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Experimental and Computational Analysis of the Ship Propeller in Open Water Conditions for Inclined Flow
PublikacjaThe 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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Automatic sound source localization in disturbing conditions using acoustic vector sensors
PublikacjaA 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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Biomechanics of the medial meniscus in the osteoarthritic knee joint
PublikacjaBackground. Increased mechanical loading and pathological response of joint tissue to the abnormal mechanical stress can cause degradation of cartilage characteristic of knee osteoarthritis (OA). Despite osteoarthritis is risk factor for the development of meniscal lesions the mechanism of degenerative meniscal lesions is still unclear. Therefore, the aim of the study is to investigate the influence of medial compartment knee OA...
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A study of a compact high-efficiency zero-emission power plant with oxy-fuel combustion
PublikacjaThis paper discusses the application of global trends in gas cycles technology using oxy-fuel combustion. This is followed by a demonstration of a design solution for a new cycle with two enhanced energy-converting devices, namely a wet combustion chamber and a spray-ejector condenser. The proposed gas and steam cycle unit is contained within a single turbine, whose benefits combine those offered by gas turbines (high inlet temperatures)...
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Integrated Experimental and Theoretical Approach for Efficient Design and Synthesis of Gold-Based Double Halide Perovskites
PublikacjaApplied cutting-edge electronic structure and phonon simulations provide a reliable knowledge about the stability of perovskite structures and their electronic properties, which are crucial for design of effective nanomaterials. Gold is one of the exceptional elements, which can exist both as a monovalent and a trivalent ion in the B site of a double perovskite such as A2BI BIIIX6. However, until now, electronic properties of Cs2AuI AuIIIX6...
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Fast collaborative graph exploration
PublikacjaWe study the following scenario of online graph exploration. A team of k agents is initially located at a distinguished vertex r of an undirected graph. At every time step, each agent can traverse an edge of the graph. All vertices have unique identifiers, and upon entering a vertex, an agent obtains the list of identifiers of all its neighbors. We ask how many time steps are required to complete exploration, i.e., to make sure...
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ARTIFICIAL MODEL IN THE ASSESSMENT OF THE ALGORITHM OF OBJECTS RECORDED BY LASER SCANNING SHAPE DETECTION (ALS/TLS)
PublikacjaBrief description of the study and used methods. Brief description of the study and used As part of the preparatory work aimed to create the application solution allowing for the automation of searching objects in data, obtained in the scanning process using ALS (Airborne Laser Scanning) or TLS (Terrestrial Laser Scanning), the authors prepared a artificial (synthetic, theoretical) model of space, used for the verification of operation...
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Brief Announcement: Energy Constrained Depth First Search
PublikacjaDepth first search is a natural algorithmic technique for constructing a closed route that visits all vertices of a graph. The length of such route equals, in an edge-weighted tree, twice the total weight of all edges of the tree and this is asymptotically optimal over all exploration strategies. This paper considers a variant of such search strategies where the length of each route is bounded by a positive integer B (e.g. due...
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Fast Collaborative Graph Exploration
PublikacjaWe study the following scenario of online graph exploration. A team of k agents is initially located at a distinguished vertex r of an undirected graph. At every time step, each agent can traverse an edge of the graph. All vertices have unique identifiers, and upon entering a vertex, an agent obtains the list of identifiers of all its neighbors. We ask how many time steps are required to complete exploration, i.e., to make sure...
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Experimental and Numerical Study on Dynamics of Two Footbridges with Different Shapes of Girders
PublikacjaThe paper presents the experimental and numerical results of the dynamic system identification and verification of the behavior of two footbridges in Poland. The experimental part of the study involved vibration testing under different scenarios of human-induced load, impulse load, and excitations induced by vibration exciter. Based on the results obtained, the identification of dynamic parameters of the footbridges was performed...
