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Search results for: THERMAL BOUNDARY CONDITIONS
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On the well posedness of static boundary value problem within the linear dilatational strain gradient elasticity
PublicationIn this paper, it is proven an existence and uniqueness theorem for weak solutions of the equilibrium problem for linear isotropic dilatational strain gradient elasticity. Considered elastic bodies have as deformation energy the classical one due to Lamé but augmented with an additive term that depends on the norm of the gradient of dilatation: only one extra second gradient elastic coefficient is introduced. The studied class...
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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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Effect of crystallinity on structural, thermal, and in vitro dissolution properties of Na2O-CaO-Nb2O5/MgO-P2O5 glass-ceramics
PublicationThe impact of the crystallinity on structural, thermal, and in vitro dissolution properties were examined for Na2O- CaO-Nb2O5/MgO-P2O5 glasses/glass-ceramics. Glass-ceramics were synthesized via a spontaneous crystallization process. The Nb content in the materials increased with melting temperature, furthermore, the crystallinity is proportional to the Nb content. The presence of crystalline niobates and phosphates is confirmed...
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Implementation of the FOPID Algorithm in the PLC Controller - PWR Thermal Power Control Case Study
PublicationIn the paper authors describe proposition of design and verification procedures of the discrete Fractional Order PID (FOPID) algorithm for control of the Pressurized Water Reactor (PWR) thermal power near its nominal operating point. The FOPID algorithm synthesis consists of: off-line optimal tunning of its parameters in continuous time-domain with LQ (Linear Quadratic) performance index and simplified models of nuclear reactor...
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Effect of Thermal Treatment and Erosion Aggressiveness on Resistance of S235JR Steel to Cavitation and Slurry
PublicationS235JR steel is used in many applications, but its resistance to the erosion processes has been poorly studied. To investigate this resistance, cavitation, and slurry erosion tests were conducted. These tests were carried out at different erosion intensities, i.e., different flow rates in the cavitation tunnel with a system of barricades and different rotational speeds in the slurry pot. The steel was tested as-received and after...
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Multiple Reprocessing of Conductive PLA 3D-Printing Filament: Rheology, Morphology, Thermal and Electrochemical Properties Assessment
PublicationAdditive manufacturing technologies are gaining more and more attention, resulting in the development or modification of 3D printing techniques and dedicated materials. On the other hand, economic and ecological aspects force the industry to develop material recycling strategies. In this work, the multiple reprocessing of a commercially available PLA conductive composite with carbon black filler, dedicated to 3D printing, was investigated....
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Novel Cast Polyurethanes Obtained by Using Reactive Phosphorus-Containing Polyol: Synthesis, Thermal Analysis and Combustion Behaviors
PublicationPhosphorus-containing polyol applications in polyurethane synthesis can prevent volatilization of flame retardants and their migration on the surface of a material. In this work, novel cast polyurethanes were prepared by a one-step method with the use of different amounts of phosphorus-containing polyol, 4,4′–diphenylmethane diisocyanate and 1,4-butanediol. The chemical structure, thermal, physicochemical and mechanical properties...
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Study on effective front region thickness of PCM in thermal energy storage using a novel semi-theoretical model
PublicationThermal energy storage in mobile applications, particularly battery of electric vehicles, is currently gaining a lot of importance. In this paper, a semi-theoretical time-dependent mathematical model of the phase change in a double shell thermal energy storage module has been developed where the inner tube is a heat exchange surface. An effective front region thickness for the melting and solidification process has been studied....
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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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Thermal Image Processing for Respiratory Estimation from Cubical Data with Expandable Depth
PublicationAs healthcare costs continue to rise, finding affordable and non-invasive ways to monitor vital signs is increasingly important. One of the key metrics for assessing overall health and identifying potential issues early on is respiratory rate (RR). Most of the existing methods require multiple steps that consist of image and signal processing. This might be difficult to deploy on edge devices that often do not have specialized...
