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Wyniki wyszukiwania dla: MECHANIZM OF FREEZING OF WATER
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Balance errors in numerical solutions of shallow water equations
PublikacjaThe analysis of the conservative properties of the shallow water equations is presented in the paper. The work focuses on the consistency of numerical solution of these equations with the conservation laws of mass and momentum. The investigations involve two different conservative forms which are solved by an implicit box scheme. The theoretical analysis supported by numerical experiments is carried out for rectangular channel...
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Elastic scattering of electrons by water: An ab initio study
PublikacjaIn this work we devise a theoretical and computational method to compute the elastic scattering of electrons from a non-spherical potential, such as in the case of molecules and molecular aggregates. Its main feature is represented by the ability of calculating accurate wave functions for continuum states of polycentric systems via the solution of the Lippmann-Schwinger equation, including both the correlation effects and multi-scattering...
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Solubility of carbon dioxide in water: Some useful results for hydrate nucleation
PublikacjaIn this paper, the solubility of carbon dioxide (CO2) in water along the isobar of 400 bar is determined by computer simulations using the well-known TIP4P/Ice force field for water and the TraPPE model for CO2. In particular, the solubility of CO2 in water when in contact with the CO2 liquid phase and the solubility of CO2 in water when in contact with the hydrate have been determined. The solubility of CO2 in a liquid–liquid...
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Hyperbranched polyethylenimine functionalized silica/polysulfone nanocomposite membranes for water purification
PublikacjaHyperbranched polyethyleneimine functionalized silica (PEI-SiO2) nanoparticles with considerable hydrophilicity were synthesized and incorporated into a polysulfone (PSF)/dimethylacetamide (DMA)/polyvinylpyrrolidone (PVP) membrane casting solution in five different ratios to fabricate PEI-SiO2/PSF nanocomposite membranes using nonsolvent-induced phase separation. The hydrophilic PEI-SiO2 nanoparticles were characterized by TEM,...
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Analyzing the Impact of Simulated Multispectral Images on Water Classification Accuracy by Means of Spectral Characteristics
PublikacjaRemote sensing is widely applied in examining the parameters of the state and quality of water. Spectral characteristics of water are strictly connected with the dispersion of electromagnetic radiation by suspended matter and the absorp-tion of radiation by water and chlorophyll a and b.Multispectral sensor ALI has bands within the ranges of electromagnetic radia-tion: blue and infrared, absent in sensors such as Landsat, SPOT,...
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Modeling of Cardiac Component of Subarachnoid Space Changes in Apnoea Resulting as a Function of Blood Pressure and Blood Flow Parameters - Two Mechanizm of Regulation
PublikacjaExperiments were performed in a group of 19 healthy, non-smoking volunteers. The experiment consisted of three apnoeas, sequentially: 30 s apnoea, 60 s apnoea and maximal, that could be done, apnoea. The breath-hold was separated for 5 minutes rest. The following parameters were measured and obtained for further analysis: blood parameters, artery diameter of the internal carotid artery, end-tidal CO2 in expired air, the cardiac...
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Bismuth-based nanomaterials-assisted photocatalytic water splitting for sustainable hydrogen production
PublikacjaThe rapidly increase in the world's population has resulted in a corresponding increase in the energy demand. This demand is largely being met by fossil fuels for power generation, industrial fuel and transportation. However, due to the limited availability of fossil fuels and their negative effects on the environment. The use of fossil fuels results in by-products such as carbon, nitrogen and sulfur oxides which have negative...
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Bismuth-based nanomaterials-assisted photocatalytic water splitting for sustainable hydrogen production
PublikacjaThe rapidly increase in the world's population has resulted in a corresponding increase in the energy demand. This demand is largely being met by fossil fuels for power generation, industrial fuel and transportation. However, due to the limited availability of fossil fuels and their negative effects on the environment. The use of fossil fuels results in by-products such as carbon, nitrogen and sulfur oxides which have negative...
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Shallow-Water Acoustic Communications in Strong Multipath Propagation Conditions
PublikacjaA phenomenon that has a strong impact on signal transmission conditions in Underwater Acoustic Communication (UAC) systems is multipath propagation. As a result of multipath propagation, the transmitted signal undergoes time dispersion which results in inter-symbol interference observed on the receiving side. Time dispersion is large, especially in horizontal channels in shallow waters which significantly limits the transmission...
