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Search results for: flow%20direction
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Energy losses in hydrostatic drive:Drive investigation method compatible with diagram of power increase opposite to the direction of power flow
PublicationEnergy losses and efficiency of drive motor must be presented as functions of physical quantities independent of losses in the motor. Such quantities are speed and load required by the driven device, changing in the drive operating field. Speed and load decide of the useful power and, in differentiated way, of kinds and values of losses in the motor. But energy losses and efficiency of drive motors are evaluated as functions of...
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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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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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Erosion under turbulent slurry flow: An experimental determination of particle impact angle, impact direction, and distribution thereof by image processing
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Flow Maps and Flow Patterns of R1233zd(E) in a Circular Minichannel at Low, Medium and High Values of Saturation Pressure
PublicationThere is a gap in knowledge regarding the flow pattern of low-boiling working fluids in the range of high saturation temperatures (above 120°C) and medium and high reduced pressures (0.5-0.9). Data are present in the literature for similar values of reduced pressures, but for lower values of saturation temperature. This is due to the existing refrigeration applications of these working fluids. At high values of reduced pressure,...
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Hydrostatic drives as safe and energy saving machines. The drive investigation method compatible diagram of power increase opposite to the direction of power flow
PublicationProjektanci i producenci napędu hydrostatycznego nie dysponują możliwością dokładnego określania jego sprawności energetycznej zmieniającej się szeroko w polu pracy napędzanego urządzenia a więc w pełnym zakresie zmiany prędkości i obciążenia silnika hydraulicznego oraz lepkości zastosowanego czynnika roboczego. Dotyczy to zarówno określania strat i sprawności maszyn wyporowych (pompy i silnika hydraulicznego) zastosowanych w układzie...
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A comprehensive survey on low-cost ECG acquisition systems: Advances on design specifications, challenges and future direction
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A comprehensive survey on low-cost ECG acquisition systems: Advances on design specifications, challenges and future direction
PublicationAvailability of low-cost, reliable, and portable Electrocardiography (ECG) devices is still very important in the medical world today. Despite the tremendous technological advancement, Cardiovascular Diseases (CVDs) remain a serious health burden claiming millions of lives on an annual basis globally. This is more prevalent in Low and Middle-Income Countries (LMICs) where there are huge financial instability and lack of critical...
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Distributed graph searching with a sense of direction
PublicationIn this work we consider the edge searching problem for vertex-weighted graphs with arbitrarily fast and invisible fugitive. The weight function w provides for each vertex v the minimum number of searchers required to guard v, i.e., the fugitive may not pass through v without being detected only if at least w(v) searchers are present at v. This problem is a generalization of the classical edge searching problem, in which one has...
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Measurements of electron scattering in the backward direction
PublicationPrzedstawiono wyniki badań rozproszenia elektronów na atomach i cząsteczkach przeprowadzonych w zakresie dużych kątów rozproszenia do 180o.
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The Courts Public image - The Desired Direction of Change
PublicationThis paper proposes to scientifically explore notions of court identity, principles of shaping a court system's image, and best practices in positive court image development relating to thhe courts in Poland
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Decolorization of organic dyes solution by atmospheric pressure glow discharge system working in a liquid flow-through mode
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Experimental Study of Flow Rate in Hydraulic Satellite Motor with the Rotating Case at a Low Constant Rotational Speed
PublicationIn this article was described the methodology for the experimental study of flows in the prototype of a satellite hydraulic motor with a rotating body. The experimental tests of the motor were carried out at a low constant rotational speed in a wide range of pressure drop in this motor. The constant rotational speed of the motor was kept by a worm gear. Based on the test results, the leakage characteristics in the flat gaps of...
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Direction-of-Arrival Estimation Methods in Interferometric Echo Sounding
PublicationNowadays, there are two leading sea sounding technologies: the multibeam echo sounder and the multiphase echo sounder (also known as phase-dierence side scan sonar or bathymetric side scan sonar). Both solutions have their advantages and disadvantages, and they can be perceived as complementary to each other. The article reviews the development of interferometric echo sounding array configurations and the various methods applied...
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Flow boiling intensification in minichannels by means of mechanical flow turbulising inserts
PublicationThe work presents the results of experimental investigation on heat transfer in minichannels. Refrigerant R123 was used as a test fluid. Single vertical silver tubes of 380 mm length and 2.3 mm diameter were examined with two variants of turbulising inserts. A wide range of parameters was considered, namely mass flux G=534-3011 kg/(m2s), heat flux qw=28.5-68.4 kW/m2, saturation temperature Tsat=23-86 stC and the full range of vapour...