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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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Inter-laboratory proficiency tests in measuring thermal insulation and evaporative resistance of clothing using the Newton-type thermal manikin
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Thermal analysis and experimental verification of permanent magnet synchronous motor by combining lumped-parameter thermal networks with analytical method
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Globalized Simulation-Driven Miniaturization of Microwave Circuits by Means of Dimensionality-Reduced Constrained Surrogates
PublicationSmall size has become a crucial prerequisite in the design of modern microwave components. Miniaturized devices are essential for a number of application areas, including wireless communications, 5G/6G technology, wearable devices, or the internet of things. Notwithstanding, size reduction generally degrades the electrical performance of microwave systems. Therefore, trade-off solutions have to be sought that represent acceptable...
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Analysis of the Water Level Variation in the Polish Part of the Vistula Lagoon (Baltic Sea) and Estimation of Water Inflow and Outflow Transport through the Strait of Baltiysk in the Years 2008–2017
PublicationThe Vistula Lagoon is located in both Poland and Russia along the southern coast of the Baltic Sea. It is connected to the Baltic Sea in the Russian part by the Strait of Baltiysk. The purpose of the paper is to identify the dominant factors underlying the water level variation mechanism at Tolkmicko in the Vistula Lagoon, revealed by a statistical analysis of the measured data and a discussion on the inflow and outflow transport...
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Impact of climate change on groundwater recharge in shallow young glacial aquifers in northern Poland
PublicationWe investigated the influence of climate change in the period 1951–2020 on shallow aquifers in the Brda and Wda outwash plains (Pomeranian Region, Northern Poland). There was a significant temperature rise (0.3 °C/10 years), which accelerated after 1980 (0.66 °C/10 years). Precipitation became increasingly irregular – extremely rainy years occurred right after or before extremely dry years, and intensive rainfall events became...
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Globalized Knowledge-Based Simulation-Driven Antenna Miniaturization Using Domain-Confined Surrogates and Dimensionality Reduction
PublicationDesign of contemporary antenna systems encounters multifold challenges, one of which is a limited size. Compact antennas are indispensable for the new fields of application such as inter-net of things or 5G/6G mobile communication. Still, miniaturization generally undermines elec-trical and field performance. When attempted through numerical optimization, it turns into a constrained problem with costly constraints requiring electromagnetic...
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On description of periodic magnetosonic perturbations in a quasi-isentropic plasma with mechanical and thermal losses and electrical resistivity
PublicationMagnetosonic periodic perturbations in a uniform and infinite plasma model are considered. Damping due to compressional viscosity, electrical resistivity, and thermal conduction are taken into account, as well as some heating–cooling function, which may destroy the isentropicity of wave perturbations. The wave vector forms arbitrary angle h with the equilibrium straight magnetic field, and all perturbations are functions...
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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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Structural, thermal and energetic characteristics of synthetic active carbons prepared on the basis of ion-exchange resin Amberlite IRC 84
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Heteroleptic cadmium(II) complex, potential precursor for semiconducting CdS layers. Thermal stability and non-isothermal decomposition kinetics
PublicationW ramach pracy zweryfikowano stabilność termiczną [Cd{SSi(OBut)3}(S2CNEt2)]2 - potencjalnego prekursora do otrzymywania warstw półprzewodnikowych CdS. Równocześnie przeprowadzono analizę kinetyki rozkładu za pomocą różnych metod izokonwersyjnych zaproponowanych przez Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose i Friedmanna w wyniku czego wyznaczono całkowity tryplet kinetyczny dla omawianego kompleksu.
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Dynamic mechanical properties and thermal degradation process of the compositions obtainedfrom unsaturated poly(ester urethanes) cross-linked with styrene
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Thermal behavior of the highly luminescent poly(3-hydroxybutyrate):Eu(tta)3(H2O)2 red-emissive complex
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Nanosized carbon black as synergist in PP/POE-MA/IFR system for simultaneously improving thermal, electrical and mechanical properties
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A Target Information Display for Visualising Collision Avoidance Manoeuvres in Various Visibility Conditions
PublicationThe paper introduces a new approach to displaying information on targets. The proposed display visualises three types of information: targets’ motion parameters (typical for target tracking), combinations of own course and speed which collide with those targets (typical for Collision Threat Parameters Area display by Lenart (1983)) and combinations of own course and speed which are not compliant with COLREGS in this case (based...