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Minimization of a ship's magnetic signature under external field conditions using a multi-dipole model
PublikacjaThe 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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Structural changes of bacterial cellulose due to incubation in conditions simulating human plasma in the presence of selected pathogens
PublikacjaBacterial nanocellulose (BNC) is a natural biomaterial with a wide range of medical applications. However, it cannot be used as a biological implant of the circulatory system without checking whether it is biodegradable under human plasma conditions. This work aimed to investigate the BNC biodegradation by selected pathogens under conditions simulating human plasma. The BNC was incubated in simulated biological fluids with or...
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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
PublikacjaThe 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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The Effect of Welding Conditions on Mechanical Properties of Superduplex Stainless Steel Welded Joints
PublikacjaThe tests results of superduplex stainless steel welded joints made with a different heat input, using automatic submerged arc welding (SAW) and semi-automatic flux-cored arc welding (FCAW) have been presented. Metallographic examinations, the measurements of the ferrite content, the width of the heat affected zone (HAZ) and the hardness of the welds in characteristic areas have been performed. Significant differences in the amount of...
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Soil-structure interaction effects on modal parameters of office buildings with different number of stories
PublikacjaThe paper summarizes the results of a numerical investigation designed to study the soil-structure interaction effects on modal parameters of three office buildings. The reinforced-concrete 4-storey, 8-storey, and 12-storey office buildings, each with additional two levels of embedded basements, represent low, medium, and high-rise structures, respectively. In order to conduct this research, detailed finite-element structure models...
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Experimental study on steel columns subjected to impact load under earthquake conditions
PublikacjaEarthquakes affecting urbanized regions cause exceptional loads to load bearing structural elements such as columns. Such a boost in the load conditions can lead to severe damages which, in a worst case scenario, can lead to a total collapse of a building. This boost is caused by the horizontal ground movement generating a rise in the internal forces due to considerable large displacement between the top and bottom support of columns....
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Retention behaviour of some high-intensity sweeteners on different SPE sorbents
PublikacjaThe objective of this paper is to provide information about application of solid phase extraction (SPE) for isolation of nine high-intensity sweeteners (acesulfame-K, alitame, aspartame, cyclamate, dulcin, neotame, saccharin, sucralose and neohesperidin dihydrochalcone) from aqueous solutions. The influence of several types of LC-MS compatible buffers (different pH values and compositions) on their recovery has been studied and...
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The elasto-plastic numerical study of crack initiation in notched PMMA specimens under uniaxial loading conditions – Tension and torsion
PublikacjaThis paper presents the results of FEM numerical calculations aimed at describing the plastic strain and stress fields under critical loading conditions: tensile force or torsional moment. The calculations were carried out with reference to the results of experimental tensile and torsional tests of flat PMMA specimens weakened with V-notches of different root radii: 0.5, 2 and 10 mm. The procedure for conducting nonlinear numerical...
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Effectiveness of pollutants removal in hybrid constructed wetlands – different configurations case study
PublikacjaIn recent years, an increase in interest in hybrid constructed wetland systems (HCWs) has been observed. The aim of the paper is to compare different HCW configurations in terms of mass removal rates and efficiency of pollutants removal. Analysed data have been collected at multistage constructed wetlands in Poland, which are composed by at least two beds: horizontal subsurface flow (SSHF) and vertical subsurface flow (SSVF). The...
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Preferences Towards Working in Culturally Diverse Teams at Different Stages of the Entrepreneurial Process
PublikacjaAs entrepreneurial teams become prevalent, it is important to study factors related to their creation and effectiveness. The goal of the current research was to analyze preferences towards working in a multicultural team (MCT) versus a single culture team (SCT) at different stages of the entrepreneurial process. The study involved students originating from various cultures with previous experience in both SCTs and MCTs as participants....
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ISSUE OF MAKING DECISIONS WITH REGARD TO SHIP TRAFFIC SAFETY IN DIFFERENT SITUATIONS AT SEA
PublikacjaThe paper refers to the possibilities of making operational decisions that would enable to ensure safety to a ship in the event of application of the statistical decision theory with consideration of an expected value of consequences as a criterion for making such a decision. General description includes conditions for carrying out transportation tasks by ships and it has been shown that following this description it is possible...
