Search results for: pahs
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Comparison of centralized and decentralized preemption in MPLS networks
PublicationPreemption is one of the crucial parts of the traffic engineering in MPLS networks. It enables allocation of high-priority paths even if the bandwidth on the preferred route is exhausted. This is achieved by removing previously allocated low-priority traffic, so as enough free bandwidth becomes available. The preemption can be performed either as a centralized or a decentralized process. In this article we discuss the differences...
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Vision-based motion analysis of kitesurfer
PublicationKitesurfing is a relatively recent phenomenon with raising popularity worldwide – a recently developed extreme water sport considered a high-risk injury sport. It combines elements of several other sports, in particular sailing, surfing, windsurfing, wakeboarding, and snowboarding. The main purpose of authors’ research in the present paper is to use a vision system technique for measuring a kitesurfer’s body movements in order...
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Multimedia in teaching economics and management in higher education.
PublicationNowadays, the use of multimedia teaching materials at universities makes a standard practice. However their saturation is still quite low comparing to the expectations of students - the main consumers of the information contained therein. This article will present the results of research conducted among students of Management and Engineering Management carried at the Technical University of Gdańsk. Some students of Computer Science...
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The equivariant spectral flow and bifurcation of periodic solutions of Hamiltonian systems
PublicationWe define a spectral flow for paths of selfadjoint Fredholm operators that are equivariant under the orthogonal action of a compact Lie group as an element of the representation ring of the latter. This G-equivariant spectral flow shares all common properties of the integer valued classical spectral flow, and it can be non-trivial even if the classical spectral flow vanishes. Our main theorem uses the G-equivariant spectral flow...
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Modeling nitrous oxide production by a denitrifying-enhancedbiologically phosphorus removing (EBPR) activated sludge in thepresence of different carbon sources and electron acceptors
PublicationIn this study, the IWA Activated Sludge Model No. 2d (ASM2d) was expanded to identify the most important mechanisms leading to the anoxic nitrous oxide (N2O) production in the combined nitrogen (N) and phosphorus (P) removal activated sludge systems. The new model adopted a three-stage denitrification concept and was evaluated against the measured data from one/two-phase batch experiments carried out with activated sludge withdrawn...
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Efficiency of landfill leachate treatment in a MBR/UF system combined with NF, with a special focus on phthalates and bisphenol A removal
PublicationIn this study, a pilot-scale membrane bioreactor (MBR) was operated at a municipal solid waste plant (MSWP) to treat a mixture of landfill leachates (LLs) obtained from modern (MP-LLs) and previous (PP-LLs) waste cells. The MBR unit combined anoxic and aerobic zones with external ultra- and nanofiltration (MBR/UF and MBR/UF/NF, respectively). In addition to the removal of macropollutants, special attention was given to phthalates...
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Load path sensitivity and multiaxial fatigue life prediction of metals under non-proportional loadings
PublicationEngineering components often operate under complex loadings, in which the variable amplitude multiaxial stresses are raised by geometric discontinuities including holes, grooves, fillets and shoulders, etc. Besides, the non-proportional loading will lead to the rotation of maximum principal stress/strain and additional fatigue damage of structural elements in service. Consequently, the multiaxial and non-proportional loading have...
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Hydrophobic deep eutectic solvents as “green” extraction media for polycyclic aromatic hydrocarbons in aqueous samples
PublicationThe paper presents novel nonionic and hydrophobic deep eutectic solvents which were synthesized from natural compounds, i.e., thymol, ±camphor, decanoic and 10-undecylenic acids. Fundamental physicochemical properties of the synthesized deep eutectic solvents were determined, followed by their application as extractants in ultrasound-assisted dispersive liquid-liquid microextraction to isolate and enrich polycyclic aromatic hydrocarbons...
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PHASE OBJECT OBSERVATION SYSTEM BASED ON DIFFRACTION PHASE MICROSCOPY
PublicationIn the paper authors present a special measurement system for observing phase objects. The diffraction phas microscopy makes it possible to measure the dimensions of a tested object with a nanometre resolution. To meet this requirement, it is proposed to apply a spatial transform. The proposed setup can be based either on a two lenses system (called 4 f ) or a Wollaston prism. Both solutions with all construction aspects are described...