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Automatic sound source localization in disturbing conditions using acoustic vector sensors
PublicationA concept, practical realization and applications of a passive acoustic radar to automatic localization and tracking of sound sources in disturbing conditions were presented in the paper. The device consists of the new kind of multichannel miniature sound intensity sensors and a group of digital signal processing algorithms. The sensitivity of the realized acoustic radar was examined in free sound field. Several kinds of sound...
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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...
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Minimization of a ship's magnetic signature under external field conditions using a multi-dipole model
PublicationThe paper addresses the innovative issue of minimizing the ship's magnetic signature under any external field conditions, i.e., for arbitrary values of ambient field modulus and magnetic inclination. Varying values of the external field, depending on the current geographical location, affect only the induced part of ship's magnetization. A practical problem in minimizing the ship signature is separating permanent magnetization...
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Effect of crystallization process at cryogenic conditions on the functional properties of the SUPERSTON alloy used in production the ship's propellers
PublicationThe purpose of this paper is to show results of laser treatment at cryogenic conditions of the SUPERSTON alloy used for ship's propellers. That modification process ought to bring beneficial changes of microstructure and residual stresses in the surface layer. During the laser remelting at cryogenic conditions the microstructure changes significantly. This is related to synergistic effects of the solidification rate, phase transformations...
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Thermal efficiency investigations on the self-ignition test engine fed with marine low sulfur diesel fuels
PublicationWithin the article an issues of implementing the new kinds of marine diesel fuels into ships’ operation was described taking into ac-count restrictions on the permissible sulphur content introduced by the International Maritime Organization. This is a new situation for ship owners and fuel producers, which forces the necessity to carry out laboratory research tests on especially adapted engine stands. How to elaborate the method...
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Thermal decomposition of acrylic pressure-sensitive adhesives
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The dynamic thermal properties of aerogel-incorporated concretes
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Impact of the medical clothing on the thermal stress of surgeons
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Thermal and calorimetric investigations of titania–silica composites
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Intelligent thermal imaging camera with network interface
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The effect of sludge thermal disintegration on quality of effluents
PublicationDezintegracja osadów ściekowych prowadzona jest w celach intensyfikacji procesu fermentacji metanowej oraz poprawy odwadnialności osadów ściekowych. Przedstawiono zmiany jakości cieczy nadosadowej osadów ściekowych poddanych procesowi termicznej dezintegracji. Określono zmiany wartości chemicznego zapotrzebowania na tlen oraz stężenia azotu amonowego, białka, fosforanów oraz lotnych kwasów tłuszczowych.
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Thermal analysis of bis(tetraethylammonium) tetrachloroferrate(II)
PublicationBadano dekompozycję termiczną związków bis(tetraethylammonium) tetrachloroferrate(II). Stosowano następujące metody badawcze: TG-FTIR, TG-MS i DTA. Pomiary przeprowadzono w atmosferze obojętnej w zakresie temperatur od 293 K do 1073 K. Stałe produkty dekompozycji identyfikowano metodą spektroskopii w podczerwieni, spektroskopii Mössbauera oraz metodą dyfrakcji promieniowania rentgenowskiego. Przedyskutowano wpływ stopnia utlenienia...
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Photoinduced and thermal oxidation of rapeseed and sunflower oils
PublicationCelem prezentowanych badań było porównanie stabilności oksydatywnej olejów rzepakowych i słonecznikowych. Na etapie przyspieszania utleniania zastosowano promieniowanie UV. Po naświetlaniu lotne produkty utlenienia były izolowane z fazy nadpowierzchniowej przy pomocy mikroekstrakcji do fazy stacjonarnej HS-SPME(włókno DVB/CAR/PDMS) i oznaczane z zastosowaniem chromatografii gazowej z detektorem płomieniowo-jonizacyjnym (GC/FID)....
