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Wyniki wyszukiwania dla: energy losses
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Method of sum of power losses as a way for determining the ki coefficients of energy losses in hydraulic motor
PublikacjaThis paper shows application of the method of sum of power losses to determining energy losses which occur in hydraulic rotary motor in situation when not all laboratory data are at one’s disposal or when no use is made of data contained in catalogue charts. The method makes it possible to determine the coefficients ,ki , of energy losses occurring in the motor. The method of sum of power losses is based on the approach proposed...
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Cross-Bonding of MV Cable Lines for Energy Losses Decrease
PublikacjaCurrently, almost all medium voltage cable lines (MV) operate with the return wires earthed at both ends of the cable. Such a way of operation causes that during normal states of operation as well as during disturbances, e.g. short-circuits, in the return wires induce currents whose values mainly depend on the currents flowing in the phase wires. These currents in normal operating states are a source of additional energy losses...
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Energy Losses Due to Imperfect Payment Infrastructure and Payment Instruments
PublikacjaOne of the strategic objectives of the European Union is a reduction in greenhouse gas emissions and improvement of energy efficiency by at least 32.5% in different areas of the economy by 2030. However, little is known about the impact of payment in retail on energy consumption. The purpose of this paper is to assess the chain of losses of time and energy, and therefore financial losses, that occur due to the imperfection of payment...
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Energy losses reduction in the medium voltage cable line – case study
PublikacjaThe paper presents an analysis of energy losses in a power cable system, which is composed of two 30 kV cable lines. This cable system is located at the seaside holiday area, so the load profile during a year is specific. Energy losses related to reactive power transmission, as well as to currents induced in the sheaths of the cables, are subject to analysis. Measurements were made in the system in order to prepare a computer model...
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Losses and energy efficiency of drive motors and systems
PublikacjaLosses and energy efficiency of every 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 machine or device driven by the motor, changing in the drive operating field. Speed and load of the motor decide of the instantaneous useful power of the motor and also in a differentiated way of kinds and values of losses occurring in the...
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Losses and energy efficiency of drive motors and systems
PublikacjaLosses and energy efficiency of every 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 machine or device driven by the motor, changing in the drive operating field. Speed and load of the motor decide of the instantaneous useful power of the motor and also in a differentiated way of kinds and values of losses occurring in the...
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Energy losses in the hydraulic rotational motor - definitions and relations for evaluation of the efficiency of motor and hydrostatic drive
PublikacjaStosowane dotychczas w badaniach naukowych i w praktyce przemysłowej metody oceny strat i sprawności energetycznej obrotowych silników hydraulicznych stosowanych w napędach hydrostatycznych dają błędne rezultaty, ponieważ obarczone są wpływem samych strat na parametry, w funkcji których straty i sprawności są oceniane.Celem pracy było zdefiniowanie w silniku parametrów pracy, rozwijanych mocy, występujących strat i sprawności energetycznej...
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Effect of the working liquid compressibility on the picture of volumetric and mechanical losses in a high pressure displacement pump used in a hydrostatic drive. Part I Energy losses in a drive system, volumetric losses in a pump
PublikacjaŚciśliwość cieczy roboczej może znacząco zmienić wartości i proporcje współczynników strat objętościowych i mechanicznych w pompie wyporowej zastosowanej w układzie napędu hydrostatycznego. Wpływ ten jest szczególnie widoczny w trakcie pracy pod wysokim ciśnieniem a także wówczas, gdy występuje zapowietrzenie cieczy roboczej. W części I przedstawiono wykres zaproponowany przez autora, wzrostu mocy w układzie napędu hydrostatycznego...
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Effect of the working liquid compressibility on the picture of volumetric and mechanical losses in a high pressure displacement pump used in a hydrostatic drive. Part I Energy losses in a drive system, volumetric losses in a pump
PublikacjaŚciśliwość cieczy roboczej może znacząco zmienić wartości i proporcje współczynników strat objętościowych i mechanicznych w pompie wyporowej zastosowanej w układzie napędu hydrostatycznego. Wpływ ten jest szczególnie widoczny w trakcie pracy pod wysokim ciśnieniem a także wówczas, gdy występuje zapowietrzenie cieczy roboczej. W części I przedstawiono wykres zaproponowany przez autora, wzrostu mocy w układzie napędu hydrostatycznego...