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Subharmonic solutions for a class of Lagrangian systems
PublicationWe prove that second order Hamiltonian systems with a potential of class C1, periodic in time and superquadratic at infinity with respect to the space variable have subharmonic solutions. Our intention is to generalise a result on subharmonics for Hamiltonian systems with a potential satisfying the global Ambrosetti-Rabinowitz condition from [P. H. Rabinowitz, Proc. Roy. Soc. Edinburgh Sect. A, 114 (1990), 33-38]. Indeed, we weaken...
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Operational causes of fatigue failures within the passages of gas turbine engines
PublicationThe short profile of a fatigue wear process of gas turbine engine's constructional elements has been introduced in the article. The primary causes of a fatigue cracks formation within the mechanical system as well as within the passages of the engine have been showed. Especial attention was devoted to the low-cycle fatigue, what is associated with unsteady thermal-flow processes being worked out in the passages.The selected damages...
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Parallelization of Compute Intensive Applications into Workflows based on Services in BeesyCluster
PublicationThe paper presents an approach for modeling, optimization and execution of workflow applications based on services that incorporates both service selection and partitioning of input data for parallel processing by parallel workflow paths. A compute-intensive workflow application for parallel integration is presented. An impact of the input data partitioning on the scalability is presented. The paper shows a comparison of the theoretical...
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Influence of laser processing of the low alloy medium carbon structural steel on the development of the fatigue crack
PublicationThe paper contains the results of the structural analysis, hardness tests and fatigue tests conducted for the medium carbon structural steel with low content of Cr and Ni after its processing with CO2 laser beam. Pre-cracks were made in the round compact tension (RCT) specimen used for fatigue test. Next, four paths, parallel to each other, were melted on both sides of the samples using a laser beam. The paths were perpendicular...
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Modelling Long‐Term Transition from Coal‐Reliant to Low‐Emission Power Grid and District Heating Systems in Poland
PublicationEnergy systems require technological changes towards climate neutrality. In Poland, where the power system is dominated by outdated coal-fired power plants, efforts to minimize the environmental impact are associated with high costs. Therefore, optimal paths for the development of the energy sector should be sought in order to achieve ambitious long-term strategic goals, while minimizing the negative impact on the consumers’ home...
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Investigation into MPI All-Reduce Performance in a Distributed Cluster with Consideration of Imbalanced Process Arrival Patterns
PublicationThe paper presents an evaluation of all-reduce collective MPI algorithms for an environment based on a geographically-distributed compute cluster. The testbed was split into two sites: CI TASK in Gdansk University of Technology and ICM in University of Warsaw, located about 300 km from each other, both connected by a fast optical fiber Ethernet-based 100 Gbps network (900 km part of the PIONIER backbone). Each site hosted a set...
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The Mechanism of a Retro-Diels–Alder Fragmentation of Luteolin: Theoretical Studies Supported by Electrospray Ionization Tandem Mass Spectrometry Results
PublicationThe mechanisms of retro-Diels–Alder fragmentation of luteolin are studied theoretically using the Density Functional Theory method (B3LYP hybrid functional) together with the 6-311++G(d,p) basis set and supported by electrospray ionization tandem mass spectrometry (ESI-MS) results. The reaction paths leading to the formation of 1,3A and 1,3B fragment ions observed as the main spectral features in the ESI-MS spectrum are described...
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The Maslov index and the spectral flow—revisited
PublicationWe give an elementary proof of a celebrated theorem of Cappell, Lee and Miller which relates the Maslov index of a pair of paths of Lagrangian subspaces to the spectral flow of an associated path of self-adjoint first-order operators. We particularly pay attention to the continuity of the latter path of operators, where we consider the gap-metric on the set of all closed operators on a Hilbert space. Finally, we obtain from Cappell,...
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Ferromagnetic nanoparticles imaging by means of Magnetic Force Microscopy
Open Research DataFerromagnetic nanoparticles can be used as building blocks for advanced thin film magnets, and can also be used in data storage and biomedical technologies. Nano-crystalline ferrites with the chemical formula NixZn (1 - x) Fe2O4, where x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 show anti-corrosion properties and suppress electromagnetic interference, in the case...