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Performance Analysis of A Photovoltaic-Thermal Integrated System
PublicationW artykule przedstawiono analizę energetyczną i egzergetyczną układu zintegrowanego PV/T. Straty egzergii występują zawsze w układach, w których procesy zachodzą ze zmianą temperatury i są proporcjonalne do wzrostu entropii systemu. Analiza egzergetyczna pozwala zlokalizować miejsce, wielkość i źródło termodynamicznej nieefektywności i ta informacja, trudna do pozyskania w inny sposób (np. przez analizę energetyczną) jest przydatna...
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PVT - hybrid photovoltaic - thermal solar systems
PublicationPVT - to urządzenia, łączące ze sobą funkcje modułu fotowoltaicznego i kolektora słonecznego, w którym rolę absorbera pełni moduł ogniw fotowoltaicznych. Umożliwia to otrzymywanie z tej samej powierzchni pokrycia dachu lub fasady budynku uzyskiwanie jednocześnie energii elektrycznej i cieplnej. Uzyskiwane ciepło jest ciepłem niskotemperaturowym. Poszczególne rozwiązania systemów PVT można scharakteryzować ze względu na: różną liczbę...
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Thermal lenses caused by any acoustic source.
PublicationNieliniowe straty energii fali akustycznej doprowadzają do powstania obszarów ogrzanych, to znaczy obszarów o innej prędkości fali akustycznej niż pozostała przestrzeń. Soczewki termiczne wywoływane przez propagację fal akustycznych okresowych i nieokresowych są rozpatrywane. Przedstawiono ilustrację obliczeń numerycznych.
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Multilayer thermal model of healty and burned skin
PublicationW pracy przedstawiono spójny model cieplny skóry wraz z tkankami podskórnymi, na podstawie pomiarów "in vitro" na świni domowej. Model uwzględnia rozkład temperatury, przewodności cieplnej oraz efuzyjności i dyfuzyjności cieplnej w funkcji głębokości, zarówno dla skóry zdrowej jak i oparzonej.
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The solvent-free thermal dehydration of hexitols on zeolites
PublicationPodczas termicznej dehydratacji heksytoli w obecności zeolitów otrzymano szereg produktów zachodzących zarówno z inwersją lub retencją konfiguracji przy asymetrycznych atomach węgla. Produkty rozdzielano i identyfikowano przy pomocy chromatografii i spektroskopii NMR. 1,4:3,6-dianhydroiditol scharakteryzowano przy pomocy rentgenowskiej analizy strukturalnej.
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Thermal stability of the cobalt base clad layers
PublicationBadano wpływ długotrwałego oddziaływania temperatury na mikrostrukturę i własności mechaniczne warstw napawanych laserowo wykonanych ze stopów na bazie kobaltu zawierających chrom i wolfram. Stopy te są przewidywane do zastosoania na przylgnie zaworów wydechowych silników diesla.
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Magneto-thermal convection of low concentration nanofluids
PublicationThe main aim of this paper was to analyze possible utilization of the low concentration nanofluids and the magnetic field to enhance heat transfer. The studied fluids were based on water with an addition of copper particles (40-60 nm diameter). They belonged to the diamagnetic group of materials. As a first attempt to stated target the analysis of enclosure placed in the maximal value of square magnetic induction gradient was carried...
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Thermal-Humidity Parameters of 3D Printed Wall
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Style Transfer for Detecting Vehicles with Thermal Camera
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Thermal stability of expanded perlite modified by mullite
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Thermal ablation modeling via bioheat equation
PublicationWe consider Pennes’ bioheat equation and discuss an implicit numerical scheme which has better stability properties than other approaches. Our discussion concerns Carthesian geometry problems, however it carries over to spherical geometry models and more complicated shapes.