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Search results for: THERMAL EFFECTS, HYDRODYNAMIC JOURNAL BEARING, WATER-LUBRICATION, EXPERIMENTAL TESTS, NUMERICAL SIMULATIONS
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Turbulence models impact on the flow and thermal analyses of jet impingement
PublicationAccurate numerical reconstruction of heat and mass transfer processes in particular applications, such a jet impingement, is difficult to obtain even with the use of modern computational methods. In the proposed paper, the flow and thermal phenomena occurring during single minijet impingement on the flat, concave and convex, heated surfaces were considered. Problem of impingement on non-flat surface, still not common and purely...
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Artificial Thermal Ageing of Polyester Reinforced and Polyvinyl Chloride Coated Technical Fabric
PublicationArchitectural fabric AF9032 has been subjected to artificial thermal ageing to determine changes of the material parameters of the fabric. The proposed method is based on the accelerated ageing approach proposed by Arrhenius. 300 mm x 50 mm samples were cut in the warp and fill directions and placed in a thermal chamber at 80 °C for up to 12 weeks or at 90 °C for up to 6 weeks. Then after one week of conditioning at ambient temperature,...
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Macromodels for efficient FEM simulations of waveguides and resonators
PublicationThis paper introduces a novel technique for enhancing the efficiency of the finite element method (FEM) by incorporating special modules, called macromodels, into the standard eigenvalue formulation. The number of unknowns in the separated macromodel subdomain can be significantly reduced by orthogonal projection, using the efficient nodal order reduction algorithm. The idea of macromodels implementation is demonstrated on a simple...
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First tests of water lubricated propeller shaft bearings = Wstępne badania zespołu smarowanych wodą łożysk okrętowego wału śrubowego
PublicationW pierwszej części referatu zaprezentowano nowe stanowsko badawcze przy pomocy którego można badać smarowane wodą łożyska wału śrubowego. W drugiej części pracy przedstawiono uzyskane wyniki pomiarów oporów ruchu i trajektorii osi wału.
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Experimental Verification of Storm Sewer Transient Flow Simulation
PublicationThe paper focuses mainly on laboratory investigations of transient and transcritical flow in a single pipe of a sewer system. The aim of this paper is to present a comparison between pressure values calculated by an improved McCormack scheme and those measured at the hydraulic laboratory of the Gdansk University of Technology, which were observed inside a pipe in an experiment for water flow with pressurization. The analysis proves...
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Dynamics analysis of footbridge mode shapes the s8 expressway on the basis of the results of in situ tests
PublicationNon-destructive diagnostics for structure may use dynamic measurements realized during vibrations of a facility induced by dynamic environmental impact, enforced by the use of inductors or impulse impact. Dynamic tests and the analysis were undertaken for a footbridge situated over the expressway S8. The studies in situ allowed for dynamic characteristics to be determined: frequency, shape modes and damping for respective frequency...
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Experimental research on technical fabric of the Forest Opera Roof in Sopot
PublicationThe experimental analysis of the technical fabric Valmex is presented. The study involves uniaxial tensile, cyclic, rheological and biaxial tests. Some of the main differencies between two types of the analysed material have been identified. Mechanical properties of the textile have been modeled by the viscoelastic standard model with quite good effect.
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Updating Finite Element Model of a Wind Turbine Blade Section Using Experimental Modal Analysis Results
PublicationThis paper presents selected results and aspects of themultidisciplinary and interdisciplinary research oriented for the experimental and numerical study of the structural dynamics of a bend-twist coupled full scale section of awind turbine blade structure.Themain goal of the conducted research is to validate finite elementmodel of themodified wind turbine blade section mounted in the flexible support structure accordingly to the...
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Influence of nanoparticle concentration on convective heat transfer of water-Al2O3 nanofluids inside horizontal tubes
PublicationNanofluids came to be seen as a new generation of coolants, especially in single-phase systems. Conducted experiments indicate that the increase in thermal conductivity is not the only reason for the intensification of heat transfer when using nanofluids. Preliminary results of the experimental investigation of the forced convection heat transfer of water-Al2O3 nanofluids inside stainless steel tube with 8 mm internal diameter...
