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Search results for: HEAT PUMPS
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HIGH TEMPERATURE HEAT PUMPS – PERSPECTIVE HEATING SYSTEMS?
PublicationIn the paper presented are authors own concepts of high temperature compressor heat pumps for the utilisation of medium and low temperature sources of heat. Working fluids for use in high temperature heat pumps are discussed, as well as the criteria for their selection. Analyses are presented for the production of in the upper steam source at 130 °C. One-stage systems and cascade systems were analyzed. An analysis of the coefficient...
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High-temperature heat pumps – potential technology for heat recovery and production of process heat
PublicationIn the paper, the high temperature vapour compressor based heat pump with a selection of working fluids, both perspective and ecological ones, is considered. Such system is not yet commercially available on the market and in author’s opinion it has significant potential for various applications. In the presented analysis it was assumed that the heat source has a temperature of 50oC and the temperature lift is 60, 80 and 100K respectively....
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High-temperature heat pumps – new devices for heat recovery and production of technological steam
PublicationIn the paper, the original high temperature compressor based heat pump with a dry working fluid, i.e. the one in which the slope of saturated vapour line is positive, was presented. The objective of the paper is to investigate the possibility of preparation of technological steam with tempperature 120 C from the waste heat resource at temperature of 50 C. Single comppression cycles as well as cascade systems have been considered...
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Ewa Klugmann-Radziemska prof. dr hab.
PeopleEwa Klugmann-Radziemska graduated from the University of Gdansk with a degree in physics, and since 1996 has been associated with the Gdansk University of Technology, when she began PhD studies. Currently, he is a professor at the Faculty of Chemistry at the Gdansk University of Technology, since 2006 head of the Department of Chemical Apparatus and Machinery. In the years 2008–2016 she was the Vice-Dean for cooperation and development,...
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Performance of the very high-temperature heat pump with low GWP working fluids
PublicationTraditional heat pumps are a very attractive pro-ecological solutions for a number of applications, including providing of heating or heat recovery from industrial processes. The application range of heat pumps could be greatly enlarged when the operating temperature would be increased to 130-150°C and/or the temperature lift can be increased to 50-100 K. In the paper, the very high temperature vapour-compressor based single stage...
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Metal-organic frameworks (MOF) based heat transfer: A comprehensive review
PublicationHigher than a standard level, the humidity provides a suitable environment for the pathogenic microorganisms to grow and increases energy consumption for cooling, increasing greenhouse gas emissions. Desiccant air-conditioning (DAC) is an effective method to reduce humidity and energy simultaneously. Conventional desiccants are not suitable for use as a desiccant in building air conditioners, mainly because of high regeneration...
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Pressure drop and heat transfer during boiling and condensation at subcritical region
PublicationMost of the data presented in the literature relate to saturation temperatures in the range - 20°C to 40°C due to the application in refrigeration technology. There is necessity to extend databases to higher values of saturation temperature due to new applications such as Organic Rankine Cycle and high temperature heat pumps. Only few papers contain data for high reduced pressure for low boiling point liquids. This paper focus...
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Wpływ właściwości czynników chłodniczych na straty egzergii w pompie ciepła (Influence of Refrigerants Properties for Exergy Losses in Heat Pump)
PublicationArtykuł 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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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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Charakterystyka eksploatacyjna pomp ciepła zainstalowanych w oczyszczalni ścieków
PublicationW artykule przedstawiono charakterystykę eksploatacyjną sprężarkowych pomp ciepła zainstalowanych w oczyszczalni komunalnej i wykorzystujących ścieki oczyszczone jako dolne źródło ciepła. Zastosowanie ścieków oczyszczonych jest uzasadnione ich dostępnością oraz stosunkowo wysoką temperaturą (10-25°C). Prawidłowa eksploatacja układu wymaga zastosowania pośredniego obiegu parowacza oraz regularnych zabiegów czyszczenia wymiennika...