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Shipping Low Frequency Noise and Its Propagation in Shallow Water
PublikacjaOne of the most significant factor influencing acoustical climate of the sea is underwater noise generated by moving ships. If the considered sea area has features of the shallow water, namely the wave frequency fulfils relation f < 10c/h, where c denotes phase speed of sound, and h is depths of the sea, then in certain distance from the wave source specific image of sound pressure distribution in the mean of wave modes appears....
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Determination of metals in water samples by atomic absorption spectrometry and flame emission spectrometry
PublikacjaMetal species in environmental waters are relevant to characterize the metal toxicity, the mobility between different environmental compartments, and for remediation purposes in case of contamination. The concentration of many trace metals in natural water samples are generally at µg/l level. The paper describes determination of metals in water samples based on flame atomic emission and flame atomic absorption spectrometry.
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The importance of the shape of the protein–water interface of a kinesin motor domain for dynamics of the surface atoms of the protein
PublikacjaA single kinesin motor domain immersed in water has been investigated using molecular dynamics. It has been found that local properties of water in the solvation shell change along with the nature of the neighboring protein surface. However, a detailed analysis leads to the conclusion that the geometrical features of hydrogen bonds and overall structure of kinesin hydration water are not very different from bulk water. The local...
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The importance of the shape of the protein-water interface of a kinesin motor domain for dynamics of the surface atoms of the protein
PublikacjaSingle kinesin motor domain immersed in water has been investigated using molecular dynamics. It has been found that local properties of water in solvation shell change along with the nature of neighboring protein surface. However, a detailed analysis leads to the conclusion that the geometrical features of hydrogen bonds and overall structure of kinesin hydration water is not very different from bulk water. The local values of...
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Study of the formation of calcareous deposits on cathodically protected steel in Baltic sea water
PublikacjaPurpose – The purpose of this paper is to investigate whether the sedimentation of calcareous deposits occurs on cathodically protected steel in Baltic sea water. Design/methodology/approach – Steel electrodes were cathodically polarized in natural Baltic sea water at potential þ0.150 V vs Zn electrode in potentiostatic mode. During exposure chronoamperometric measurements were carried out. After the exposure, the electrode’s surface...
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Water-mediated influence of a crowded environment on internal vibrations of a protein molecule
PublikacjaThe influence of crowding on the protein inner dynamics is examined by putting a single protein molecule close to one or two neighboring protein molecules. The presence of additional molecules influences the amplitudes of protein fluctuations. Also, a weak dynamical coupling of collective velocities of surface atoms of proteins separated by a layer of water is detected. The possible mechanisms of these phenomena are described....
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Monitoring of Chlorine Concentration in Drinking Water Distribution Systems Using an Interval Estimator
PublikacjaThis paper describes the design of an interval observer for the estimation of unmeasured quality state variables in drinking water distribution systems. The estimator utilizes a set bounded model of uncertainty to produce robust interval bounds on the estimated state variables of the water quality. The bounds are generated by solving two differential equations. Hence the numerical efficiency is sufficient for on-line monitoring...
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Data and knowledge supporting decision-making for the urban Food-Water-Energy nexus
PublikacjaCities are hubs of innovation and wealth creation, and magnets for an increasing urban population. Cities also face unprecedented challenges in terms of food, water and energy scarcity, and governance and management. Urban environmental issues are no longer problems for experts to address but have become issues of public debate, in which knowledge from multiple sectors is needed to support inclusive governance approaches. Consequently,...
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Shallow Water Experiment of OFDM Underwater Acoustic Communications
PublikacjaThe large variability of communication properties of underwater acoustic channels, and especially the strongly varying instantaneous conditions in shallow waters, is a challenge for the designers of underwater acoustic communication (UAC) systems. The use of phase modulated signals does not allow reliable data transmission through such a tough communication channel. However, orthogonal frequency-division multiplexing (OFDM), being...
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Non-ergodic fragmentation upon collision-induced activation of cysteine–water cluster cations
PublikacjaCysteine–water cluster cations Cys(H2O)3,6 + and Cys(H2O)3,6H+ are assembled in He droplets and probed by tandem mass spectrometry with collision-induced activation. Benchmark experimental data for this biologically important system are complemented with theory to elucidate the details of the collisioninduced activation process. Experimental energy thresholds for successive release of water are compared to water dissociation energies...