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Metrological analysis of surface quality aspects in minimum quantity cooling lubrication
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Measurements of surface roughness of heads of human hip joints in lubrication aspects
PublicationW niniejszej pracy przedstawiono wyniki pomiarów chropowatości chrząstki stawowej na powierzchniach głów kostnych stawu biodrowego człowieka. Pomiarów dokonano przy pomocy czujników mechanicznych i laserowych. Praca zawiera wyniki analizy statystycznej.
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Non-Newtonian lubrication of human hip joint for unsteady impulsive motion
PublicationTematem niniejszej pracy są parametry smarowania lepkosprężystą cieczą synowialną stawu biodrowego człowieka w czasie kilku, kilkunastu a nawet kilkudziesięciu mikrosekund po doznanym urazie. W niniejszej pracy rozpatruje się urazy wywołujące zmniejszenie lub zwiększenie wysokości i zmiany kształtu szczeliny stawu, które to zmiany po pewnym określonym czasie po doznanym urazie mogą zanikać. W konsekwencji takich urazów i to w...
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A New Approach of Solidification Analysis in Modular Latent Thermal Energy Storage Unit Based on Image Processing
PublicationThe solidification process of RT18HC in a cylindrical shell and tube storage unit has been studied using a new methodology based on image processing. The main idea of the algorithm is to label the region of solidification and use statistical functions to calculate the dimensions of the solidification front over time. Said analysis includes two methods. The first method is to measure the solid fraction changes during solidification....
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The nonlinear effects of sound in a liquid with relaxation losses
PublicationThe 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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Correlated Particle Motion and THz Spectral Response of Supercritical Water
PublicationMolecular dynamics simulations of supercritical water reveal distinctly different distance-dependent modulations of dipolar response and correlations in particle motion compared to ambient conditions. The strongly perturbed H-bond network of water at supercritical conditions allows for considerable translationaland rotational freedom of individual molecules. These changes give rise to substantially different infrared spectra and...
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FPGA Based Real Time Simulations of the Face Milling Process
PublicationThe article presents a successful implementation of the milling process simulation at the Field-Programmable Gate Array (FPGA). By using FPGA, very rigorous Real-Time (RT) simulation requirements can be met. The response time of the FPGA simulations is significantly reduced, and the time synchronization is better than in a typical RT system implemented in software. The FPGA-based approach is characterized by enormous flexibility...
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Entropy of water calculated from harmonic approximation: estimation of the accuracy of method
PublicationSome molecular dynamics simulations were performed for liquid TIP4P and SPC water at a constant density (1.00 g/cm(3)) and within the temperature range of 5-90 degrees C. By using harmonic approximation, both the entropy of water S-H and the specific heat c(v) were calculated, and the results were compared to literature data. It was found that harmonic approximation overestimates absolute entropy of TIP4P water by 5.6 J/mol K (similar...
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Prediction of ship resistance with the use of Full-scale CFD simulations
PublicationIn recent years, the IMO has introduced new regulations to reduce the negative impact of ships on the natural environment. A particularly important step forcing technological innovations is the increasing requirement of ship energy efficiency. It is expressed by the Energy Efficiency Design Index (EEDI). Another important step towards green shipping is rising the required quality of fuel used for propulsion, so called Tier limits....
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Thermal Imaging in Wound Healing Diagnostics
PublicationResults of a project searching for objective, quantitative evaluation of postoperative wound healing in cardiosurgery are presented. We propose simple thermal models of the healing processes after cardiosurgery interventions as objective descriptors allowing classification of patients for extraction and following recovery at home or for prolonged treatment in a hospital. Classification of healing as the normal process or as a process...
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Hydrological indicators of water zones in inundation, historical water levels, and forcing data for the 1881-2099 period in the lower Biebrza valley
Open Research DataThis data set contains hydrological (1) indicators of water source extents in the Biebrza River floodplain (NE Poland) simulated using an integrated hydrological model (IHM), (2) forcing data for the IHM, and (3) water levels in the Osowiec station from the period 1881-1910.
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RADIATION EFFECTS AND DEFECTS IN SOLIDS
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Effects of subfilter velocity modelling on dispersed phase in LES of heated channel flow
PublicationA non-isothermal turbulent flow with the dispersed phase is modelled using the Large Eddy Simulation (LES) approach for fluid, one-way coupled with the equations of point-particle evolution. The channel is heated at both walls and isoflux boundary conditions are applied for fluid. Particle velocity and thermal statistics are computed. Of particular interest are the r.m.s. profiles and the probability density function of particle...