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Funkcjonowanie zespołów napędu hydraulicznego maszyn w niskich temperaturach otoczenia
PublicationW pracy przedstawiono cztery warianty klasyfikacji rozruchów oziębionego napędu hydraulicznego. Pierwsza sytuacja dotyczy zagadnienia, w którym wszystkie zespoły układu napędowego wraz z olejem mają taką samą niską temperaturę podczas rozruchu. Pozostałe warianty odnoszą się do rozruchu w warunkach szoku termicznego wywołanych zasilaniem ciepłym czynnikiem roboczym oziębionych zespołów hydraulicznych. Rozruch zespołów...
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Porównanie działania transformatora symetryzującego (zygzak) z aktywnym energoelektronicznym symetryzatorem prądów fazowych linii niskiego napięcia
PublicationNa potrzeby planowania sieci niskiego napięcia operatorzy systemów dystrybucyjnych (OSD) zakładają symetryczne warunki obciążenia linii. Z roku na rok, rośnie liczba rozproszonych systemów fotowoltaicznych (PV) zainstalowanych w sieciach niskiego napięcia, których większość to małe jednofazowe systemy dachowe. Dodatkowo, do niesymetrii obciążenia przyczyniają się instalowane masowo pompy ciepła i ładowane jednofazowo samochody...
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Volumetric and torque efficiency of pumps during start-up in low ambient temperatures
PublicationThe volumetric, torque and total efficiency of hydraulic pumps change during start-up in low ambient temperatures, as well as in thermal shock conditions, un-til they reach the set conditions. The time to reach steady-state conditions de-pends on many parameters: ambient temperature, flow rate, fluid temperature, design of hydraulic units. The author carried out tests of hydraulic pumps in the Hydraulics Laboratory of the Faculty...
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New satellite pumps
PublicationStosowanie Maszyn company from Katowice was initiator and originator of newest original high pressure satellite pumps series of types PSM. Construction solution, research and development of these pumps have been conducted by Team of Hydraulics and Pneumatics of Gdansk University of Technology in cooperation with this company within the confines of research project nr R0300103 (source of funds: Ministry of Science and Higher Education)....
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RESEARCH OF HYDRAULIC PISTON PUMPS’ START-UP IN LOW AMBIENT TEMPERATURES
PublicationStarting hydraulic pumps in low ambient temperatures may cause: decreased hydraulic-mechanical efficiency, larger vibration of hydraulic installation, faster wear and more frequent damage to the elements of pumps, change of material properties of elements, increase of pressure drop. As a result of increase of resistance of cold oil flow in the suction pipe, large underpressure may be experienced, causing incomplete filling of pump...
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Sustainable energy consumption – Empirical evidence of a household in Poland
PublicationThere is an expected increase in the demand for electricity from households in European countries. The outcome of the growing proportion of renewable energy sources in the energy supply mix should result in improved customer awareness regarding their electricity usage. Additionally, they must assume a more proactive role in overseeing their electricity usage. Innovation and pollution management have become crucial catalysts for...
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Influence of Bingham fluid viscosity on energy performances of a vortex chamber pump
PublicationOne of the problems in the development of coal-water technologies is the use of reliable and long-lasting pumps. To date, classic pumps, due to the use of mechanical moving parts and seals, are subject to rapid abrasive wear. The solution to this problem can lie in the creation of new vortex chamber pumps developed by the authors. They are highly reliable, simple in design and have no moving parts. The object of this paper consists...
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Multi-objective optimization of water quality, pumps operation, and storage sizing of water distribution systems
PublicationA multi-objective methodology utilizing the Strength Pareto Evolutionary Algorithm (SPEA2) linked to EPANET for trading-off pumping costs, water quality, and tanks sizing of water distribution systems is developed and demonstrated. The model integrates variable speed pumps for modeling the pumps operation, two water quality objectives (one based on chlorine disinfectant concentrations and one on water age), and tanks sizing cost...
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R&D of satellite pumps and motors with small geometrical displacement supplied with oil and non-flammable liquids
PublicationThe newest construction of satellite motors and self-suction satellite pumps with small geometrical displacement have been described in this article. The characteristics of volumetric and total efficiency of one satellite motor, selected from the series, supplied with oil have been presented. These characteristics have been compared with the orbital motors' characteristics. The remaining specifications of these motors were also...