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The significance of the properties of water for the working cycle of the kinesin molecular motor
PublikacjaExplicit solvent molecular dynamics simulations were performed in this study to investigate and discuss several aspects of the influence of the properties of water on the working cycle of a molecular motor from the kinesin superfamily. The main objects of attention were: the binding of the neck linker and the association of the kinesin and the tubulin. The docking of the neck linker is considered a crucial event during the working...
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Degradation of 1,4-dioxane by sono-activated persulfates for water and wastewater treatment applications
PublikacjaThis paper presents a hybrid advanced oxidation process (AOP) based on sonocavitational activation of persulfate (PS) for degradation of 1,4-dioxane during wastewater treatment. Application of sono-cavitation effectively convert PS to radical species demonstrating synergistic effect by increasing the reaction rate and reducing the required energy for activation. It is economically feasible and deployed alternative to the direct...
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Long-term hindcast simulation of water temperature and salinity in the Baltic Sea
Dane BadawczeThe dataset contains the results of numerical modelling of water temperature and salinity over a period of 50 years (1958-2007) in the Baltic Sea. A long-term hindcast simulation was performed using a three-dimensional hydrodynamic model PM3D (Kowalewski and Kowalewska-Kalkowska, 2017), a new version of the M3D model (Kowalewski, 1997). The hydrodynamic...
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UAV Survey Images - 3D Model - GUT Water Tower MP1
Dane BadawczeDataset description: Raw images from photogrammetric survey. Object: Water Tower at Gdansk University Of Technology CampusLocation: Gdansk, Pomerania, PolandDrone type: DJI Mavic Pro 1Flight plan: CircleTarget Product: 3D ModelDate: 13.05.2019Direct georeferencing: yesMetadata data: yes/GPSGCP: NoGCP Quality: N/ACamera Name: DJI FC220Model type: PerspectiveImage...
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UAV Survey Images - 3D Model - GUT Water Tower MP2
Dane BadawczeDataset description: Raw images from photogrammetric survey. Object: Water Tower at Gdansk University Of Technology CampusLocation: Gdansk, Pomerania, PolandDrone type: DJI Mavic Pro 2Flight plan: CircleTarget Product: 3D ModelDate: 08.11.2019Direct georeferencing: yesMetadata data: yes/GPSGCP: NoGCP Quality: N/ACamera Name: Hasselblad L1D-20cModel...
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Water Reservoirs as an Element of Shaping Water Resources of Post-Mining Areas
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Physical modelling of water flow in 'Wild River' type water slide
PublikacjaPrzedstawiono wyniki fizycznego modelowania przepływu w zjeżdżalni wodnej typu Dzika Rzeka. Badania dotyczyły obiektu należącego do parku wodnego "Świat Wodny Nemo" w Sopocie. Eksperymenty przeprowadzono w Laboratorium Hydrauliki i Inżynierii Środowiska Politechniki Gdańskiej. Zaobserwowany w systemie kanałów i zbiorników przepływ wody można ocenić jako szybkozmienny. Wskutek zmian spadku dna kanałów oraz łuków trasy zjazdu obserwowano...
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Performance of the flat plate solar collector operated with water-Al2O3 nanofluid
PublikacjaThe paper discusses the effect of application of water-Al2O3 nanofluid, as a working fluid, on the efficiency of a flat plate solar collector. The mass concentration of nanoparticles was 0.1%, 0.2% and 0.4%. The tests were conducted for two values of radiation of about 1050 W/m2 and 400 W/m2, and volume flow rates of 60 l/h, 120 l/h and 170 l/h. The efficiency was calculated according to recommendations of the Polish Standard....
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Hydro Lubricants: Water-based lubricants for hydropower applications
PublikacjaSeveral different base oil types exist in the market including mineral and synthetic oils (e.g. polyalphaolefins, ester, polyglycol, etc.) and are currently widely in use. Although synthetic oils have drawn great attention over the past few decades in terms of their tribological benefits, mineral oils are still widely used in hydropower applications due primarily to their low cost and easy miscibility with other oils. However,...
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Role of the Solvation Water in Remote Interactions of Hyperactive Antifreeze Proteins with the Surface of Ice
PublikacjaMost protein molecules do not adsorb onto ice, one of the exceptions being so-called antifreeze proteins. In this paper, we describe that there is a force pushing an antifreeze protein molecule away from the ice surface when it is not oriented with its ice-binding plane toward the ice and that this pushing force may be also present even when the protein is oriented with its ice-binding plane toward the ice. This force is absent...
