetrafluoroborate on the Properties of Conversion Coatings Formed on the AZ91D Magnesium Alloy by Plasma Electrolytic Oxidation
PublicationMagnesium and its alloys are widely used in many areas because of their light weight, excellent dimensional stability, and high strength-to-weight ratio. However, the material exhibits poor wear and corrosion resistance, which limits its use. Plasma electrolytic oxidation (PEO) is an effective surface modification method for producing ceramic oxide layers on Mg and their alloys. The influence of the additions of sodium tetrafluoroborate...
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Performance of DS-CDMA Radionavigation Receiver with Subsample Time Measurement Resolution in Various Environments
PublicationThis paper presents results of investigation of position estimation performance in TDOA radionavigation system with receiver containing code tracking loop with subsample time measurement resolution. Position estimation accuracy was evaluated using real signals from CDMA base stations, recorded during measurement campaigns in various environments: on sea, flat terrain and hilly terrain.
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A Thermographic Measurement Approach to Assess Supercapacitor Electrical Performances
PublicationThis paper describes a proposal for the qualitative assessment of condition of supercapacitors based on the conducted thermographic measurements. The presented measurement stand was accompanied by the concept of methodology of performing tests. Necessary conditions, which were needed to minimize the influence of disturbing factors on the performance of thermal imaging measurements, were also indicated. Mentioned factors resulted...
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LOW COST MEASUREMENT MODULE FOR MATRIX OF AMPEROMETRIC GAS SENSOR
PublicationThis paper describes an amperometric sensor module for gas concentration measurement. A module can be used for many types of electrochemical gas sensors without major hardware changes. Device is based on AVR ATmega8 microcontroller. As signal processing circuit a specialized integrated circuit LMP9l000 configurable via I2C interface is used. The concept of a measuring system composed of several modules dedicated for a gas sensors...
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A simplified energy dissipation based model of heat transfer for post-dryout flow boiling
Publicationmodel 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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Effect of Flow Normalization in Micro-Pin-Finned Heat Sink: Numerical Study
PublicationThe 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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Low-power device simulator for micro-energy measurement methods testing
PublicationThe paper presents low-power device simulator designed for testing of micro-energy measurement methods. Such kind methods can be used for evaluation of power systems based on Energy Harvesting. The device allows to set the current consumption characteristic over the time, thus making possible playing the role of different types of low-power devices e.g. simulating sensor network node.
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Analysis of latency between quotations and capital flow in capital markets.
PublicationThe 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
PublicationThe 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...