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Diagnostics of commutation unit in satellite pumps and motors
PublicationThe article describes a part of the research on the development of satellite pumps and motors, conducted on Gdansk University of Technology as a part of grant "New elaborate of hydraulic satellite machines for drives with vegetable liquids and non-flammable liquids" (LIDER/35/102/L-2/10/NCBiR/2011) funded by the National Centre for Research and Development in Poland. The presented area includes the diagnostics of commutation units...
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Diagnostics of commutation unit in satellite pumps and motors
PublicationThe article describes a part of the research on the development of satellite pumps and motors, conducted on Gdansk University of Technology as a part of grant "New elaborate of hydraulic satellite machines for drives with vegetable liquids and non-flammable liquids" (LIDER/35/102/L-2/10/NCBiR/2011) funded by the National Centre for Research and Development in Poland. The presented area includes the diagnostics of commutation units...
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Selected aspects of determining the reliability of the pump subsystems with redundancy, used in main engine auxiliary systems
PublicationThe rules of classification societies require the use of redundancy in the systems essential for the safety of the ship. Duplication of pumps in the main engine auxiliary systems like cooling water system, lubricating oil system, fuel oil system is a good example here. Therefore, in the author's opinion, some attention should be paid to this issue. Two important questions arise here. Does duplication of pumps in marine systems...
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Influence of Gaps’ Geometry Change on Leakage Flow in Axial Piston Pumps
PublicationAxial piston pumps are the core elements of most medium and high-pressure hydraulic systems. High volumetric efficiency and high working pressures are the main advantages of this type of pumps. Therefore it is necessary to accurately calculate the leakage flow through the gaps to design efficient high-pressure pump. The main difficulty of such calculations is the fact, that the gaps change their geometry during pumping process....
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Compensation of pressure peaks in pwk-type hydraulic pumps
Publicationhydraulic axial pumps equipped with cam-driven commutation unit (pwk pumps) proved their high efficiency up to 55 mpa and ability to work self-sucking, even at high speed. displacement of pwk pump may easily be changed by moving its control cam. full discharge from hydrostatic forces makes such control possible by direct action of a low-energy actuator like proportional electromagnet or stepping motor. that eliminates heavy and...
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Turbomachinery - Background
PublicationThe "Turbomachinery - Background" is the first part of a series of monographs devoted to different aspects of rotating machines. The book presents the main fundamentals which are necessary for the different problems of steam, gas, wind and water turbines as well as pumps, compressors and propellers which will discussed in detail in the subsequent parts of the series.
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Influence of the low ambient temperature on the start-up process of hydraulic pumps
PublicationStarting hydraulic pumps in low ambient temperatures may cause: decreased hydraulic-mechanical efficiency, larger vibration of hydraulic installation, faster wear and more frequent damage to the elements of pumps, change of material properties of elements, increase of pressure drop. As a result of pressure drop in the suction pipe, large underpressure may be experienced, causing incomplete filling of pump working chambers with...
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Laboratory test rig for examining aggregate mining from seabed using the AIRLIFT method
PublicationThe use of the Airlift method for transporting the mined aggregate from the seabed to the deck of the mining ship is an alternative for presently used solutions, such as suction pumps or scoop transport for instance. Building the laboratory test rig was preceded by tests in natural conditions. The rig was designed in such a way as to model these conditions as close as possible, and to have potential for further development
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Selection of drive engines for dredge pumps
PublicationThis paper presents the principles of selecting drive engines for dredge pumps, formulated by this author. In order to formulate them influence of drive engines on dredge pump characteristics and dredger effectiveness, have been analyzed. Also, an analysis of results of the author's operational investigations concerning energy consumption and parameters of excavated soil transport on board dredgers has been performed.
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Metodyka badań rozwojowych nowego typu silników i pomp satelitowych
PublicationResearch and development of new type satellite motors and satellite pumps SM with small geometrical displacement, from 5 to 73 cm3/rev, has been conducted in cooperation with Stosowanie Maszyn company from Katowice (manufacturer of motors and pump SM). The improvement of construction of those machines, especially construction of axial compensation and construction of fluid distribution channels have been the main problem of research...