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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
PublikacjaEnergy 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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Comparison of the powers of energy losses in a variable capacity displacement pump determined without or with taking into account the power of hydraulic oil compression
PublikacjaPowers of energy losses in a variable capacity displacement pump are compared with or without taking into account the power of hydraulic oil compression. Evaluation of power of liquid compression in the pump was made possible by the use of method, proposed by the Author, of determining the degree of liquid aeration in the pump. In the method of determining the liquid aeration in the pump and of powers of volumetric losses of liquid...
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Review of hydrogen production technologies for automotive sector – thermodynamic analysis of energy and exergy losses
PublikacjaFew recent years has shown that hydrogen technology has a good chance to replace petroleum technology in automotive sector. However, hydrogen in pure form practically does not occur on Earth. That is why H2 form is used only as an energy carrier and it must be produced using another source of energy form water or hydrocarbon fuels. In this paper short overview of hydrogen production technology has been presented, with energy and...
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Graphical presentation of the power of energy losses and power developed in the elements of hydrostatic drive and control system. Part I. Rotational hydraulic motor speed series throttling control systems
PublikacjaZaproponowano i uzasadniono wykres przedstawiający kierunek wzrostu strumienia mocy narastającej od wału lub tłoczyska silnika hydraulicznego do wału pomopy, mocy narastającej w wyniku wymuszania przez moce strat energetycznych występujących w elementach układu i sterowania hydrostatycznego. Przedstawiono interpretację graficzną mocy strat energetycznych występujących w elementach układów, a także mocy rozwijanych przez te elementy....
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Graphical presentation of the power of energy losses and power developed in the elements hydrostatic drive and control system. Part II. Rotational hydraulic motor speed parallel throtling control and volumetric control systems
PublikacjaPrzedstawiono interpretację graficzną mocy strat energetycznych występujących w elementach układów napędu i sterowania hydrostatycznego, a także mocy rozwijanych przez te elementy. Dokonano analizy układu indywidualnego ze sterowaniem dławieniowym równoległym prędkości silnika hydraulicznego obrotowego, układu indywidualnego ze sterowaniem objętościowym, pompą o zmiennej wydajności, prędkości silnika hydrailicznego obrotowego,...
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Exergy Losses in the Szewalski Binary Vapor Cycle
PublikacjaIn this publication, we present an energy and exergy analysis of the Szewalski binary vapor cycle based on a model of a supercritical steam power plant. We used energy analysis to conduct a preliminary optimization of the cycle. Exergy loss analysis was employed to perform a comparison of heat-transfer processes, which are essential for hierarchical cycles. The Szewalski binary vapor cycle consists of a steam cycle bottomed with...
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MEASUREMENT AND ANALYSIS OF TRANSMISSION LOSSES IN THE SUPPLY SYSTEM OF ELECTRIFIED TRANSPORT
PublikacjaThe issue of electric energy saving in public transport is currently becoming a key area of interest, a fact connected with both an increase in society’s environmental awareness and a rise in the prices of fuel and electricity. Electricity can be saved by reducing transmission losses in the supply system. The article presents a method of measurement and analysis of transmission losses in the supply system of electrified public transport...
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Evaluation of losses in a hydraulic motor based on the SWSB - 63 motor tests
PublikacjaIn this paper are compared two models of energy losses: that suggested by Prof. Paszota,Z. in monograph "Energy losses in the hydraulic displacement motors - definitions and relations serving the evaluation of the efficiency of hydrostatic drive" [18] and that ofProf. Balawender, A. in "Energy analysis and methodology of testing of low-speed hydraulic motors" [1]. By using the data obtained from the tests of SWSB-63 hydraulic motors...
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Investigation method and mathematical model of pressure losses in hydraulic rotary motor
PublikacjaTis paper presents a way of determining the coefcient k of the pressure losses Δp (fow drag) in internal ducts 8 Mp of SWSB-63 hydraulic motor. Te coefcient is determined at a fow rate equal to the theoretical capacity Q of the Pt pump feeding the motor , the losses are related to the nominal pressure p in the hydraulic system. Te investigations n followed a model of energy performance of hydraulic rotary motor, proposed by...
