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Search results for: semi-adiabatic conditions
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OPERATING CONDITIONS OF SLIDE BEARINGS OF MILLS USED IN KGHM POLSKA MIEDŹ S.A.
PublicationThe paper contains the results from a tec hnical analysis of the conditions of the operation of hydrodynamic bearings supporting the drums of ore processing mills at KGHM Polska Mied ź S.A. A theoretical analysis was performed on the grounds of onsite examination and measurem ents of principal dimensions of the bearings of interest. The computer simulation covered the characteristics of the oil film in the bearings...
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What are the true volumes of SEGA tumors? Reliability of planimetric and popular semi-automated image segmentation methods
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Biostability of Tap Water—A Qualitative Analysis of Health Risk in the Example of Groundwater Treatment (Semi-Technical Scale)
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Impact of Boundary Conditions on Acoustic Excitation of EntropyPerturbations in a Bounded Volume of Newtonian Gas
PublicationExcitation of the entropy mode in the field of intense sound, that is, acoustic heating, is theoreticallyconsidered in this work. The dynamic equation for an excess density which specifies the entropy mode,has been obtained by means of the method of projections. It takes the form of the diffusion equation withan acoustic driving force which is quadratically nonlinear in the leading order. The diffusion coefficient isproportional...
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Factors Shaping the Working Environment, Living Conditions and Recreation on Board Ship
PublicationA seagoing ship is a working place, an accommodation space and a recreation area at the same time. Being exposed to harsh physical conditions, it must satisfy different requirements. The human organism and its qualities become a point of reference here; consequently, the functions and spatial arrangement and interiors of a ship must be subordinated to its needs. The organisation of the space in contemporary ships meant for human...
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Revitalization of the Narrow-Gauge Żuławy Commuter Railway and its effect on shipping conditions in the Vistula delta
PublicationThe article presents the Żuławy Access Railway and the effect of its revitalization on the change of navigational conditions in the Vistula delta. One of the problems analyzed in the article is the intersection of two different transport branches - the inland waterway and rail transport branches. A solution to the problem of their functioning is presented, without any major restrictions. Possible changes in navigational conditions...
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On delay differential equations with boundary conditions
PublicationPodano warunki na istnienie rozwiązania zagadnienia brzegowego typu opóźnionego, zakładając pewne warunki monotoniczności funkcji występującej po prawej stronie naszego zagadnienia. Pokazano, że dwa ciągi monotoniczne są zbieżne do rozwiązania dokładnego.
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Influence of boundary conditions in calibration chamber
PublicationPrzedstawiono wyniki badań modelowych penetracji w komorze kalibracyjnej z zastosowaniem modeli o różnej średnicy. Badania przeprowadzono w piasku średnio zagęszczonym i zagęszczonym przy stałej składowej poziomej naprężenia i przy składowej pionowej naprężenia w gruncie do 400 kPa. Określono wpływ warunków brzegowych na uzyskane wyniki oporu podstawy/oporu stożka lub ostrza dylatometru. Wyznaczono współczynniki korekcyjne oraz...
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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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Perception of 'Green Shipping' in the contemporary conditions
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Earthwork calculations in various field conditions
PublicationThe article characterizes the continuation of ongoing work on the MUGO computer program. The analyzes refer to the modernization of railway lines and directly to the earthwork calculations. The methodology of calculating the earthwork size in the areas of fills and cuts is discussed in detail.
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Weldability of S500MC Steel in Underwater Conditions
PublicationWet welding with the use of covered electrodes is one of the methods of underwater welding. This method is the oldest, the most economic and the most versatile. The main difficulties during underwater wet welding are: high cooling rates of the joint, the presence of hydrogen in the arc area and formation of hard martensitic structure in the weld. These phenomena are often accompanied by porosity of welds and large number of spatters,...
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Approximated boundary conditions of the equation of difussion
PublicationProblem podejmowany w pracy dotyczy warunku brzegowego w równaniach fizyki matematycznej, opisujących procesy migracji zanieczyszczeń. W szczególności skoncentrowano się na badaniu wpływu na rozwiązanie przyjmowanych w rozwiązaniach numerycznych aproksymacji ''odpływowego'' warunku brzegowego w jednowymiarowym równaniu adwekcji - dyspersji. Rozważania teoretyczne przeprowadzono w oparciu o rozwiązania analityczne oraz numeryczne...