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Sliding bearings with sintered bronze bush lubricated by contaminated water with solid particles – Theoretical and experimental studies
PublicationSliding journal bearings lubricated with water coming directly from the environment are a solution used in shipbuilding, pumps and hydropower. However, the working fluid or surrounding water cannot always be filtered because of design limitations, which often causes the problem of premature wear of these sensitive bearings. The research conducted made it possible to assess the wear of sliding bearings lubricated with water containing...
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Displacement control in PWK-type pumps
PublicationThe most important, strategic goal however is creation of the variable displacement version of the new pump PWK. Thanks to full discharge of it's commutation mechanism from hydrostatic forces the variable pump can be directly controlled by low-energy actuator like proportional electromagnet or stepping motor. It means that costly and complicated hydraulic servomechanism (applied in all present variable displacement pumps) is no...
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Experience of hybrid constructed wetlands operation in Gdansk region
PublicationThe investigation were carried out at five local hybrid constructed wetlands (HCWs), which secured biological treatment of domestic wastewater generated from 15 to 600 pe. Based on over two years monitoring it was indicated that HCWs ensured very effective removal of organic matter from 74.9 to 95.5 COD % in wild range of loadings (1.5 - 17.0g COD/ m3day). Efficiency of total nitrogen removal varied significantly from 23.4 two...
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WATER LUBRICATED MAIN SHAFT BEARINGS - MODERN SOLUTION FOR HYDROPOWER INDUSTRY - Experimental and theoretical studies
PublicationWater-lubricated bearings are finding increasingly wide use in various branches of industry. As such, they may also be encountered in hydro power industry. They are also increasingly frequently employed in bearing systems of marine shaft propulsions and water pumps [1]. This rising popularity is due to a number of reasons [2]. First of all, their simple construction has direct impact on the level of pricing which is usually quite...
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Prospects of Decreasing Power Losses in a Hydrostatic Thrust Bearing
PublicationIn 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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Protection System Design of Induction Motor for Industries
PublicationThe fundamental and durable structures of induction motor, as well as their low manufacturing cost, make them popular components in a wide range of current applications. Providing a safety net for employees is a must-have for businesses. This project’s motivation for improvement is to provide industrial motors, lift motors, pumps, and so on with safety. An induction motor’s primary goal is to protect it from problems, such as...
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Protection System Design of Induction Motor for Industries
PublicationThe fundamental and durable structures of induction motor, as well as their low manufacturing cost, make them popular components in a wide range of current applications. Providing a safety net for employees is a must-have for businesses. This project’s motivation for improvement is to provide industrial motors, lift motors, pumps, and so on with safety. An induction motor’s primary goal is to protect it from problems, such as...
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Chemosensitization of multidrug resistant Candida albicans by the oxathiolone fused chalcone derivatives
PublicationThree structurally related oxathiolone fused chalcone derivatives appeared effective chemosensitizers, able to restore in part sensitivity to fluconazole of multidrug-resistant C.albicans strains. Compound 21 effectively chemosensitized cells resistant due to the overexpression of the MDR1 gene, compound 6 reduced resistance of cells overexpressing the ABC-type drug transporters CDR1/CDR2 and derivative 18 partially reversed fluconazole...
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STUDY ON THE EFFECTIVENESS OF THE TURBINE CONDENSER AIR EXTRACTION SYSTEM USING HYDRO EJECTORS
PublicationThe aim of the paper is to investigate the effectiveness of the 18K380 steam turbine condenser air extraction system using hydro ejectors. Motivation for the analysis is a need of improvement of the energy conversion ratio of the power plant. To achieve this goal it is necessary to establish efficiency of each subsystem of the energy cycle. The air extraction system is not a highly power consuming system but it has great impact...
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Marine propeller shaft bearings under low-speed conditions: water vs. oil lubrication
PublicationThe bearings used in shipbuilding, hydropower, and water pumps have undergone a metamorphosis in recent decades. Because of environmental regulations, lubrication with grease or mineral oil is prohibited. Thus, the standard solutions include water-lubricated bearings with polymer bushings or sealed systems lubricated with oil. When properly designed, assembled, and operated, bearings can operate reliably for years. However, specific...