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About nutrient liquid flow between potential flow and cartilage surface in bioreactor
PublicationW niniejszej pracy wyznaczony został przepływ cieczy odżywczej o właściwościach nienewtonowskich w cienkiej warstwie granicznej w pobliżu powierzchni komórek chrząstki (chondrocytu) podczas hodowli w bioreaktorze. Ruch cieczy w warstwie granicznej jest wywołany wydatkiem przepływu dostarczanej cieczy do bioreaktora. Ponadto prędkość przepływu cieczy w warstwie granicznej wokół hodowanych komórek chrząstki stawowej jest uzależniona...
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A Comparison of Simplified Two-dimensional Flow Models Exemplified by Water Flow in a Cavern
PublicationThe paper shows the results of a comparison of simplified models describing a two-dimensional water flow in the example of a water flow through a straight channel sector with a cavern. The following models were tested: the two-dimensional potential flow model, the Stokes model and the Navier-Stokes model. In order to solve the first two, the boundary element method was employed, whereas to solve the Navier-Stokes equations, the...
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Detection of the Incoming Sound Direction Employing MEMS Microphones and the DSP
PublicationA 3D acoustic vector sensor based on MEMS microphones and its application to road traffic monitoring is presented in the paper. The sensor is constructed from three pairs of digital MEMS microphones, mounted on the orthogonal axes. Signals obtained from the microphones are used to compute sound intensity vectors in each direction. With this data, it is possible to compute the horizontal and vertical angle of an incoming sound....
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The new method of settings the small fishes' backs in the desired direction
PublicationW artykule przeanalizowano znane sposoby ukierunkowywania małych ryb grzbietem w jedną stronę. Podano założenia nowego sposobu orientowania poprzecznego. Przedstawiono wstępną analizę teoretyczną orientowania poprzecznego opartego na wykorzystaniu pary równoległych, nachylonych do poziomu, współbieżnych, gładkich rolek. Przeprowadzono weryfikację doświadczalną nowego sposobu na przykładzie szprotów bałtyckich. Ze względu na wstępny...
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Experience-based Intelligence Augmentation with Decisional DNA: Upcoming direction
PublicationIntelligence amplification systems and technologies have gained significant interest from academia and industry during the past few decades. One of the main reasons behind this trend is the fact that most experts agree that truly intelligent artificial system is yet to be developed. The question increasing often asked is this: Is full replication of human intelligence desirable key aim in intelligence related technology and research?...
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Non-adiabatic Effects in Pressure Drop Calculations in Flow Boiling and Flow Condensation in Minichannels
PublicationConsiderations presented in the paper relate both to the case of flow boiling and flow condensation in conventional channels as well as small diameter ones. Authors devoted all the possible attention that the modeling presented is applicable to the whole range of quality variation in both cases of condensation and boiling. The form of two-phase flow multiplier, which is a major factor in modeling presented here, should be capable...
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Flow distribution and heat transfer in minigap and minichannel heat exchangers during flow boiling
PublicationThe topic of boiling heat transfer in miniscale geometries has focused the ever increasing interest of researchers in recent years. However, most of the works are related to mini- and microchannels and much less to minigaps. Meanwhile, minigaps allow for more comprehensive experimental studies, i.e. flow visualisations due to the flat, two-dimensional configuration of the flow. The results of the experimental investigations of...
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Flow Analysis of a Kaplan Turbine
PublicationThis monograph is a guide to a method of experimental and numerical flow investigations for Kaplan - type turbines. The numerical calculations were compared with the test results of the model Kaplan turbine. The tests were carried out on the model test rig in the Gdańsk University of Technology. The turbine has been thoroughly experimentally investigated, resulting in the identification of optimum setting combination of the stator...
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The lemniscate knowledge flow model
PublicationKnowledge is seen as one of the main resources for organizations providing knowledge-intensive services. Therefore, sharing and reusing are the main goals of modern knowledge management (KM) approach, driven by information and communication technologies (ICT). However, one can ask for the details in order to provide means and tools to design and deploy environment able to fulfil these two goals. We observed that occurred interactions...
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Membrane distillation with laminar flow
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Management of complexity and information flow
PublicationProblemy złożoności i zarządzania przepływem informacji. W rozdziale omówio-no podejście do modelowania systemów złożonych oraz zarządzania przepływeminformacji w takich systemach. Rozwiązania odniesiono do płaszczyzny elasty-cznego wytwarzania. Poruszono aspekty miękkiego modelowania w takich środo-wiskach.
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Cogenerative micro power plants - a new direction for development of power engineering?