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Research report (Health Effects Institute)
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Experimental database of 3D lattice structure scaffolds testing
Open Research DataDataset contains results of validation (experimental testing) of 3D lattice scaffolds proposed in the paper "Mathematical approach to design 3D scaffolds for the 3D printable bone implant". There are presented three series of experimental testing for each of seven tested scaffolds:
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Comparison of the tests for equivalence of the measurement methods for measurement of PM10 dust in ambient air
PublicationThe paper presents the motives for conducting the equivalence tests and the reasons of discrepancies between the results of PM10 dust concentration obtained via the reference method and the methods based on 'on-site' measurement. The reference and non-reference methods of measurement of PM10 dust concentration in air have been discussed. Field tests for equivalence, following the Polish standard and the European Union (EU) guidelines,...
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Constant vs. Variable Efficiency of Electric Drive in Train Run Simulations
PublicationTrain run simulations, which focus on various power- and energy-oriented aspects, should reflect the losses in the electric powertrain. In general, the powertrain efficiency varies with respect to load and speed. Including this relation in simulation requires knowledge about detailed drivetrain parameters, which are often unavailable. This paper verifies the possibility to approximate the drivetrain efficiency in train run simulations...
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Balance errors generated by numerical diffusion in the solution of non-linear open channel flow equations
PublicationThe paper concerns the untypical aspect of application of the dissipative numerical methods to solve nonlinear hyperbolic partial differential equations used in open channel hydraulics. It is shown that in some cases the numerical diffusion generated by the applied method of solution produces not only inaccurate solution but as well as a balance error. This error may occur even for an equation written in the conservative form not...
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Nutrient recovery from deammonification effluent in a pilot study using two-step reject water treatment technology
PublicationThe aim of this study was to assess the possibility of phosphorus and nitrogen recovery from the liquid fraction of digestates (reject water) pilot study using a two-step technology, where the precipitation of biogenic compounds in the form of magnesium ammonium phosphate (struvite) will be preceded by a deammonification process. The tests confirmed the possibility of nutrient recovery from deammonification effluent. A removal...
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Thermal stabilization and permanent deformation resistance of LWA/PCM-modified asphalt road surfaces
PublicationThis paper presents the results of attempts at reducing the problem of solar overheating of asphalt road pavement surfaces, resulting in weakening and accelerated destruction of the aforementioned structures. To protect pavement surfaces against periodic overheating, standard asphalt mixture AC 16 W 35/50, used for binder course, has been modified by replacing one of the aggregate fractions from the mineral mixture with lightweight...
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Numerical Study of Turbulent Flow and Heat Transfer of Nanofluids in Pipes
PublicationIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (Reynolds number between 6000 and 12000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
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Thermal behavior of (NH4)V4O10xH2O
Open Research DataThe DataSet contains the results of the thermal behavior of the (NH4)V4O10xH2O obtained by the hydrothermal method using different precursors: microstructured (commercially available) or nanostructured. The information about samples synthesis is described in the Materials.
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Calculating the Partition Coefficients of Organic Solvents in Octanol/Water and Octanol/Air
PublicationPartition coefficients define how a solute is distributed between two immiscible phases at equilibrium. The experimental estimation of partition coefficients in a complex system can be an expensive, difficult, and time-consuming process. Here a computational strategy to predict the distributions of a set of solutes in two relevant phase equilibria is presented. The octanol/water and octanol/air partition coefficients are predicted...
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Determination of organophosphorus and organonitrogen pesticides in water samples
PublicationPesticides are among the most dangerous environmental pollutants because of their stability, mobility and long-term effects on living organisms. Their presence in sources of drinking water, essential to life, is a particular danger. In water, these compounds can undergo transformations, leading to the production of substances of even greater toxicity. Legal regulations are in force, stipulating the highest permissible level of...
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Model of optical phantoms thermal response upon irradiation with 975 nm dermatological laser
PublicationWe have developed a numerical model describing the optical and thermal behavior of optical tissue phantoms upon laser irradiation. According to our previous studies, the phantoms can be used as substitute of real skin from the optical, as well as thermal point of view. However, the thermal parameters are not entirely similar to those of real tissues thus there is a need to develop mathematical model, describing the thermal and...