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Multiobjective Water Distribution Systems Control of Pumping Cost, Water Quality, and Storage-Reliability Constraints
PublicationThis work describes a multiobjective 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 multiobjective SPEA2 algorithm with EPANET, and is applied on two example applications of increasing complexity, under extended period simulation conditions and variable energy...
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APPLICATION OF THE THEORY OF SEMI-MARKOV PROCESSES TO DETERMINE A LIMITING DISTRIBUTION OF THE PROCESS OF CHANGES OF ABILITY AND INABILITY STATES OF FUEL SUPPLY SYSTEMS IN HEAVY FUEL DIESEL ENGINES
PublicationThe paper presents applicability of the theory of semi-Markov processes to determine a limiting distribution of the process of changes of technical states of fuel systems for marine engines running on heavy fuel oils. The proposed study of this process includes the components of such fuel systems like: 1 - injectors, 2 - high pressure hoses, 3 - injection pumps, 4 - low pressure hoses, 5 – fine filters, 6 - coarse filters, 7 – fuel-feed...
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Multi-Objective Water Distribution Systems Control of Pumping Cost, Water Quality, and Storage-Reliability Constraints
PublicationThis 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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EXPERIMENTAL RESEARCH ON INFLUENCE OF THE FUEL NOZZLE GEOMETRY ON THE FUEL CONSUMPTION OF THE MARINE 4-STROKE DIESEL ENGINE
PublicationThe article presents experimental research that has been carried out on a marine, 4-stroke, 3-cylinder, turbocharged engine. During testing, the engine operated at a constant rotational speed of 750 rpm and a load from 0 kW to 280 kW. The engine was fuelled by diesel oil of known specification and loaded by electric generator with water resistance. The fuel consumption was measured during the engine operation with fuel nozzles...
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Greenhouse control system design
PublicationCoraz większa populacja i zmniejszające się tereny uprawne wymusza efektywniejsze metody uprawy roślin. Zaradzić temu mogą układu hydroponiczne, które dzięki rozwojowi techniki są w stanie osiągać znacznie większe oraz bardziej jednorodne plony. Jest to możliwe dzięki zaawansowanym systemom opartym na dokładnych urządzeniach pomiarowych, sterowaniu w zamkniętej pętli oraz mikrokontrolerom umożliwiającym...
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‘Acridines’ as New Horizons in Antifungal Treatment
PublicationFrequent fungal infections in immunocompromised patients and mortality due to invasive mycosis are important clinical problems. Opportunistic pathogenic Candida species remain one of the leading causes of systemic mycosis worldwide. The repertoire of antifungal chemotherapeutic agents is very limited. Although new antifungal drugs such as lanosterol 14α-demethylase and β-glucan synthase inhibitors have been introduced into clinical...
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Experimental Research of an Axial Piston Pump with Displaced Swash Plate Axis of Rotation
PublicationThe article describes the influence of displacement of the swash plate rotation axis on the efficiency of axial piston pumps. The dead space volume was defined as the volume of the working chamber in the extreme position of the piston at the end of the pumping phase and its variability was determined as a function of the position of the axis of rotation of the swash plate and the swing angle of swash plate. The influence of swash...
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Simulation of fluid structure interaction in a novel design of high pressure axial piston hydraulic pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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Simulation of fluid structure interaction in a novel design of high pressure axial piston pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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Xanthone synthetic derivatives with high anticandidal activity and positive mycostatic selectivity index values
PublicationWith the current massive increases in drug-resistant microbial infection as well as the significant role of fungal infections in the death toll of COVID-19, discovering new antifungals is extremely important. Natural and synthetic xanthones are promising derivatives, although only few reports have demonstrated their antifungal mechanism of action in detail. Newly synthetized by us xanthone derivative 44 exhibited strong antifungal...
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Effect of presence of lifting pocket on the THD performance of a large tilting-pad thrust bearing
PublicationHydrostatic assistance is a commonly used method to improve limited load carrying ability of tiltingpad thrust bearings during transient states of operation of vertical shaft hydro-generators. Despite of special hydraulic equipment (as pumps, valves, etc.), it also requires manufacturing of special recesses/pockets at pad sliding surfaces, into which oil is injected under high pressure. It allows to lift the rotor before start-up...