PublicationW pracy przedstawiono rozważania dotyczące perspektywy mikrosiłowni domowych w gospodarce rozproszonej. Przedstawiono oryginalne kryterium doboru czynnika roboczego w mikrosiłowni oraz przedstawiono sprawności cieplne i egzergetyczne obiegów Clausiusa-Rankina realizujących pracę mikrosiłowni.
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Wideband Radio Direction Finder Implemented in Software Defined Radio Technology
PublicationIn the paper a wideband radio direction finder (RDF) implemented in software defined radio (SDR) technology and the results of hardware layer research, including developed antenna switching unit (ASU), are presented. The results of tests of the devices, which are the part of the software defined radio platform (SDRP), and antenna switching unit, confirmed the possibility of using selected components in the final solution.
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New direction of education on mechanical engineering faculty in gdansk university of technology
PublicationW artykule opisano szczegółowo kierunki kształcenia wprowadzone w ostatnich latach na Wydziale Mechanicznym Pol. Gd. Przedstawiono ofertę kształcenia na nowych kierunkach takich jak Mechatronika, Inżynieria Mechaniczno-Medyczna oraz Zarządzanie i Inżynieria Produkcji dla studiów stacjonarnych pierwszego stopnia. Opisano również własne doświadczenia w implementacji procesu Bolońskiego trójstopniowego kształcenia w systemie European...
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Direction-of-Arrival Estimation Using an ESPAR Antenna with Simplified Beam Steering
PublicationIn this paper, it has been shown, how electronically steerable parasitic array radiator (ESPAR) antenna, in which beam steering is done in a simple way, can be used for directionof- arrival (DoA) estimation of an unknown signal impinging the antenna. The concept is based on an ESPAR antenna having twelve parasitic elements, in which beam switching is realized by RF switches providing required loads to its parasitic elements. Numerical...
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Simple 2-D Direction-of-Arrival Estimation Using an ESPAR Antenna
PublicationIn this letter, it has been shown how an electronically steerable parasitic array radiator (ESPAR) antenna can be used for 2-D direction-of-arrival (DoA) estimation employing received signal strength (RSS) values only. The proposed approach relies on changes in RSS values recorded at the antenna output port observed for different vertical and horizontal directions, while antenna’s main beam sweeps 360° area around the ESPAR antenna. Based...
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A Highly Sensitive Planar Microwave Sensor for Detecting Direction and Angle of Rotation
PublicationThis article presents a technique based on a modified complementary split-ring resonator (CSRR) to detect angular displacement and direction of rotation with high resolution and sensitivity over a wide dynamic range. The proposed microwave planar sensor takes advantage of the asymmetry of the sensor geometry and measures the angle of rotation in terms of the change in the relative phase of the reflection coefficients. The sensor...
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High-order compact difference algorithm on half-staggered meshes for low Mach number flows
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Comparitive study of heat transfer and pressure drop during flow boiling and flow condensation in minichannels
PublicationIn the paper a method developed earlier by authors is applied to calculations of pressure drop and heat transfer coefficient for flow boiling and also flow condensation for some recent data collected from literature for such fluids as R404a, R600a, R290, R32,R134a, R1234yf and other. The modification of interface shear stresses between flow boiling and flow condensation in annular flow structure are considered through incorporation...
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Calculation method for flow boiling and flow condensation of R134a and R1234yf in conventional and small diameter channels
PublicationThe paper presents the results of calculations performed using the authors’ model to predict the heat transfer coefficient during flow boiling for two refrigerants R134a and R1234yf. The experimental data from various past studies have been collected and the calculations have been conducted for the full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house...
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EHD Flow Measured by 2D PIV in a Narrow Electrostatic Precipitator with Longitudinally-to-flow Wire Electrode
PublicationIn this paper, results of the electrohydrodynamic (EHD) flow patterns in two narrow ESPs with longitudinally-to-flow wire electrode are presented. 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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Effect of asymmetric fluid flow distribution on flow boiling in a microchannel heat sink – An experimental investigation
PublicationFlow boiling in microchannels is emerging as an exclusive cooling solution for miniaturized high-power electronic devices alongside having other high heat flux applications. Size miniaturization at microscale strangely increases heat transfer performance as well as flow boiling instabilities. Many flow boiling instabilities are interrelated and result from imperfect hydrodynamic conditions. One of such problems is flow maldistribution among...
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Channel Blockage and Flow Maldistribution during Unsteady Flow in a Model Microchannel Plate heat Exchanger
PublicationThis paper describes the problem of channel blockage as a result of flow maldistribution between the channels of a model mini channel plate heat exchanger consisting of one pass on each leg. Each leg of the heat exchanger contains 51 parallel and rectangular minichannels of four hydraulic diameters namely 461 μm, 571 μm, 750 μm and 823 μm. In addition, a more complex geometry has been investigated where for the sake of breaking...