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Losses and power balance in hydraulic satellite motor supplied with oil and HFA-E emulsion
PublikacjaMineral oil and HFA-E emulsion are liquids which differ in viscosity, density and lubricant properties. Therefore, supplying hydraulic satellite motor with these liquids, differences between quantity of hydraulic, volumetric and mechanical losses are observed. These losses influence efficiency of conversion of hydraulic energy into mechanical energy and thereby power balance of motor. The research of satellite motor has been conducted...
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Mathematical model defining volumetric losses of hydraulic oil compression in a variable capacity displacement pump
PublikacjaThe objective of the work is to develop the capability of evaluating the volumetric losses of hydraulic oil compression in the working chambers of high pressure variable capacity displacement pump. Volumetric losses of oil compression must be determined as functions of the same parameters, which the volumetric losses due to leakage, resulting from the quality of design solution of the pump, are evaluated as dependent on and also...
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Magnetic and capacitive couplings influence on power losses in double circuit high voltage overhead transmission line
PublikacjaPurpose – The paper aims to discuss problems of power and energy losses in a double-circuit overhead transmission line. It was observed from energymeters’ readings, that in such a line, active power losses can be measured as “negative”. The “negative” active power losses appear when the active power injected to the circuit is lower than the active power received at the circuit end. The purpose of this paper is to explain this phenomenon. Theoretical...
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Quantitative study of free convective heat losses from thermodynamic partitions using Thermal Imaging
PublikacjaThe following paper presents a simple method of determining the presence, distribution and values of heat losses from external building walls as thermodynamic partitions using a Thermal Imaging Camera (TIC). According to Fourier's equation, the value of heat loss is proportional to the temperature gradient ∂t/∂y|y=0 in air in the y direction perpendicular to the heated surface. Unfortunately, air temperature cannot be measured...
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Activity coordination of capacitor banks and power transformer controllers in order to reduce power losses in the MV grid
PublikacjaOne of the main issues related to the optimization of the MV (middle voltage) network is to reduce losses of active and reactive power. Lower losses of active and reactive power give not only economic advantage, but also improvement of energy quality. The object of regulation that can be used for these purposes are transformer with On-Load Tap Changer and capacitor's banks. This paper presents results of analysis of the possibility...
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Analytical Estimation of Power Losses in a Dual Active Bridge Converter Controlled with a Single-Phase Shift Switching Scheme
PublikacjaMicro-grid solutions around the world rely on the operation of DC/DC power conver- sion systems. The most commonly used solution for these topologies is the use of a dual active bridge (DAB) converter. Increasing the efficiency and reliability of this system contributes to the improvement in the stability of the entire microgrid. This paper discussed an analytical method of energy efficiency and power loss estimation in a single...
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Michał Ryms dr hab. inż.
Osobydr hab. inż. Michał Ryms, fizyk, absolwent Politechniki Gdańskiej. Pracę doktorską obronił na Wydziale Chemicznym. Od 2011 roku pracuje w Katedrze Konwersji i Magazynowania Energii Politechniki Gdańskiej, obecnie na stanowisku profesora uczelni. Działalność naukowa obejmuje: zagadnienia związane z poprawą efektywności energetycznej oraz możliwości nowego zastosowania materiałów zmiennofazowych (PCM) głównie w budownictwie energooszczędnym...
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Wpływ właściwości czynników chłodniczych na straty egzergii w pompie ciepła (Influence of Refrigerants Properties for Exergy Losses in Heat Pump)
PublikacjaArtykuł poświęcony jest wpływowi występujących w pompie ciepła strat egzergii na jej efektywność energetyczną, a co za tym idzie koszty funkcjonowania instalacji. Autorzy prezentują tu metodologię obliczeniową, która może być zastosowana w procesach projektowania układów cieplno-przepływowych. Obliczenia zostały wykonane na podstawie typowego układu powietrznej pompy ciepła pracującej w klimacie środkowo-europejskim. Ponadto w...
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Energy Loss Coefficients ki in a Displacement Pump and Hydraulic Motor used in Hydrostatic Drives
PublikacjaThe article aims at defining and analysing the energy loss coefficients in design solutions of rotating displacement machines, with a piston machine as an example. The energy losses observed in these machines include mechanical loss, volumetric loss, and pressure loss. The scale and relations between these losses in different machines depend on machine design and manufacturing quality, and on operating parameters. The operating...