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Badania stateczności i nośności prętów złożonych z podporami sprężystymi
PublicationNiniejsza praca poświecona jest analizom numerycznym i badaniom doświadczalnym ściskanych prętów złożonych, które są często stosowane jako pasy górne kratownic dachowych. Istotny wpływ na nośność tego typu elementów, przy założeniu wyboczenia z płaszczyzny układu, ma odpowiedni dobór przewiązek zapewniający współpracę poszczególnych gałęzi. W pracy przedstawiono rezultaty liniowych analiz stateczności oraz fizycznie i geometrycznie...
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Improving all-reduce collective operations for imbalanced process arrival patterns
PublicationTwo new algorithms for the all-reduce operation optimized for imbalanced process arrival patterns (PAPs) are presented: (1) sorted linear tree, (2) pre-reduced ring as well as a new way of online PAP detection, including process arrival time estimations, and their distribution between cooperating processes was introduced. The idea, pseudo-code, implementation details, benchmark for performance evaluation and a real case example...
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Support Vector Machine Applied to Road Traffic Event Classification
PublicationThe aim of this paper is to present results of road traffic event signal recognition. First, several types of systems for road traffic monitoring, including Intelligent Transport System (ITS) are shortly described. Then, assumptions of creating a database of vehicle signals recorded in different weather and road conditions are outlined. Registered signals were edited as single vehicle pass by. Using the Matlab-based application...
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Some variations of perfect graphs
PublicationWe consider (ψk−γk−1)-perfect graphs, i.e., graphs G for which ψk(H) =γk−1(H) for any induced subgraph H of G, where ψk and γk−1 are the k -path vertex cover number and the distance (k−1)-domination number, respectively. We study (ψk−γk−1)-perfect paths, cycles and complete graphs for k≥2. Moreover, we provide a complete characterisation of (ψ2−γ1)-perfect graphs describing the set of its forbidden induced subgraphs and providing...
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Using Alpha-beta filtration for robustness improvement of a quadrocopter positioning system
PublicationQuadrocopter is an unmanned aerial vehicle (UAV) platform. The position of the robot is determined based on readings from an accelerometer and a gyroscope, but the measurement signals contain broadband noise. This article describes a solution for filtering out the noise based on an Alpha – beta filter. It also presents the methodology of designing and implementing such a filter for noise cancellation in measurement signals from...
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Impact of Initial Population on Evolutionary Path Planning Algorithm
PublicationIn this paper an impact of initial population on evolutionary path planning algorithm is presented. Tested algorithm is used to determine close to optimal ship paths in collision avoidance situation. For this purpose a path planning problem is defined. A specific structure of the individual path and fitness function is presented. For the simulation purposes a close to real tested environment is created. Four tests are performed....
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Large thermo-elastic displacement and stability FEM analysis of multilayered plates and shells
PublicationThe paper concerns the load capacity analysis of thermally loaded multilayered plates and shells. The multilayered body is treated as an equivalent single layer whose kinematics is consistent with first order shear deformation theory. The authors focus on the thermo-elastic stability problem of the thin-walled structures. The equilibrium paths are traced with the use of Riks-Wempner-Ramm algorithm. By making use of the Tsai-Wu...
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Quasilinear elliptic problem in anisotropic Orlicz–Sobolev space on unbounded domain
PublicationWe study a quasilinear elliptic problem $-\text{div} (\nabla \Phi(\nabla u))+V(x)N'(u)=f(u)$ with anisotropic convex function $\Phi$ on the whole $\R^n$. To prove existence of a nontrivial weak solution we use the mountain pass theorem for a functional defined on anisotropic Orlicz-Sobolev space $\WLPhispace(\R^n)$. As the domain is unbounded we need to use Lions type lemma formulated for Young functions. Our assumptions broaden...
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Detection of debonding in reinforced concrete beams using ultrasonic transmission tomography and hybrid ray tracing technique
PublicationThis paper concerns inspection of reinforced concrete elements, with particular emphasis on assessing the quality of the adhesive connection between steel and concrete. A novel theoretical model was developed to determine the paths of transmitted, refracted and reflected elastic waves as well as a creeping wave propagated along the inclusion surface. Imaging the internal structure of tested beams was based on wave propagation measurements...
