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Validation Process for Computational Model of Full-Scale Segment for Design of Composite Footbridge
PublikacjaExperimental tests and numerical simulations of a full-scale segment of a foot and cycle bridge made of polymer composites are presented in the paper. The analysed structure is made of sandwich panels, which consist of glass fibre reinforced polymer (GFRP) multi-layered laminate faces and a PET foam (obtained from recycling) core. The dimensions of the segment cross-section are the same as for the target footbridge; however, span...
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Concrete-filled FRP tubular members in marine and bridge structures
PublikacjaConcrete core of the concrete-filled tubes (CFTs) with circular cross-section is in the case of an axial compression subjected to a spatial state of compressive stresses. This state leads to enhancement in the concrete strength. The enhancement is utilized in Eurocode 4 design procedures for CFSTs (i.e. CFTs with tube made of steel). The structural design of CFFTs (i.e. CFTs with tube made of Fibre Reinforced Polymer - FRP) is...
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Experimental and numerical investigations of ultimate strength of imperfect stiffened plates of different slenderness
PublikacjaThe objective of this study is to analyse the behaviour of compressed stiffened plates of different slenderness using experimental and numerical methods. The presented results are part of a long-term project to investigate the ultimate strength of geometrically imperfect structures subjected to different degradation phenomena, including corrosion degradation and locked cracks. Several specimens were subjected to a uniaxial compressive...
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Smoothed transition curve for railways
PublikacjaThe work draws attention to the existing situation in the area of transition curves used in the geometric layouts of the railway track. Difficulties in the practical implementation and maintenance of very small horizontal ordinates of the transition curve and the ordinates of the gradient due to cant in the initial section, appearing on smooth transition curves, were indicated. The main reason for this situation was the excessive...
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Orthogonality relations for the associated Legendre functions of imaginary order
PublikacjaOrthogonality relations for the associated Legendre functions of imaginary order are derived. They are expressed in terms of the Dirac delta function. The method is based on some known properties of the associated Legendre functions and the Dirac delta distribution. A special case of one of the relations has appeared in some recent applications.
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A Dirac delta-type orthogonality relation for the on-the-cut generalized associated Legendre functions of the first kind with imaginary second upper indices
PublikacjaThe orthogonality relation for the on-the-cut generalized associated Legendre functions of the first kind with imaginary second upper indices is evaluated in a closed form. It is found to be proportional to a sum of two terms, both depending on the second upper indices and containing the Dirac delta distribution.
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On the derivatives $\partial^{2}P_{\nu}(z)/\partial\nu^{2}$ and $\partial Q_{\nu}(z)/\partial\nu$ of the Legendre functions with respect to their degrees
PublikacjaWe provide closed-form expressions for the degree-derivatives $[\partial^{2}P_{\nu}(z)/\partial\nu^{2}]_{\nu=n}$ and $[\partial Q_{\nu}(z)/\partial\nu]_{\nu=n}$, with $z\in\mathbb{C}$ and $n\in\mathbb{N}_{0}$, where $P_{\nu}(z)$ and $Q_{\nu}(z)$ are the Legendre functions of the first and the second kind, respectively. For $[\partial^{2}P_{\nu}(z)/\partial\nu^{2}]_{\nu=n}$, we find that % \begin{displaymath} \frac{\partial^{2}P_{\nu}(z)}{\partial\nu^{2}}\bigg|_{\nu=n} =-2P_{n}(z)\Li_{2}\frac{1-z}{2}+B_{n}(z)\ln\frac{z+1}{2}+C_{n}(z), \end{displaymath} % where...
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Some integrals and series involving the Gegenbauer polynomials and the Legendre functions on the cut (-1,1)
PublikacjaZaprezentowano metode obliczenia dwóch całek oznaczonych zawierających wielomiany Gegenbauera. Wynik wykorzystano do znalezienia sum czterech szeregów o wyrazach zawierających wielomiany Gegenbauera oraz funkcje Legendre'a (pierwszego lub drugiego rodzaju) na odcinku (-1,1).
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Existence and approximate solutions of Neumann problems
PublikacjaDyskutowany jest problem Neumanna dla równań różniczkowych drugiego rzędu.Praca dotyczy istnienia rozwiązań i zbieżnosci iteracji monotonicznych któresą przybliżonymi rozwiązaniami omawianych zagadnień. Określone zostały wa-runki zbieżności takich ciągów oraz określono rodzaj tej zbieżnosci.