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Differential equations with integral boundary conditions
PublicationStosuje się metodę iteracji monotonicznych opartą na dolnym i górnym rozwiązaniu. Przy jednostronnym warunku Lipschitza uzyskano pewne wyniki dotyczące rozwiązań zwyczajnych równań różniczkowych z całkowym warunkiem brzegowym. Sformułowano warunki dostateczne na istnienie jedynego rozwiązania (lub rozwiązań ekstremalnych) w pewnym segmencie. Podano przykłady ilustrujące przyjęte założenia.
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Analysis of the influence of external conditions on temperature readings in thermograms and adaptive adjustment of the measured temperature value
PublicationMeasuring human temperature is a crucial step in preventing the spread of diseases such as COVID-19. For the proper operation of an automatic body temperature measurement system throughout the year, it is necessary to consider outdoor conditions. In this paper, the effect of atmospheric factors on facial temperature readings using infrared thermography is investigated. A thorough analysis of the variation of facial temperature...
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An analysis of wind conditions at pedestrian level in the selected types of multi-family housing developments
PublicationThe following article addresses the issue of wind conditions around urban building development at pedestrian level. Factors that depend on those issues include wind comfort and air quality within urbanized spaces. The conditions specific of cities located in a temperate climate zone have been taken into account. The article is intended to identify aerodynamic phenomena characteristic of the three basic types of multi-family building...
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Evaluation of the Impact of Storage Conditions on the Biogenic Amines Profile in Opened Wine Bottles
PublicationA survey of biogenic amine (BA) profiles in opened wine bottles has been established to monitor the level of biogenic amines (BAs) in opened bottles against time and other conditions. Bottles of red and white wine were submitted to different temperatures, stopper type (screw cap, cork), and use of vacuum devices. A total of six wines made from a variety of grapes were obtained from vineyards from regions across Poland. Dispersive...
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Lighting conditions in Home Office and occupant’s perception: an international study
PublicationThe global pandemic and physical distancing restrictions are forcing us to rethink how residential buildings are used regarding the visual environment. This paper describes home office lighting conditions within different countries and continents. The aim is to define the current limitations of home offices in providing a resilient visual environment. The work was developed by a team of international experts working together on...
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Optimization of Saccharification Conditions of Lignocellulosic Biomass under Alkaline Pre-Treatment and Enzymatic Hydrolysis
PublicationPre-treatment is a significant step in the production of second-generation biofuels from waste lignocellulosic materials. Obtaining biofuels as a result of fermentation processes requires appropriate pre-treatment conditions ensuring the highest possible degree of saccharification of the feed material. An influence of the following process parameters were investigated for alkaline pre-treatment of Salix viminalis L.: catalyst concentration...
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Corrosion Resistance and Surface Bioactivity of Ti6Al4V Alloy after Finish Turning under Ecological Cutting Conditions
PublicationThe influence of cooling conditions and surface topography after finish turning of Ti6Al4V titanium alloy on corrosion resistance and surface bioactivity was analyzed. The samples were machined under dry and minimum quantity lubrication (MQL) conditions to obtain different surface roughness. The surface topographies of the processed samples were assessed and measured using an optical profilometer. The produced samples were subjected...
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Strong ellipticity conditions and infinitesimal stability within nonlinear strain gradient elasticity
PublicationWe discuss connections between the strong ellipticity condition and the infinitesimal instability within the nonlinear strain gradient elasticity. The strong ellipticity (SE) condition describes the property of equations of statics whereas the infinitesimal stability is introduced as the positive definiteness of the second variation of an energy functional. Here we establish few implications which simplify the further analysis...