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A note on polynomial algorithm for cost coloring of bipartite graphs with Δ ≤ 4
PublicationIn the note we consider vertex coloring of a graph in which each color has an associated cost which is incurred each time the color is assigned to a vertex. The cost of coloring is the sum of costs incurred at each vertex. We show that the minimum cost coloring problem for n-vertex bipartite graph of degree ∆≤4 can be solved in O(n^2) time. This extends Jansen’s result [K.Jansen,The optimum cost chromatic partition problem, in:...
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Proton transfer reactions for ionized water clusters
PublicationCalculations of formation energies of the ionized water clusters and energies of reactions between small (including less than eight water molecules) neutral and positively ionized water clusters are presented. Moreover, we discuss some reaction paths between neutral and positively charged dimers, trimers and tetramers and proton transfer reactions (PTR) between cyclic clusters and H3O+ ions which can appear in beam experiments...
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Topography studies of screen-printed carbon electrodes (SPCE) with boron-doped diamond foils
Open Research DataThis dataset contains topography examination of SPCE containing boron-doped diamond BDD foils done with scanning electron microscope. Different points mark different electrode spots: A) working electrode, B) reference electrode, C) counter electrode, D) pads.
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The Research and Development Efficiency of Institutesof the Polish Academy of Sciences and the External Factors Affecting It
PublicationObjective: The aim of the research is to assess the research and development efficiency of the institutes of the Polish Academy of Sciences (PAS) in 2019 and to identify external factors that have a significant impact on it.Research Design & Methods: A two-stage procedure in the field of DEA methodology was used. In the first stage, the efficiency of PAS institutes was estimated using alternative BCC and SBM models....
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Symulacje numeryczne jako wsparcie badania właściwości barier ochronnych
PublicationArtykuł przedstawia możliwości wykorzystania symulacji numerycznych do badań efektywności urządzeń bezpieczeństwa ruchu drogowego w aspekcie sposobów ich konfgurowania. Obecnie w celu dopuszczenia do stosowania bariery ochronne muszą przejść specjalistyczne testy zderzeniowe. Ze względu na wysoki koszt tych badań coraz częściej producenci barier oraz inne podmioty odpowiadające za urządzenia bezpieczeństwa ruchu drogowego (brd)...
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Tourism for older and disabled people
PublicationTourist offer for the older and disabled is getting wider. Many hotels and cities are adjusted to disabled people's needs, but there are not enough safe places for leisure, where they could be surrounded by nature. In comparison with cities - villages and small towns have very little to offer as far as tourism is concerned. This problem is noticed by small local communities that threat it as a chance for their economical development....
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Recycling of Industrial Waste as Soil Binding Additives—Effects on Soil Mechanical and Hydraulic Properties during Its Stabilisation before Road Construction
PublicationTo improve the in situ soil stabilization, different chemical additives are used (ion exchange compounds, additives based on H2SO4 or vinyl polymers, and organic additives using lignosul- fonates). One interesting alternative is the production of additives from various waste materials. The extensive testing of waste-based blends with soil was performed; the mechanical (unconfined compressive strength (UCS)) and hydraulic (capillary...
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The effect of groyne field on trapping macroplastic. Preliminary results from laboratory experiments
PublicationMacroplastic, a precursor of microplastic pollution, has become a new scope of research interest. However, the physical processes of macroplastic transport and deposition in rivers are poorly understood, which makes the decisions of where to locate macroplastic trapping infrastructure difficult. In this research, we conducted a series of experiments in a laboratory channel, exploring the impact of groynes and flexible artificial...
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Yerba Mate - A Long but Current History
PublicationBearing in mind the growing interest in Yerba Mate, a comprehensive study has been prepared containing the most important aspects and possibilities of its use. The introduction of the work contains the species characteristics of Yerba Mate, as well as information about the origin and places of cultivation. The next part focuses on the analysis of the composition, pointing to purine alkaloids, polyphenols, saponins, and minerals...