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HYDROSTATIC THRUST BEARING WITH REDUCED POWER LOSSES
PublikacjaIn many cases in rotating machinery, axial load is carried by tilting pad thrust bearings which have been developed since the beginning of 20th century. For high reliability and simplicity, most commonly the bearings are bath lubricated. In the times of sustainable development, however, minimization of friction losses becomes an important criterion for machinery assessment, and a strategic goal of their development. Performed calculations,...
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Overview of Approaches for Compensating Inherent Metamaterials Losses
PublikacjaMetamaterials are synthetic composite structures with extraordinary electromagnetic properties not readily accessible in ordinary materials. These media attracted massive attention due to their exotic characteristics. However, several issues have been encountered, such as the narrow bandwidth and inherent losses that restrict the spectrum and the variety of their applications. The losses have become the principal limiting factor...
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Post-harvest Losses of Agricultural Produce
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Testing the Weibull distribution in road traffic losses analysis
PublikacjaThe paper presents an attempt of applying the Weibull distribution for the purpose of analysing road traffic losses (fatalities). The question it asks is whether reliability engineering methods can be applied for the analyses. If this is the case, what should be the interpretation of the numbers and terms? It was assumed that the losses generated by a malfunctioning road transport system are fatalities. Risk exposure to these losses...
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Prospects of Decreasing Power Losses in a Hydrostatic Thrust Bearing
PublikacjaIn numerous machines, axial load is carried by tilting pad thrust bearings known since the beginning of 20th century. These bearings are commonly bath lubricated, which is simple, does not require any additional pumps, and, due to this, such systems are highly reliable. In a contemporary technology, however, minimization of friction losses became an important goal of machinery improvement. Calculations based on elementary rules...
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On power stream in motor or drive system
PublikacjaIn a motor or in a drive system the quantity of power increases in the direction opposite to the direction of power flow. Energy losses and energy efficiency of a motor or a drive system must be presented as functions of physical quantities independent of losses. Such quantities are speed and load. But the picture of power stream in a motor or in a drive system is presented in the literature in the form of traditional Sankey...
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Comparative study of a bottoming SRC and ORC for Joule–Brayton cycle cooling modular HTR exergy losses, fluid-flow machinery main dimensions, and partial loads
PublikacjaEnergy conversion efficiency increase in power plants with high-temperature gas-cooled reactors via implementation of the bottoming cycle was investigated under nominal and minimal thermal load of a high-temperature reactor (HTR). Heat transfer surface area and turbine outlet volumetric flow rate in bottoming cycles was also investigated. Water and two low-boiling point working fluids (ammonia and ethanol) were analyzed. Analyzed...
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The nonlinear effects of sound in a liquid with relaxation losses
PublikacjaThe nonlinear effects of sound in electrolyte with a chemical reaction are examined. The dynamic equations that govern non-wave modes in the field of intense sound are derived, and acoustic forces of vortex, entropy, and relaxation modes are determined in the cases of low-frequency sound and high-frequency sound. The difference in the nonlinear effects of sound in electrolyte and in a gas with excited vibrational degrees of molecules,...
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The Influence of Water and Mineral Oil on Pressure Losses in Hydraulic Motor
PublikacjaIn this paper, pressure losses in hydraulic motor supplied with water and mineral oil (two liquids that have significantly different viscosity and lubricating properties) are described and compared. The experimental tests were conducted using a hydraulic satellite motor that is dedicated to working with different liquids, including water. The methodology of measuring the pressure drop in internal channels of this motor is also...
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The influence of water and mineral oil on volumetric losses in a hydraulic motor
PublikacjaIn this paper volumetric losses in hydraulic motor supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and comparison. The experimental tests were conducted using an innovative hydraulic satellite motor, that is dedicated to work with different liquid, including water. The sources of leaks in this motor are characterized and described also. On this...
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Losses and raw material yield of wood saeing processes
PublikacjaW artykule opisano sposób wyznaczania bezwzględnych i względnych strat materiałowych, jak również wydajności materiałowej w procesie przecinania drewna.
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PRESSURE LOSSES AND POWER BALANCE IN THE UNLOADED SATELLITE PUMP
PublikacjaThis paper presents the results of laboratory research the pressure drop in the internal channels of unloaded satellite pump pumping tap water. Also shows the characteristics of the increase of pressure in the working chamber of the pump. It has been shown that after reaching cavitation, increase pump speed will increase in torque. This is the moment of inertia caused by the increase of the operating mechanism and the liquid contained...