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Pyrrole bearing diazocrowns: Selective chromoionophores for lead(II) optical sensing
PublicationDiazocrowns of 18-, 21- and 23-membered rings with pyrrole residue as a part of macrocycle were for the first time used as chromoionophores in lead(II) selective optodes. Sensing properties of optodes depend on the type of macrocycle, namely its size and the type of linker: oligoether or hydrocarbon chain. The best results were obtained for optode bearing 18-membered crown with oligoether linker showing linear response range of...
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Ewa Marjańska dr inż.
PeopleEwa Marjańska works as an assistant professor at the Gdańsk University of Technology, at the Faculty of Management and Economics. She received her doctorate in the field of commodity science. Her scientific interests focus primarily on the methods of quantitative measurements of quality, including food quality analysis and quality management systems, as well as on the quality of higher education. She is the author of papers published...
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Influence of type of material on performance of hydraulic components in thermal shock conditions
PublicationDuring the start-up of a hydraulic system in low ambient temperatures an incorrect operation may occur. The principles and conditions of safely operating hydraulic driven machines and devices are essential to designers and operators. For this reason the author of this article has conducted a series of tests on hydraulic components and systems in thermal shock conditions (cooled-down components were supplied with hot working medium)....
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Journal of Numerical and Applied Mathematics
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IMA JOURNAL OF NUMERICAL ANALYSIS
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Journal of Applied and Numerical Optimization
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SIAM JOURNAL ON NUMERICAL ANALYSIS
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Thermal properties of poly(vinyl chloride)/polyurethane blends
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Evaluation of a Small Inland Ferry’s Energy Requirements from the Acceleration Stage of Towing Tank Model Tests
PublicationComputing the power required to meet a ship’s operational needs is one of the most important tasks in naval design. The power required to propel a vessel is directly related to the resistance the hull experiences as it moves through the water. The conventional method of determining a ship’s resistance involves towing tank tests of ship models at a fixed speed; however, for short-range vessels, where constant speed is not the primary...
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The Impact of Experimental Temperature and Water Level Manipulation on Carbon Dioxide Release in a Poor Fen in Northern Poland
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Effect of surface roughness on thermal-hydraulic characteristics of plate heat exchanger
PublicationIn the paper the experimental analysis of passive heat transfer intensification in the case of modeled plate heat exchanger is conducted. The plate heat exchanger is chosen for the analysis because this kind of heat exchangers could be prospectively applied in the ORC systems, however other areas or application are equally possible. The experimental setup was assembled at the Department of Energy and Industrial Apparatus of Gdansk...
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Bearing testing machine with rotating load vector.
PublicationW pracy przedstawiono koncepcję konstrukcyjną i prototyp stanowiska badawczego z wirująca reakcją łożyskową przeznaczonego do testowania wytrzymałości zmęczeniowej warstw ślizgowych w łożyskach poprzecznych. Konstrukcja i przeznaczenie maszyny zbudowanej w laboratorium tribologicznym Politechniki Gdańskiej jest zgodna z zaleceniami normy ISO 7905. Przeanalizowano zalety i wady maszyny badawczej o takim wzorcu obciążenia testującego.
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Experimental and numerical investigation of crosstalk effect in coupled coplanar waveguides - part i: bi-mode coupled line representation
PublicationW pracy przedstawiono analizę zjawiska przesłuchu w strukturze sprzężonych falowodów koplanarnych. Analiza wykorzystując metodę przestrzeni widmowej i bazując na dwurodzajowym modelu pary linii sprzężonych uwzględnia efekty dyspersji obserwowane w zakresie wysokich częstotliwośći. Przedyskutowano zagadnienie sposobu definicji impedancji charakterystycznych dla prowadzonych rodzajów pola. Wyniki modelowania numerycznego potwierdzono...
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Advanced Experimental and Numerical Analysis of Behavior Structural Materials Including Dynamic Conditions of Fracture for Needs of Designing Protective Structures
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Jan Franz dr hab.
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Experimental test of nonclassicality with arbitrarily low detection efficiency
PublicationWe theoretically introduce and experimentally demonstrate the realization of a nonclassicality test that allows for arbitrarily low detection efficiency without invoking an extra assumption of independence of the devices. Our test and its implementation is set in a prepare-and-measure scenario with an upper limit on the classical communication capacity of the channel through which the systems are communicated. The essence for our...