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An orthogonality relation for the Whittaker functions of the second kind of imaginary order
PublikacjaPrzeprowadzono dowód ortogonalności funkcji Whittakera drugiego rodzaju rzędu urojonego. Użyto metody analogicznej do tej, którą zaprezentowano we wcześniejszej pracy tych samych autorów [J. Math. Anal. Appl. 365 (2010) 195-197], poświęconej funkcjom Macdonalda rzędu urojonego.
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Laplace domain BEM for anisotropic transient elastodynamics
PublikacjaIn this paper, we describe Laplace domain boundary element method (BEM) for transient dynamic problems of three-dimensional finite homogeneous anisotropic linearly elastic solids. The employed boundary integral equations for displacements are regularized using the static traction fundamental solution. Modified integral expressions for the dynamic parts of anisotropic fundamental solutions and their first derivatives are obtained....
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Parametric method applicable in assessing breakout force and time for lifting slender bodies from seabed
PublikacjaThe article presents a parametric method applicable in assessing the suction force of a slender body to the seabed, and prognosing the body extrication time. Along with the body weight in water, the information on the suction force is essential for assessing the force needed to lift the object from the seabed. Based on the Foda theory and the resulting integral equation, which relates the maximum suction force with basic parameters...
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Remarks on the Subject of Back-Up Protection of Residual Current Devices
PublikacjaResidual current devices without integral overcurrent protection (RCCBs) are back-up protected by fuses or miniature circuit-breakers (MCBs). If the latter are used, special attention must be given to the coordination between an RCCB and an MCB. This paper indicates probable cases of the aforementioned devices coordination, in which back-up protection of the RCCB is not adequate. A laboratory test has shown that depending on the...
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Weighted 2-sections and hypergraph reconstruction
PublikacjaIn the paper we introduce the notion of weighted 2-sections of hypergraphs with integer weights and study the following hypergraph reconstruction problems: (1) Given a weighted graph , is there a hypergraph H such that is its weighted 2-section? (2) Given a weighted 2-section , find a hypergraph H such that is its weighted 2-section. We show that (1) is NP-hard even if G is a complete graph or integer weights w does not exceed...
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New transition curve adapted to railway operational requirements
PublikacjaThe paper points to the limited possibilities of improving the existing situation in the area of transition curves used in geometrical layouts of the railway track. Difficulties in the practical implementation and maintenance of very small horizontal ordinates of the transition curve and the ordinates of the gradient due to cant in the initial section, appearing on smooth transition curves, were indicated. The main reason for this...
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Thin-walled frames and grids - statics and dynamics
PublikacjaFrames and grids assembled with thin-walled beams of open cross-section are widely applied in various civil engineering and vehicle or machine structures. Static and dynamic analysis of theses structures may be carried out by means of different models, startingfrom the classical models made of beam elements undergoing the Kirchhoff assumptions to the FE discretization of whole frame into plane elements. The former model is very...
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Static load test on concrete pile – instrumentation and results interpretation
PublikacjaFor some time (since 8-10 years in Poland) a special static load tests on instrumented piles are carried out. Such studies are usually of a scientific nature and provide detailed quantitative data on the load transfer into the ground and characteristics of particular soil layers interaction with a pile shaft and pile base. Deep knowledge about the pile-subsoil interaction can be applied for a various design purposes, e.g. numerical...
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Multi-stage magnetic-fluid seals for operating in water - life test procedure, test stand and research results
PublikacjaThe edge criteria for magnetic-fluid seals durability research are critical for the seal'stechnological usefulness. The magnetic fluid seal technology in water is much moredifficult technological problem in comparison to gas or vacuum environment. There isalways problem with immediate contact between magnetic fluid and the environmentaluninspected liquids. In the paper are presented ways of experiments definitions carried outwith...
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Static Load Test on Instrumented Pile – Field Data and Numerical Simulations
PublikacjaFor some time (since 8-10 years in Poland) a special static load tests on instrumented piles are carried out. Such studies are usually of a scientific nature and provide detailed quantitative data on the load transfer into the ground and characteristics of particular soil layers interaction with a pile shaft and pile base. Deep knowledge about the pile-subsoil interaction can be applied for a various design purposes, e.g. numerical...