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Pressure losses and power balance in the unloaded satellite pump
PublikacjaThis paper presents the results of laboratory research the pressure drop in the internal channels of unloaded satellite pump pumping tap water. Also shows the characteristics of the increase of pressure in the working chamber of the pump. It has been shown that after reaching cavitation, increase pump speed will increase in torque. This is the moment of inertia caused by the increase of the operating mechanism and the liquid contained...
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Influence of the thermal modernization of window on transmission heat losses
PublikacjaThe article presents the results of calculations of the heat transfer coefficient for the state before and after renovation for the historic windows. The aim of the analysis was to obtain the values of thermal insulation parameters demanded by the regulations, while not losing the historical value of the window. The described example of the renovation of the existing window consisted in installing an additional window panel from...
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Power balance in hydraulic satellite motors supplied with oil and HFA-E emulsion
PublikacjaMineral oil and HFA-E emulsion are liquids which differ in viscosity, density and lubricant properties. Therefore, supplying hydraulic satellite motors with these liquids, differences between quantity of hydraulic, volumetric and mechanical losses are observed. These losses influence efficiency of conversion of hydraulic energy into mechanical energy and thereby power balance of motors.
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Diagnosing marine turbine engines through energy characteristics of their flow section
PublikacjaThe aim of the performed research was to develop of diagnostic method of the flow section of a marine turbine combustion engine based on the level of delamination of its energy characteristics. The here adopted diagnostic model provides for a formulation of the evaluation of the technical conditions based on the measurements of the parameters of the thermodynamic medium in the characteristic control cross-sections of the engine...
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HEAD LOSSES IN SMALL HYDROPOWER PLANT TRASH RACKS (SHP)
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Chapter 19: Physical and mathematical models of losses in hydraulic motors
PublikacjaOpisano bilans energii w silniku hydraulicznym z uwzględnieniem strat mechanicznych, objętościowych i ciśnieniowych opisanych modelami fizycznymi i matematycznymi.
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Impact of WDM Network Topology Characteristics on the Extent of Failure Losses
PublikacjaW artykule dokonano oceny wpływu charakterystyk topologicznych sieci na rozmiar strat po awarii węzła/łącza będącej następstwem ataku. W tym celu wprowadzono współczynnik ATRF. Wyniki badań pokazały, że wykorzystanie standardowej metryki odległości do wyznaczania tras podstawowych prowadzi do istotnego zwiększenia liczby połączeń uszkodzonych w wyniku ataku w porównaniu ze skutkami awarii losowej.
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Effect of the working liquid compressibility on the picture of volumetric and mechanical losses in a high pressure displacement pump used in a hydrostatic drive Part II Mechanical losses in a pump
PublikacjaŚciśliwość cieczy roboczej może znacząco zmienić wartości i proporcje współczynników strat objętościowych i mechanicznych w pompie wyporowej zastosowanej w układzie napędu hydrostatycznego. Wpływ ten jest szczególnie widoczny w trakcie pracy pod wysokim ciśnieniem a także wówczas, gdy występuje zapowietrzenie cieczy roboczej. W części II przedstawiono model matematyczny momentu strat mechanicznych w pompie oraz jego laboratoryjną...
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Transmission Losses Spatial Analysis of the Supply System of Electrified Urban Transport Network
PublikacjaThe paper presents mathematical model TOPSIS which was applied for MCDA benchmark of trolleybus supply system. Moreover, paper presents the novel method of transmission losses analysis in electrified urban transport system. Research work was based on measurements realized in Gdynia trolleybus network.
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The influence of water and mineral oil on volumetric losses in the displacement pump for offshore and marine applications
PublikacjaIn this paper volumetric losses in a positive displacement pump supplied with water and mineral oil are described and compared. The experimental tests were conducted using a prototype of a satellite pump (with a non-circular tooth working mechanism). In this paper the sources of volumetric losses in this pump are characterised. On this basis, a mathematical model of these losses has been presented. The results of the calculation...
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The impact of the overhead line's power supply system spatial differentiation on the energy consumption of trolleybus transport: planning and economic aspects
PublikacjaNowadays the issue of electric energy saving in public transport is becoming a key area of interest, which is connected both with a growth in environmental awareness of the society and an increase in the prices of fuel and electricity. It can be achieved by reducing of the transmission losses in supply system or by the improving of the usage of the regenerative breaking. The spatial differentiation of the energy supply system of...