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Sulfate reducing ammonium oxidation (SULFAMMOX) process under anaerobic conditions
PublicationSulfate (SO42-) can be an electron acceptor for ammonium nitrogen (NH4+) oxidation under anaerobic conditions. The process is known as sulfammox and can be a viable alternative to conventional, nitrite (NO2-) dependent, anammox. Two bacterial species, including Bacillus Benzoevorans and Brocadia Anammoxoglobus Sulfate, can perform that process. With sulfammox, an economically inefficient pre-nitration step (due to aeration) is...
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A repeated game formulation of network embedded coding for multicast resilience in extreme conditions
PublicationComputer networks and data sharing applications are vital for our current society and fundamental for any available ICT solution, so that networking is considered as one of the key critical infrastructures and its correct behavior should be always enforced, even in case of disasters or severe execution conditions. Resilience is a strongly demanding nonfunctional requirement for current computer networks, and one of the key factors...
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Working conditions in small companies in the eyes of the employees. [Warunki pracy w małych firmach w ocenie pracowników]
PublicationThe article presents the results of the study concerning the employees' awareness of working conditions. 157 employees from small production and service companies took part in the research. The research showed differences in the employees' perception of their working conditions. The employees were more often dissatisfied with working conditions than managers. A significant number of respondents (more than 75%) believe that the...
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UAV Photogrammetry under Poor Lighting Conditions—Accuracy Considerations
PublicationThe use of low-level photogrammetry is very broad, and studies in this field are conducted in many aspects. Most research and applications are based on image data acquired during the day, which seems natural and obvious. However, the authors of this paper draw attention to the potential and possible use of UAV photogrammetry during the darker time of the day. The potential of night-time images has not been yet widely recognized,...
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Modeling process of planning finished product sales volumes at industrial enterprises in modern economic conditions
PublicationThis article presents improving the existing system of planning finished products sales volumes. The influencing factors of the sales volumes in modern economic conditions have been determined: falling world oil prices, the reduction of pipe consumption in the domestic market, the global pandemic. The algorithm of planning finished products sales volumes has been constructed. Calculations based on the Holt forecasting method has...
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Evaluation of the energy efficiency of electric vehicle drivetrains under urban operating conditions
PublicationIn electric vehicles, as in hybrids vehicles, a very important factor affecting the energy efficiency of the powertrain is the ability to use the regenerative braking energy. Depending on the settings available in electric vehicles, the driver can choose different modes of operation: switch off the regenerative braking mode altogether, select the intensity of regenerative braking, or leave the control system in automatic mode....
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On jump conditions at non-material singular curves in the resultant shell thermomechanics
PublicationThe global, refined, resultant, two-dimensional (2D) balance laws of mass, linear and angular momenta, and energy as well as the entropy inequality were formulated by Pietraszkiewicz (2011) as exact implications of corresponding laws of 3D rational thermomechanics. In case of a shell with the regular base surface and all resultant surface fields differentiable everywhere on it and at any time instant, the local laws of the resultant...
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Influence of Operation Conditions on Temperature Hazard of Lithium-Iron-Phosphate (LiFePO4) Cells
PublicationThe article presents and discusses the results of research on hazard, especially temperature, for selected lithium-ion-phosphate cells operated in accordance with the manufacturer’s recommendations but used under onerous mining conditions. This applies to the performance of cells in battery sets without the application of any management system (BMS). On the basis of the obtained test results, first of all, the influence of the...
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Effect of underwater local cavity welding method conditions on diffusible hydrogen content in deposited metal
PublicationOne of the methods with great potential for applications in underwater repairs is local cavity welding. In local cavity method, cooling conditions and diffusible hydrogen amount in weld metal are nearly the same as those existed during welding in the air. This paper presents the results of literature survey and preliminary tests of the effect of local cavity welding conditions on diffusible hydrogen amount in a deposited metal....
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Modeling sequencing batch reactor operational conditions depending on oxygen concentration
PublicationSequencing batch reactors (SBR) can be used as a fill-and draw activated sludge system for wastewater treatment with considerable operating flexibility and the possibility to conduct experiments under standard conditions and extreme case scenarios. Mathematical modeling and computer simulations provide an opportunity to implement existing wastewater processes in modeling software and evaluate different modifications at low costs...