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Application of polymer element in reduction of temporary steel grandstand vibrations
PublikacjaThe numerical analysis focused on reduction of vibrations of a temporary steel scaffolding grandstand has been conducted in this paper. These types of structures are regularly subjected to dynamic loads which, in conjunction with light and quite slender structural members, may induce dangerous vibrations. To increase their safety, temporary steel grandstands are usually strengthened with the diagonal stiffeners of tubular cross...
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Experimental study on the effectiveness of polymer damper in damage reduction of temporary steel grandstand
PublikacjaA large number of accidents, involving collapses of temporary grandstands during different types of events, were observed in the past. If the synchronized movement of people is tuned with the natural frequency of the affected part of the structure, resonance might occur. It may lead to severe damages of grandstands, their collapse or panic among the spectators. The aim of the paper is to assess, through preliminary experimental...
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The In-Depth Studies of Pulsed UV Laser-Modified TiO2 Nanotubes: The Influence of Geometry, Crystallinity, and Processing Parameters
PublikacjaThe laser processing of the titania nanotubes has been investigated in terms of morphology, structure, and optical properties of the obtained material. The length of the nanotubes and crystallinity, as well as the atmosphere of the laser treatment, were taken into account. The degree of changes of the initial geometry of nanotubes were checked by means of scanning electron microscopy, which visualizes both the surface and the cross-section....
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Assessment of the Influence of Road Infrastructure Parameters on the Behaviour of Drivers and Pedestrians in Pedestrian Crossing Areas
PublikacjaPedestrians are participants and, most likely, fatalities in every third road traffic accident in Poland. Over 30% of all fatalities on Polish roads are pedestrians. Accidents with pedestrians are very often the result of various factors related to the infrastructure and behaviour of pedestrians and drivers. The objective of the work was to assess driver and pedestrian behaviour in pedestrian crossing areas. The research also served...
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IoT protocols, architectures, and applications
PublikacjaThe proliferation of embedded systems, wireless technologies, and Internet protocols have enabled the IoT to bridge the gap between the virtual and physical world enabling the monitoring and control of the environment by data processing systems. IoT refers to the inter-networking of everyday objects that are equipped with sensing, computation, and communication capabilities. These networks can collaboratively interact and perform...
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Pedestrian Safety at Midblock Crossings on Dual Carriageway Roads in Polish Cities
PublikacjaRoad crossings across two or more lanes in one direction are particularly dangerous due to limited sight distance and high vehicle speeds. To improve their safety, road authorities should provide safety treatments. These may include additional measures to reduce speed and narrow the road cross-section and the introduction of active pedestrian crossings. Equipped with flashing lights activated automatically when a pedestrian is...
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Energy storage device based on flywheel, power converters and Simulink real-time
PublikacjaThis electronic document is a “live” template and already defines the components of your paper [title, text, heads, etc.] in its style sheet. Paper presents information on Energy Storage Device based on Flywheel and bi-directional IGBT Power Converters – designed for LINTE^2 laboratory owned by Gdansk University of Technology in Poland. Paper is divided into four sections. First section of the paper provides introductory information...
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A Generalized Version of the Lions-Type Lemma
PublikacjaIn this short paper, I recall the history of dealing with the lack of compactness of a sequence in the case of an unbounded domain and prove the vanishing Lions-type result for a sequence of Lebesgue-measurable functions. This lemma generalizes some results for a class of Orlicz–Sobolev spaces. What matters here is the behavior of the integral, not the space
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Evaluation of Street Lighting Efficiency Using a Mobile Measurement System
PublikacjaThe issue concerns the initial stage of work on a method for performing a rapid assessment of the energy efficiency and illuminance of a street lighting installation. The proposed method is based on simultaneous measurement of illuminance from three lux meters placed on the roof of the vehicle. The data are acquired in road traffic, while the vehicle is driving. The proposed solution will allow in the future to quickly and reproducibly...
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A study of the kinetics of bismuth telluride synthesis by an oxide reduction method
PublikacjaThe kinetics of a reduction of bismuth and tellurium oxides in a hydrogen atmosphere, leading to the formation of thermoelectric bismuth telluride is investigated. The evaluation of the reaction kinetics was based on a thermogravimetric analysis performed in non-isothermal conditions. A non-parametric analysis method and the Friedman method were used for the evaluation of the data. Additionally, for a better understanding of the...
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A methodology for ultimate strength assessment of ship hull girder accounting for enhanced corrosion degradation modelling
PublikacjaThe presented work shows a methodology for the ultimate strength assessment of a ship hull, considering enhanced corrosion modelling. The approach is based on the classical Smith method. However, the recent findings regarding the impact of corrosion degradation on ultimate strength are incorporated. To this end, the stress–strain relationships for particular elements composing ship hull cross-section are modified using a specially...