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How digital technology affects working conditions in globally fragmented production chains: Evidence from Europe
PublikacjaThis paper uses a sample of over 9 million workers from 22 European countries to study the intertwined relationship between digital technology, cross-border production links and working conditions. We compare the social consequences of technological change exhibited by three types of innovation: computerisation (software), automation (robots) and artificial intelligence (AI). To fully quantify work-related wellbeing, we propose...
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Protochlorophyllide in model systems — An approach to in vivo conditions
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Effects of stents under asymmetric inflow conditions
PublikacjaW publikacji rozważano komputerowe modele stentów przy niesymetrycznych warunkach napływu i ich wpływ na naprężenia styczne na ściankach. Umożliwia to znajdowanie kształtów stentów, które są mniej wrażliwe na brak symetrii napływu. Zmiany kształtów arterii można wiązać ze zmianami charakterystyki przepływów takimi jak m.in. naprężenia styczne na ściankach, które zwiększają ryzyko restenozy. Posłużono się również pojęciem dyssypacji...
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Complexity of weak acceptonic conditions in tree automata
PublikacjaRozważano złożoność problemu pustości dla automatów na drzewach ze słabymi warunkami akceptowalności. Rozważano także translacje pomiędzy słabymi i silnymi warunkami akceptowalności.
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Existence of solutions of differential equations with boundary conditions
PublikacjaPraca dotyczy równań różniczkowych z liniowym warunkiem brzegowym zależnym od parametru. Podane zostały warunki dostateczne na istnienie rozwiązania powyższego zagadnienia. Przy dowodzie i konstrukcji iteracji monotonicznych zastosowano metodę górnych i dolnych rozwiązań. O prawej stronie zagadnienia zakładano jednostronny warunek Lipschitza.
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Influence of the annealing conditions on the resistivity of Nd2CuO4 singlecrystals
PublikacjaW pracy wyznaczono temperaturową zależność oporności w płaszczyźnie ab dla dwóch grup kryształów Nd2CuO4 w zakresie 50-300 K.
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On delay differential equations with nonlinear boundary conditions
PublikacjaStosując metodę iteracji monotonicznych podano warunki dostateczne na istnienie kwazirozwiązań lub ekstremalnych rozwiązań rozpatrywanego zagadnienia. Problem jednoznaczności rozwiązania był również przedmiotem badań. Zajmowano się również nierównościami różniczkowymi z opóżnionymi argumentami.
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Advanced differential equations with nonlinear boundary conditions.
PublikacjaBadano problemy istnienia rozwiązań dla równań różniczkowych z nielinowymi warunkami brzegowymi. Podano też warunki dostateczne na istnienie rozwiązań ekstremalnych. Przedmiotem badań były również nierówności różniczkowe z wyprzedzonym argumentem.
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Ordinar differential equations with nonlinear boundary conditions
PublikacjaPraca dotyczy zwyczajnych równań różniczkowych z nieliniowymi warunkami brzegowymi. Sformułowano warunki dostateczne na istnienie rozwiązania (jedynego lub ekstremalnych) zakładając pewną regularność na prawe strony równania i warunek brzegowy. Warunki brzegowe typu okresowego lub antyokresowego są szczególnymi przypadkami ogólnego warunku dyskutowanego w tej pracy.
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Influence of traffic conditions on the operating fuel consumption
PublikacjaPrzedstawiona w pracy metoda umożliwia ocenę warunków eksploatacji pojazdu. Warunki te mogą wynikać zarówno z lokalnej specyfiki ruchu pojazdów jak również ze sposobu prowadzenia auta przez kierowcę. W pracy zamieszczono przykłady oceny zarejestrowanych w normalnej eksploatacji warunków ruchu pojazdu i ich wpływu na przebiegowe zużycie paliwa.
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Control conditions for geocomputing within general hypoplasticity
PublikacjaPrzedstawiono w artykule analizę oryginalności i stabilności problemu warunków brzegowych (BVP). Zaprezentowano niektóre warunki numeryczne, dzięki którym można uzyskać oryginalne i stabilne rozwiązania w zakresie hypoplastyczności. Przeanalizowano wiele teoretycznych aspektów, które pojawiają się wskutek zmiany typu równań różniczkowych. Wyprowadzono kryteria dla przypadku liniowego, dobrze postawionego problemu i dla stabilności...