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Microorganisms’ communities from ballast water transferred into the Odra River estuary
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Substance Flow Analysis of Mercury Affecting Water Quality in the European Union
PublikacjaW pracy zastosowano metodę SFA (Substance Flow Analysis) do oceny źródeł transportu i składowania rtęci w wodzie na terenie UE. W wyniku analizy stopnia zanieczyszczenia środowiska w przeszłości jak i scenariuszy zmian tego zanieczyszczenia w przyszłości stwierdzono, że spalanie paliw zawierających rtęć, takich jak węgiel i olej stanowi główne źródło zanieczyszczenia wody rtęcią.
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Nanostructure of the laser-modified transition metal nanocomposites for water splitting
PublikacjaAlthough hydrogen is considered by many to be the green fuel of the future, nowadays it is primarily produced through steam reforming, which is a process far from ecological. Therefore, emphasis is being put on the development of electrodes capable of the efficient production of hydrogen and oxygen from water. To make the green alternative possible, the solution should be cost-efficient and well processable, generating less waste...
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Determination of hormones in water samples using liquid chromatography coupled with tandem mass spectrometry
PublikacjaOver the past few years, many synthetic (ethinylestradiol) and natural (estradiol,estriol, estrone) compounds present in the environment have been affecting the hormonalbalance of humans and animals. Steroid hormones are very often used for medical purposesand have high estrogenic activity what makes them endocrine disrupters. Most hormonalcompounds are released into the water as a result of their incomplete removal in wastewatertreatment...
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Providing Public Space Continuities in Post-Industrial Areas through Remodelling Land/Water Connections
PublikacjaThis article examines the problem of urban transformation strategies applied in recent years which are based on the creation of new water areas and modification of existing ones. The research is an attempt to prove that modifications of plans of water areas and forms of their borders may play an important role in achieving the best quality public spaces in post-industrial territories. The basis for demonstrating the importance...
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Chemical composition of water from roof in Gdańsk, Poland
PublikacjaThis study deals with the assessment of roof runoff waters from the region of Gdansk collected during the winter season (2007/2008). The chemical analysis includes 16 chemical variables: major ions, PAHs and PCBs measured at 3 sampling sites for 6-14 rain events. Although the data set is of limited volume the statistical data treatment using self-organizing maps (SOM) reveals the main factors controlling roof runoff water quality...
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Collagen and hyaluronic acid hydrogel in water-in-oil microemulsion delivery systems
PublikacjaThe efficacy of microemul-sion in dermal and transdermal delivery of active ingredients. Here, we assessed the water-in-oilmicroemulsion capacity to incorporate two natural polymers, i.e. collagen and hyaluronic acid withlow and high molecular weight. Systems were extensively characterized in terms of conductivity, phaseinversion studies, droplet diameter, polydispersity index and rheological properties. The results of thisresearch...
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Lead In drinking water: Adsorption method and role of zeolitic imidazolate frameworks for its remediation: A review
PublikacjaDue to various characteristics properties lead(II) metal is utilized in many applications like lead ion batteries, water pipes, ammunition and paints. For this reason, concentration of lead(II) ions in water is increasing days by days which is alarming for water pollution. Water pollution is a major problem worldwide which affects biosphere badly, and causes continuous reduction of accessible sources of fresh water and ground water, available...
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The Influence of Water and Mineral Oil on Mechanical Losses in a Hydraulic Motor for Offshore and Marine Applications
PublikacjaIn this paper, mechanical losses in a hydraulic motor supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were onducted using a special design (prototype) of a hydraulic satellite motor. The design of the satellite motor is presented. This motor was developed to supply both with water and mineral oil and features...
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THE INFLUENCE OF WATER AND MINERAL OIL ON MECHANICAL LOSSES IN THE DISPLACEMENT PUMP FOR OFFSHORE AND MARINE APPLICATIONS
PublikacjaIn this paper mechanical losses in a positive displacement pump supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were conducted using a special design (prototype) of a satellite pump. The design of the satellite pump is presented in the article. The pump features a non-circular tooth working mechanism. This pump...