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Efficient method for octahedral NH2-MIL-125 (Ti) synthesis: Fast and mild conditions
PublicationA new hot injection method for preparing octahedral NH2-MIL-125 (Ti) was developed. This method is six times faster and conducted under milder conditions, i.e., at 120°C in a flask, and exhibits higher crystal formation efficiency than the commonly used solvothermal method while maintaining comparable structural, optical, and photocatalytic properties.
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Nonlinear strain gradient and micromorphic one-dimensional elastic continua: Comparison through strong ellipticity conditions
PublicationWe discuss the strong ellipticity (SE) conditions for strain gradient and micromorphic continua considering them as an enhancement of a simple nonlinearly elastic material called in the following primary material. Recently both models are widely used for description of material behavior of beam-lattice metamaterials which may possess various types of material instabilities. We analyze how a possible loss of SE results in the behavior...
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Multitaper-Based Post-processing of Compact Antenna Responses Obtained in Non-anechoic Conditions
PublicationThe process of developing antenna structures typically involves prototype measurements. While accurate validation of far-field performance can be performed in dedicated facilities like anechoic chambers, high cost of construction and maintenance might not justify their use for teaching, or low-budget research scenarios. Non-anechoic experiments provide a cost-effective alternative, however the performance metrics obtained in such...
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A semi-empirical method for calculation of flow boiling heat transfer coefficients for conventional channels and small diameter tubes
PublicationW pracy przedstawiono rozważania na temat modelowania dwufazowego przepływu wrzącego w kanałach konwencjonalnych i w kanałach o małej średnicy. Przedstawiono modyfikację korelacji zaproponowanej wcześniej przez J. Mikielewicza na podstawie nowych danych eksperymentalnych, uzyskanych dla kanałów o małej średnicy. Bank danych obejmował ponad 460 punktów pomiarowych dla czynników R141b, R134a, R113, R123, R12, R11 i wody. Uzyskano...
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The Effectiveness of Semi-Automated and Fully Automatic Segmentation for Inferior Alveolar Canal Localization on CBCT Scans: A Systematic Review
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Improved semi-empirical method for determination of heat transfer coefficient in flow boiling in conventional and small diameter tubes
PublicationPraca dotyczy przedstawienia poprawionego modelu umożliwiającego wyznaczanie współczynnika przejmowania ciepła w kanałach o małych średnicach jaj i tych tradycyjnych. Model zweryfikowano na 6 czynnikach chłodnuiczych uzyskując bardzo zadowalającą zgodność.
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Semi-continuous production of the anticancer drug taxol by Aspergillus fumigatus and Alternaria tenuissima immobilized in calcium alginate beads
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A concept of software extension of 3D low-PRF radar systems to 4D semi-medium-PRF radar systems
PublicationWe present a concept of software modification of three-dimensional (3D) radar systems, designed to work in the low pulse repetition frequency mode, that equips them with the ability to estimate the radial velocity and to properly measure the range of targets that are detected outside the radar’s instrumented range. Despite the fact that the proposed modifications are designed so as to require only minor changes in software, they...
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An evaluation and explanation of (in)efficiency in higher education institutions in Europe and the U.S. with the application of two-stage semi-parametric DEA
PublicationThis study uses data envelopment analysis (DEA) to evaluate the relative efficiency of 500 higher education institutions (HEIs) in ten European countries and the U.S. for the period between 2000 and 2010. Efficiency scores are determined using different input-output sets (inputs: total revenue, academic staff, administration staff, total number of students; outputs: total number of publications, number of scientific articles, graduates)...
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Physical aspect of application and usefulness of semi-Markovian processes for modelling the processes occurring in operational phase of technical objects.
PublicationW artykule zasygnalizowano przydatność teorii procesów semimarkowskich do tworzenia modeli procesów rzeczywistych, zachodzących w fazie eksploatacji różnych obiektów technicznych. Przydatność tej teorii została wykazana w wyniku przedstawienia: specyfiki procesów semimarkowskich oraz fizykalnych aspektów stosowania procesów semimarkowskich jako modeli procesów zachodzących w fazie eksploatacji wspomnianych obiektów. Specyfika została...