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A model of risk for assessment of ships in damaged conditions
PublikacjaW pracy omówiono problemy związane z modelowaniem zagrożeń, konsekwencji i ryzyka, w metodzie oceny bezpieczeństwa statków w stanie uszkodzonym. W celu dokonania oceny bezpieczeństwa statku, w metodzie zastosowano podejścia oparte na ocenie zachowania się statku i ocenie ryzyka. Podejście oparte na ocenie zachowania się statku związane jest z oceną charakterystyk hydromechanicznych statku w stanie uszkodzonych w warunkach zbliżonych...
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INFLUENCE OF MEASURING CONDITIONS ON TYRE/ROAD NOISE
PublikacjaA decisive factor for the development of tyres and road surfaces is the ability to conduct representative and reproducible measurements of selected characteristics related to the interaction of tyres and road surfaces. In terms of tyre/road noise measurements in Europe two methods described in ISO/FDIS 11819-2 and ECE Regulation No.117 are used. The latter is compulsory for assigning the tyre noise labels. The methodologies differ...
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Assessment of Road Restraint Systems in Polish Conditions
PublikacjaKey to understanding the needs and tools of road infrastructure management is identifying the hazards and their sources involved in having no or faulty road restraint systems. Clarity is also needed on why the systems are wrongly designed, constructed, built and operated. To ensure that the problem is adequately understood, research and site observations were conducted and...
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Improving the quality of speech in the conditions of noise and interference
PublikacjaThe aim of the work is to present a method of intelligent modification of the speech signal with speech features expressed in noise, based on the Lombard effect. The recordings utilized sets of words and sentences as well as disturbing signals, i.e., pink noise and the so-called babble speech. Noise signal, calibrated to various levels at the speaker's ears, was played over two loudspeakers located 2 m away from the speaker. In...
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Conditions and capacity for implementing Poland’s vision zero
PublikacjaSince 1991 Poland has been systematically reducing its traffic hazard. Despite considerable progress Poland is still among the most dangerous countries in the European Union. The key types of actions that help to reduce fatalities include enhancement of pedestrian safety, reducing the number of speeding drivers and eliminating or reducing hazard on the road. The paper presents a brief diagnosis of the state of road safety in Poland...
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Exact resultant equilibrium conditions for intersecting shells
PublikacjaWyprowadzono ścisłe, globalne i lokalne warunki równowagi dla dwóch przecinających się powłok. Wspólna powierzchnia podstawowa powłoki składa się z czterech regularnych powierzchni materialnych, sztywno połączonych wzdłuż powierzchniowej krzywej osobliwej modelującej połączenie. Localne warunki równowagi otrzymano poprzez ścisłe całkowanie po grubości powłoki globalnych warunków równowagi mechaniki ośrodka ciągłego.
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Reception of GNSS Signals Under Jamming Conditions
PublikacjaThe article focuses on performance of Global Navigation Satellite System receivers in environment where intentional interference is present. First part is a general description of GNSS systems. Secondly, types of positioning service disturbances are specified. In the third part authors present a scheme of measurement stand which is used to evaluate the influence of interference on reception of navigation signals. Next, research...
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CONDITIONS OF THE GREEN TRANSFORMATION. THE CASE OF THE EUROPEAN UNION
PublikacjaThe main purpose of the paper is to identify the factors that determine the course of green transformation and to assess the current stage and possible directions of change in subsequent years in EU countries. The literature lacks comprehensive studies that show the impact of diverse types of factors on the course of green transformation. For this purpose, two perspectives of the research – economic and environmental – are usually...
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Evaluation of fire hazard in electrical installations due to unfavorable ambient thermal conditions
PublikacjaEvaluation of fire hazard caused by electrical installations is a difficult and important topic, and it limits the possibility of loss of life or health of people, as well as the occurrence of significant property damage. In particular, this hazard was caused by power cables and especially photovoltaic (PV) installations. The authors proved that power cables directly exposed to strong solar radiation are likely to exceed maximum...