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A simplified method to assess the impact of ship-to-ship collision on the risk of tanker ship hull girder breaking accounting for the effect of ageing
PublikacjaOne of the most critical structural failures is the exceedance of the ship hull girder’s ultimate strength, which may result in hull breaking, and subsequent severe consequences, including loss of life and property as well as environmental damage in case of an oil spill. A cause for such loss of structural continuity can be triggered by a collision with another vessel. In addition, the ageing mechanisms of the hull structure could...
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Wear Resistance Enhancement of Al6061 Alloy Surface Layer by Laser Dispersed Carbide Powders
PublikacjaIn this paper, results of the experimental study on improving wear resistance in sliding friction of Al-based alloy are presented. The technique used involves the formation of a metal matrix composite (MMC) in the alloy surface layer by laser dispersion of carbide powders such as WC, TiC and SiC. For WC and TiC MMC surface coatings fabricated under conditions typical for most of the technologically relevant solid-state lasers (wavelength...
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Diagnostics and monitoring of the longest span extradosed bridge in Europe
PublikacjaThe article presents complex diagnostic procedures applied for the purpose of behavior analysis of the extradosed bridge with the longest span in Europe that was built in 2018 in Poland. The system of health monitoring was used to: register internal forces in temporary supports, monitor concrete bonding, perform in situ diagnostics and operation tests. The bridge is a continuous four-span structure with spans theoretical lengths...
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Thermal buckling of functionally graded piezomagnetic micro- and nanobeams presenting the flexomagnetic effect
PublikacjaGalerkin weighted residual method (GWRM) is applied and implemented to address the axial stability and bifurcation point of a functionally graded piezomagnetic structure containing flexomagneticity in a thermal environment. The continuum specimen involves an exponential mass distributed in a heterogeneous media with a constant square cross section. The physical neutral plane is investigated to postulate functionally graded material...
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A Diagnostic Method Based on Deflection Analysis for Monitoring Post-elastic Response of Beams
PublikacjaA non-destructive diagnostic method based on deflection analysis for monitoring the post-elastic response of beams was developed, and a diagnostic indicator was proposed. The indicator was defined as the second moment of the normalised curvature function about the mid-span, where the curvature was computed from the normalised deflection function. Elastic reference values of the indicator were computed for simply supported beams...
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Four-Port Circulator Using Reduced Ground Plane Ferrite Coupled Line Junction
PublikacjaIn this paper the investigations of four-port circula-tor using longitudinally magnetized ferrite coupled line section are presented. The device is designed by cascading ferrite section with magic-T junction ensuring its even and odd mode excitation. The scattering parameters of ferrite coupled line junction are calculated using own software and verified with the use of commercial software. The even and odd excitation of ferrite...
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IoT for healthcare applications
PublikacjaThis chapter summarizes IRACON contributions related to the application of IoT in healthcare. It consists of the following three sections. Section 8.1 presents the measurement campaigns and the related statistical analysis to obtain various channel models for wearable and implantable devices. In addition, the importance of physical human-body phantoms used for channel, Specific Absorption Rate (SAR), and Electromagnetic (EM) exposure...
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Road Safety Observatories within the Structure of Integrated Transport Safety Systems
PublikacjaAccurate knowledge about the causes, circumstances and place of transport accidents is the prerequisite to take the correct action to improve transport safety. Developing appropriate organizational structures, forms and methods of management and implementation of safety measures in the sectoral approach condition the success. Therefore the Safety Information System is one of the integral areas of the Integrated Transport Safety...
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The role of observatories in the integrated transport safety systems
PublikacjaAccurate knowledge about the causes, circumstances and place of transport accidents is the prerequisite to take the correct action to improve transport safety. Developing appropriate organizational structures, forms and methods of management and implementation of safety measures in the sectoral approach condition the success. Therefore, the Safety Information System is one of the integral areas of the Integrated Transport Safety...
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Positive solutions to advanced fractional differential equations with nonlocal boundary conditions
PublikacjaWe study the existence of positive solutions for a class of higher order fractional differential equations with advanced arguments and boundary value problems involving Stieltjes integral conditions. The fixed point theorem due to Avery-Peterson is used to obtain sufficient conditions for the existence of multiple positive solutions. Certain of our results improve on recent work in the literature.