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An evaluation and explanation of (in)efficiency in higher education institutions in Europe and the U.S. with the application of two-stage semi-parametric DEA
PublicationIn this study the technical efficiency of number of public European and American HEIs is assessed over a decade. Efficiency scores are determined using nonparametric DEA with different input-output sets and considering different frontiers: global frontier (all HEIs pooled together), regional frontier (Europe and the U.S. having their own frontiers) and country-specific ones. The external factors affecting the degree of HEI inefficiency...
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Influence of microwave treatment conditions of GTR on physico-mechanical and structural properties of NBR/NR/GTR composites
PublicationThe increasing amount of tires used in the industry induces the researchers to find alternatives to the recycling of the end-of-life tires. Several alternatives in order to application of ground tire rubber GTR include their incorporation as a filler in composites. The main issue in this approach is the lack of compatibility between GTR and polymer matrix. In order to solve this problem the devulcanization by microwaves has been...
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Empirical verification in industrial conditions of fracture mechanics models of cutting power prediction
PublicationA comparison of experimental results obtained in the industrial conditions at a sawmill located in the Baltic Natural Forest Region (PL) and theoretical cutting power consumption forecasted with the models which include work of separation (fracture toughness) in addition to plasticity and friction has been described. In computations of cutting power consumption during rip sawing of Scots pine wood (Pinus sylvestris L.) values of...
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Optimizing FSO networks resilient to adverse weather conditions by means of enhanced uncertainty sets
PublicationThis work deals with dimensioning of wireless mesh networks (WMN) composed of FSO (free space optics) links. Although FSO links realize broadband transmission at low cost, their drawback is sensitivity to adverse weather conditions causing transmission degradation on multiple links. Hence, designing such FSO networks requires an optimization model to find the cheapest configuration of link capacities that will be able to carry...
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Positive solutions for second order impulsive differential equations involving Stieltjes integral conditions
PublicationIn this paper we investigate integral boundary value problems for fourth order differentialequations with deviating arguments.Wediscuss our problem both for advanced or delayedarguments. We establish sufficient conditions under which such problems have positivesolutions. To obtain the existence of multiple (at least three) positive solutions, we use afixed point theorem due to Avery and Peterson. An example is also included to...
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On Dynamic Boundary Conditions Within the Linear Steigmann-Ogden Model of Surface Elasticity and Strain Gradient Elasticity
PublicationWithin the strain gradient elasticity we discuss the dynamic boundary conditions taking into account surface stresses described by the Steigmann–Ogden model. The variational approach is applied with the use of the least action functional. The functional is represented as a sum of surface and volume integrals. The surface strain and kinetic energy densities are introduced. The Toupin–Mindlin formulation of the strain gradient elasticity...
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Effect of the North Atlantic Thermohaline Circulation on changes in climatic conditions and river flow in Poland
Publication: The purpose of this study is to find connections between the North Atlantic Thermohaline Circulation (NA THC), climate elements, such as cloud cover, precipitation, air temperature, sunshine duration, and relative humidity, and flow of rivers in Poland. The intensity of NA THC was characterized by the DG3L index, which was established to assess changes in the amount of heat transported by NA THC along with the transport of water...
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Effect of shielded electrode wet welding conditions on diffusible hydrogen content in deposited metal
PublicationWet welding is the most popular method of joining in water enviroment. During underwater welding, the weldability of steel is limited by the higher cooling rates and hydrogen content in weld metal. Article presents results of preliminary tests on the effects of wet welding conditions on diffusible hydrogen amount. Seven parameters were optimized using a Plackett-Burman plan to get the most relevant variables. These parameters were:...
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Experimental and Computational Analysis of the Ship Propeller in Open Water Conditions for Inclined Flow
PublicationThe paper presents the results of computational analyses simulating the open water tests of ship propeller in inclined flow. The results of computations are compared with the results of corresponding experimental analyses carried out in the towing tank of Ship Design and Research Centre (CTO S.A.). The object of the research was the model propeller identified as CP469. The aim of the study was to validate the results of numerical...