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Thermal performance of a prototype plate heat exchanger with minichannels under boiling conditions
PublikacjaTo solve the problem and to meet the requirements of customers in the field of high heat fluxes transfer in compact units, a new design of plate heat exchanger with minichannels (minichannels PHE) was proposed. The aim was to construct a compact heat exchanger of high effectiveness for the purpose of household cogeneration ORC system. In this paper the experimental analysis of an assembled prototype of such compact heat exchanger...
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Robustness of contact-less optical method, used for measuring contact wire position in changeable lighting conditions
PublikacjaThe article presents verification of robustness of contactless method based on 2D image camera, which is used to measure catenary contact wire position in changeable ambient lighting conditions. Robustness in changeable lighting conditions is ensured through the combination of advanced image processing for background information removal and the algorithm of error correction. This algorithm detects incorrect images and substitutes...
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Seismic gap between buildings founded on different soil types experiencing pounding during earthquakes
PublikacjaSeveral formulas have been suggested in the literature to evaluate the minimum seismic gap that would prevent collisions between adjacent buildings during earthquakes, including those based on the absolute sum of the peak displacements (ABS), square root of the sum of the squares (SRSS), the double difference method (DDC), Australian code, and approach proposed by Naderpour et al. The aim of the present study is to evaluate the...
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THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THIN-WALLED BEARING SHELL’S DESIGN PARAMETERS AND ASSEMBLY CONDITIONS ON THE HOLDING TORQUE INSIDE A HOUSING BORE OF A CONNECTING ROD
PublikacjaThe aim of the work was the experimental and theoretical evaluation of the influence of the most important parameters determining the holding torque of a thin-walled bearing shell inside a housing bore of a connecting rod. The main investigated parameters were defned by authors experience in this feld. In the frst stage of research, a special test stand was designed in order to allow measuring the real values of the friction torque...
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Numerical analysis of the container vessel's self-propulsion at different rudder deflection angles
PublikacjaNowadays, CFD becomes one of the most commonly used research method in ship hydrodynamics, limited to the analyses of hull resistance in calm water. With continuously improving computing power and increasingly more accurate numerical methods it is possible to simulate more complex cases. State of the art CFD tools also enable development of new ways of assessing ship maneuvering performance. This paper presents an attempt on using...
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Numerical analysis of the container vessel's self-propulsion at different rudder deflection angles
PublikacjaNowadays, CFD becomes one of the most commonly used research method in ship hydrodynamics, limited to the analyses of hull resistance in calm water. With continuously improving computing power and increasingly more accurate numerical methods it is possible to simulate more complex cases. State of the art CFD tools also enable development of new ways of assessing ship maneuvering performance. This paper presents an attempt on...
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Positive solutions to second-order differential equations with dependence on the first-order derivative and nonlocal boundary conditions
PublikacjaIn this paper, we consider the existence of positive solutions for second-order differential equations with deviating arguments and nonlocal boundary conditions. By the fixed point theorem due to Avery and Peterson, we provide sufficient conditions under which such boundary value problems have at least three positive solutions. We discuss our problem both for delayed and advanced arguments α and also in the case when α(t)=t, t∈[0,1]....
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Monotone iterative method to second order differential equations with deviating arguments involving Stieltjes integral boundary conditions
PublikacjaWe use a monotone iterative method for second order differential equations with deviating arguments and boundary conditions involving Stieltjes integrals. We establish sufficient conditions which guarantee that such problems have extremal solutions in the corresponding region bounded by lower and upper solutions. We also discuss the situation when problems have coupled quasi-solutions. We illustrate our results by three examples.
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Absorption and fluorescence spectra of 1,8-diazafluoren-9-one (DFO) in PVA polymer for different concentrations
Dane BadawczeAbsorption and fluorescence spectra of 1,8-diazafluoren-9-one (DFO) in PVA film for different concentrations of dye.