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Cognitum Ontorion: Knowledge Representation and Reasoning System
PublikacjaAt any point of human activity, knowledge and expertise are a key factors in understanding and solving any given problem. In present days, computer systems have the ability to support their users in an efficient and reliable way in gathering and processing knowledge. In this chapter we show how to use Cognitum Ontorion system in this areas. In first section, we identify emerging issues focused on how to represent and inference...
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Moisture content during and after high- and normal-temperature drying processes of wood
PublikacjaThe aim of the article is to present the results of moisture content of wood during and after the high-temperature steam and air–steam mixture drying processes and after an open air-drying process. The knowledge of moisture content changes of wood in the process of its drying is one of the important parameters to economy drying process and to keep the quality of dried wood. Wood samples, namely, spruce (Picea abies K.) and beech...
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Analysis of the relationship between the length of eye fixation and the parameters of advertisements visible from the road
PublikacjaIn Poland, many advertising signs addressed to motorists are located along the roadside. Advertisements do not serve any traffic related purpose and can distract drivers making them less reliable and as a consequence, reduce road safety. The existing regulations only apply to the carriageway. The research is conducted as part of the RID project. The objective of the RID project is to create a "Manual for positioning roadside advertising...
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Accuracy improvement of the prestressed concrete structures precise geometry assessment by use of bubble micro-sampling algorithm
PublikacjaPrestressed concrete structures are well-known technology for a vast period, but nevertheless, this very technology is a leading solution, currently used in construction industry. Prestressed concrete structures have a huge advantage over conventional methods because it uses the properties of concrete in a very efficient way. The main idea behind this technology is to introduce into the cross-section of the structure, the internal...
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Rapid Simulation-Driven Multiobjective Design Optimization of Decomposable Compact Microwave Passives
PublikacjaIn this paper, a methodology for fast multiobjective optimization of the miniaturized microwave passives has been presented. Our approach is applicable to circuits that can be decomposed into individual cells [e.g., compact microstrip resonant cells (CMRCs)]. The structures are individually modeled using their corresponding equivalent circuits and aligned with their accurate, EM simulated...
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Influence of Nitriding and Laser Remelting on Properties of Austenitic Stainless Steel Type X10CrNi18-8 and Cavitation Erosion Resistance
PublikacjaThe paper presents properties of surface layers. Surface layers were obtained by using low temperature glow–discharge nitriding process and laser remelting carried out on austenitic stainless steel type X10CrNi18-8. Investigations were done by using an Ultra Nanoindentation Tester (UNHT) in the Warsaw Institute of Fundamental Technological Research. The influence of the above mentioned...
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Low-Cost Method for Internal Surface Roughness Reduction of Additively Manufactured All-Metal Waveguide Components
PublikacjaIn this study, a novel low-cost polishing method for internal surface roughness reduction of additively manufactured components, developed for waveguide (WG) circuits operating in the millimeter frequency range is proposed. WG components fabricated using powder bed fusion (PBF) generally feature roughness of ten to fifty microns, which influences the increase of roughness-related conductor power losses having a major effect on...
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Magnetically sensitive fiber probe with nitrogen-vacancy center nanodiamonds integrated in a suspended core
PublikacjaEfficient collection of photoluminescence arising from spin dynamics of nitrogen vacancy (NV) centers in diamond is important for practical applications involving precise magnetic field or temperature mapping. These goals may be realized by the integration of nanodiamond particles with optical fibers and volumetric doping of the particles alongside the fiber core. That approach combines the advantages of robust axial fixation of...
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Retrievable strain measuring system in screw displacement piles - readings and results interpretation problems
PublikacjaStatic load tests on foundation piles are generally carried out in order to determine load – displacement characteristic of the pile. For more detailed information, e.g. force distribution along the shaft, load transfer mechanism and characteristics of soil-structure interaction (unit resistance curves t-z, q-z) additional pile instrumentation is required. Most popular techniques focus on direct concrete strain measurements and...
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Monotone iterative method for first-order differential equations at resonance
PublikacjaThis paper concerns the application of the monotone iterative technique for first-order differential equations involving Stieltjes integrals conditions. We discuss such problems at resonance when the measure in the Stieltjes integral is positive and also when this measure changes the sign. Sufficient conditions which guarantee the existence of extremal, unique and quasi-solutions are given. Three examples illustrate the results.