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Systematic Water Uptake Energetics of Yttrium-Doped Barium Zirconate—A High Resolution Thermochemical Study
PublikacjaA combination of surface area analyzer and microcalorimetry was employed to investigate the in situ water uptake energetics and the mechanism of proton incorporation in yttrium-doped barium zirconate in the temperature range 200–400 °C. The BaZr1–xYxO3 solid solutions are made with variable yttrium content (x = 10, 20, and 30 mol %) by a controlled oxidant-peroxo synthesis method. The water uptake increases as the partial pressure...
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Contamination of water in Oliwski Stream after the flood in 2016
PublikacjaIn the article pollution of stream waters with surface runoff from an urbanized area caused by an extremely high rainfall is discussed. The analyzes were carried out after the rainfall of the depth 152 mm which took place in Gdańsk on 14th and 15th July 2016. This extreme rainfall caused urban flooding, damage of several retention ponds and pollution of surface waters. In the article the results of physical and chemical analyzes...
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The thermal effort during marine steam turbine flooding with water
PublikacjaThe work discussed an extreme case of cooling a steam turbine. The ship's steam turbine was used as an example. In marine transport units with low-speed engines dominate, however, there are also units with steam turbines. An example of analysed marine steam turbine is shown in Fig. 1. When considering the issue of cooling steam turbines, it is necessary to estimate the extreme conditions that may occur during operation of the turbine....
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Water chemistry of tundra lakes in the periglacial zone of the Bellsund Fiord (Svalbard) in the summer of 2013
PublikacjaClimate changes observed in the Arctic (e.g. permafrost degradation, glacier retreat) may have significant influence on sensitive polar wetlands. The main objectives of this paper are defining chemical features of water within six small arctic lakes located in Bellsund (Svalbard) in the area of continuous permafrost occurrence. The unique environmental conditions of the study area offer an opportunity to observe phenomena influencing...
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Analysis of drinking water
PublikacjaOpisano źródła organicznych i nieorganicznych zanieczyszczeń wody do picia w tym: lotnych związków chlorowcoorganicznych, pestycydów, wielopierścieniowych węglowodorów aromatycznych, polichlorowanych bifenyli, fenoli, kwasów chlorooctowych, aldehydów, ketonów itp. a także metody ich oznaczania. Przedstawiono schemat technik izolacji i oznaczania końcowego oraz schemat metod wykorzystujących analizę fazy nadpowierzchniowej. Opisano...
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Analysis of drinking water
PublikacjaOpisano źródła organicznych i nieorganicznych zanieczyszczeń wody do picia w tym: lotnych związków chlorowcoorganicznych, pestycydów, wielopierścieniowych węglowodorów aromatycznych, polichlorowanych bifenyli, fenoli, kwasów chlorooctowych, aldehydów, ketonów itp. a także metody ich oznaczania. Przedstawiono schemat technik izolacji i oznaczania końcowego oraz schemat metod wykorzystujących analizę fazy nadpowierzchniowej. Opisano...
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Water and food quality
PublikacjaRozdział zawiera opis podstawowych właściwości fizykochemicznych wody, rolęwody jako składnika żywności, wymagania odnośnie wody stosowanej w przemyśleżywnościowym, charakterystykę wody odpadowej, ścieków i ich neutralizację.
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Water-Lubricated Sintered Bronze Journal Bearings—Theoretical and Experimental Research
PublikacjaWater lubricated bearings are used from many years in shipbuilding, hydro power and other industries because of their advantages such as: extensive serviceable life, low coefficient of friction, longevity of shaft sleeve, good abrasion resistance, low maintenance required, unit simplicity, no danger of pollution and low price. Various types of water lubricated sliding bearings have been tested at the Technical University of Gdansk...
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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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Influence of water and mineral oil on the leaks in satellite motor commutation unit clearances
PublikacjaThe article describes the flow rates of mineral oil and water flowing, as working media, through the commutation unit of a hydraulic satellite motor. It is demonstrated that geometrical dimensions of commutation unit clearances change as a function of the machine shaft rotation angle. Methods for measuring the rate of this flow and the pressure in the working chamber are presented. The results of pressure measurements in the working...
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Study of the Flow Dynamics of Surface Water Masses in the Area of the Coastal Gulf of Gdansk
PublikacjaThe paper describes two methods of predicting the movement of small objects with surface water masses. One of the methods uses graph theory to describe the motion of water masses in port docks. The results of this study were compared to a simulation using the hydrodynamic numerical model M3D. The results obtained in a virtual environment were related to the experiments in the real world. In the coastal area of the Gulf of Gdansk,...