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Toxicity and chemical analyses of airport runoff waters in Poland
PublicationThe aim of this study was to assess the ecotoxicological effects of various compounds in complex airport effluents using a chemical and ecotoxicological integrated strategy. The present work deals with the determination of sum of PCBs, PAHs, pesticides, cations, anions, phenols, anionic, cationic, non-ionic detergents, formaldehyde and metals – as well as TOC and conductivity – in runoff water samples collected from 2009 to 2011...
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Interpolator wykorzystujący filtr z maskowaniem charakterystyki częstotliwościowej
PublicationInterpolator o dużej krotności wymaga stosowania dolnoprzepustowych filtrów cyfrowych o bardzo wąskim paśmie przejściowym. Przekłada się to na dużą złożoność obliczeniową i problemy z projektowaniem filtrów interpolacyjnych. W pracy zaproponowano użycie metody FRM rozbijającej filtr o wąskim paśmie przejściowym na grupę filtrów o obniżonych wymaganiach, co zmniejsza liczbę niezerowych współczynników. W rezultacie użycie tego rozwiązania...
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Interval incidence graph coloring
PublicationIn this paper we introduce a concept of interval incidence coloring of graphs and survey its general properties including lower and upper bounds on the number of colors. Our main focus is to determine the exact value of the interval incidence coloring number χii for selected classes of graphs, i.e. paths, cycles, stars, wheels, fans, necklaces, complete graphs and complete k-partite graphs. We also study the complexity of the...
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On the Existence of Homoclinic Type Solutions of a Class of Inhomogenous Second Order Hamiltonian Systems
PublicationWe show the existence of homoclinic type solutions of a class of inhomogenous second order Hamiltonian systems, where a C1-smooth potential satisfies a relaxed superquadratic growth condition, its gradient is bounded in the time variable, and a forcing term is sufficiently small in the space of square integrable functions. The idea of our proof is to approximate the original system by time-periodic ones, with larger and larger...
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LLA : A New Anypath Routing Scheme Providing Long Path Lifetime in VANETs
PublicationVehicular ad-hoc networks (VANETs) are a promising solution to improve the road traffic safety, reduce the environmental pollution, or simply provide the on-board infotainment services. However, these actions are often not possible due to high mobility of vehicles causing frequent failures of VANET links. In this paper, we focus on anypath routing to improve the reliability of multihop VANET communications. In particular, the paper...
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Dipole-driven dynamics for near-threshold electron/positron interactions with pyrimidinic DNA bases: a path to compound formations
PublicationCalculations are reported for electron and positron scattering from isolated cytosine and thymine, where the two pyrimidinic single-ring DNA bases, in the gas-phase at energies near the elastic threshold, they reveal the special features of the dipole-driven scattering states. All molecules examined exhibit, in fact, supercritical (>1.67 D) permanent dipoles which can therefore also support, below threshold, excited bound compound...
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Monitoring of organic pollutants in coastal waters of the Gulf of Gdańsk, Southern Baltic.
PublicationPrzedstawiono zmiany zawartości zanieczyszczeń organicznych (np. VOC, PAH, PCB, chlorofenoli) w wodach Zatoki Gdańskiej na przestrzeni 5-ciu lat. Zawartość VOX i VOC zmieniała się od kilku ngdm-3 do kilkuset ngdm-3, podczas gdy zawartość chlorofenoli fenoksykwasów była na poziomie kilku ngdm-3. W większości próbek nie wykryto PCB.
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Safety Analysis for the Operation Process of Electronic Systems Used Within the Mobile Critical Infrastructure in the Case of Strong Electromagnetic Pulse Impact
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Modelling the Safety Levels of ICT Equipment Exposed to Strong Electromagnetic Pulses
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Cooperation of a Non-Linear Receiver with a Three-Phase Power Grid
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Assessing the Operation System of Fire Alarm Systems for Detection Line and Circuit Devices with Various Damage Intensities
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Designing of an effective structure of system for the maintenance of a technical object with the using information from an artificial neural network
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Determining Information Quality in ICT Systems
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The Impact of Strong Electromagnetic Pulses on the Operation Process of Electronic Equipment and Systems Used in Intelligent Buildings
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