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EXPERIMENTAL VERIFICATION OF THE METHOD OF FLOW BOILING AND FLOW CONDENSATION HEAT TRANSFER PREDICTION FOR SELECTED FLUIDS
PublicationIn the paper presented are the results of calculations using authors own model to predict heat transfer coefficient during flow boiling of different refrigerants. The experimental data from various research studies from literature were collected. Calculations were conducted for a full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in- house developed model....
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Application of Feed Forward Neural Networks for Modeling of Heat Transfer Coefficient During Flow Condensation for Low and High Values of Saturation Temperatur
PublicationMost of the literature models for condensation heat transfer prediction are based on specific experimental parameters and are not general in nature for applications to fluids and non-experimental thermodynamic conditions. Nearly all correlations are created to predict data in normal HVAC conditions below 40°C. High temperature heat pumps operate at much higher parameters. This paper aims to create a general model for the calculation...
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Experimental validation of pressure drop models during flow boiling of R134a – effect of flow acceleration and entrainment
PublicationA 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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Interaction Between Storm Water Conduit Flow and Overland Flow for Numerical Modelling of Urban Area Inundation
PublicationNowadays we can observe increasing frequency of inundations in cities. This makes accurate predicting of inundations more important than ever. Numerical modeling of this issue requires complex approach with simultaneous calculations of pipe flow and surface flow. In this paper, after a short review of known methods used for solving pipe and surface flow, we will try to answer the question if presented methods would be sufficiently...
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Rapid Antenna Optimization with Restricted Sensitivity Updates by Automated Dominant Direction Identification
PublicationMeticulous tuning of geometry parameters turns pivotal in improving performance of antenna systems. It is more and more often realized using formal optimization methods, which is demonstrably the most efficient way of handling multiple design variables, objectives, and constraints. Although in some cases a need for launching global search arises, a typical design scenario only requires local optimization, especially when a decent...
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Biomedical engineering of polysaccharide-based tissue adhesives: Recent advances and future direction
PublicationTissue adhesives have been widely used for preventing wound leaks, sever bleeding, as well as for enhancing drug delivery and biosensing. However, only a few among suggested platforms cover the circumstances required for high-adhesion strength and biocompatibility, without toxicity. Antibacterial properties, controllable degradation, encapsulation capacity, detectability by image-guided procedures and affordable price are also...
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Practical aspects of Flow Thinning optimization
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Complexity of a classical flow restoration problem
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Isotropic damage in viscoplastic flow conditions
PublicationMechanika zniszczenia jest obecnie jedną z ważniejszych gałęzi mechaniki ciał stałych. Jest cały czas rozwijającą się dziedziną nauki, która znalazła swoje zastosowania w problemach inżynierskich. W artykule zaprezentowano podstawowe informacje na temat lepkoplastyczności i jej zastosowania, koncepcję mechanicznej reprezentacji zniszczenia przez zmienną D, koncepcję naprężeń efektywnych, równania opisujące zniszczenie oraz lepkoplastyczny...
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Modelling of dryout process in an annular flow
PublicationW pracy pokazano teoretyczny model kryzysu wrzenia przy wysokich stopniach suchości, który jest modyfikacją modelu proponowanego wcześniej przez Sedlera i Mikielewicza. Model wysychania filmu cieczowego w przepływie pierścieniowym składa się z różniczkowych równań bilansu masy zapisanych dla filmu na ściance i kropel w rdzeniu przepływu. Rozwiązanie układu równań wymaga znajomości gęstości strumienia masy kropel wytrącających się...
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Dryout in annular flow - theoretical analysis
PublicationW pracy zaprezentowano model kryzysu wrzenia w przepływie pierścieniowym, obowiązujący dla wysokich wartości stopnia suchości i stanowiący modyfikację wcześniejszej wersji modelu zaproponowanego przez Sedlera i Mikielewicza. Model ten uwzględnia bilans masy w filmie cieczowym i bilans masy dla kropel cieczy w rdzeniu przepływu oraz zawiera dodatkowy człon odpowiedzialny za odparowanie filmu na ściance kanału. Rozwiązanie układu...
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Outlet Flow Velocity In Circular Culvert
PublicationThe outlet flow velocity in the end section of the culvert barrel depends in most cases on the culvert geometry, including the barrel slope, as well as on upstream and downstream channel parameters. Flowing water can create pressure flow or free surface flow in the culvert barrel. In the case of an unsubmerged barrel outlet, the free-surface flow is more frequent than the full flow. Increased velocities can cause channel bed scour...