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Search results for: THIN-WALLED ELEMENTS
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Modeling and Strength Calculations of Parts Made Using 3D Printing Technology and Mounted in a Custom-Made Lower Limb Exoskeleton
PublicationThis study is focused on the application of 3D-printed elements and conventional elements to create a prototype of a custom-made exoskeleton for lower limb rehabilitation. The 3D-printed elements were produced by using Fused Deposition Modeling technology and acrylonitrile butadiene styrene (ABS) material. The scope of this work involved the design and construction of an exoskeleton, experimental testing of the ABS material and...
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Oxygen biosensor based on carbon nanotubes directly grown on graphitic substrate
PublicationFilms of carbon nanotubes were synthesized on the graphitic substrates by CVD method in the presence of catalyst. Two different catalysts were used, that is nickel and iron, supported on graphitic substrates. The as-obtained nanotubes were analyzed by SEM imaging with EDX and Raman spectroscopy. The results revealed their multi-walled morphology. Free radical reaction was carried out in order to chemically functionalize synthesized...
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Formation and Growth of the Crack in Bonded Joints Under Mode I Fracture: Substrate Deflection at Crack Vicinity
PublicationAdhesive bonding is now commonly used in aircraft, cars, boats, etc. In these applications, thin panels are often bonded. In such thin structures, heterogeneous mechanical loading along the bondline edge (or potential crack front), is likely to arise due to 3D structural effects. The crack front and its vicinity is a special region, in that it is where structural properties of the adherend material meet those of the adhesive (discontinuity)....
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The influence of thermal conditions on V2O5 nanostructures prepared by sol-gel method
PublicationThis work presents the result of structure investigations ofV 2O5 nanorods grown from thin films and powders prepared by sol-gel method. To examine the best temperature of nanorods crystallization, thin films deposited by spin-coating method on quartz glass or silicon substrates and bulk xerogel powders were annealed at various temperatures ranging from 100∘C to 600∘C. The structure of the samples was characterized by X-ray diffraction...
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Cast iron in the 19th-century building equipment
PublicationCast iron is a material, characteristics of which enable to receive extremely artistic elements. It maintains good strength properties at the same time. That combination of these seemingly contrary traits makes it a commodity that was widely used in the 19th century industry and architecture. These usages were not only as decorative elements, technical and structural ones. The production of new household utilities started, which...
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Linking of adjacent three-storey buildings for mitigation of structural pounding during earthquakes
PublicationThe reports after major earthquakes indicate that the earthquake-induced pounding between insufficiently separated buildings may lead to significant damage or even total collapse of structures. An intensive study has recently been carried out on mitigation of pounding hazards so as to minimize the structural damages or prevent collisions at all. The aim of this paper is to investigate the effectiveness of the method when two adjacent...
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On the Agile Mindset of an Effective Team – An Industrial Opinion Survey
PublicationIn this paper we present the results of an opinion survey among 52 agile practitioners who evaluated the importance of 26 selected elements of the agile mindset to the effectiveness of an agile team. In total, we have identified 70 unique agile mindset elements based on 11 literature sources and 5 interviews with industry experts. 7 elements belonged to the “support for business goals” category, 20 to the “relationships within...
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THE CONCEPT OF MODELING OF SNOW IMPACT ON THE STRUCTURE OF THE SUSPENDED TAURON ARENA ROOF IN CRACOW
PublicationThe article presents studies and numerical simulations on modeling snow influence on TAURON ARENA suspended roof structure in Cracow. The scope of work includes experimental tests, functions solutions taking into account various cases of snow impact according to PN and EC, as well as numerical simulations for the sport and entertainment arena in the Czyzyny district. The FEM roof structure model developed in the SOFISITK software...
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Pounding mitigation of a short-span cable-stayed bridge using a new hybrid passive control system
PublicationThis paper investigates the effectiveness of a new hybrid passive control system on the seismic response of an existing steel cable-stayed bridge considering the pounding effect. The proposed hybrid passive control system comprises a seismic isolator and a metallic damper. The bridge is located in a high seismic zone and has suffered several damages including the earthquake-induced pounding damage during the 1988 earthquake....
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Wave propagation in plate structures for crack detection.
PublicationW pracy przedstawiono analizę propagacji fali poprzecznej w płycie z pęknięciem. Do modelowania zagadnienia zastosowano metodę elementów spektralnych.
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Numerical analysis of elastic wave propagation in unbounded structures
PublicationThe main objective of this paper is to show the effectiveness and usefulness of the concept of an absorbing layer with increasing damping (ALID) in numerical investigations of elastic wave propagation in unbounded engineering structures. This has been achieved by the authors by a careful investigation of three different types of structures characterised by gradually increasing geometrical and mathematical description complexities....
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An optimal form of the finite element mass matrix in the analysis of longitudinal vibrations of rods
PublicationIn this paper, an attempt is made to find the optimal form of the mass matrix of a rod finite element, which allows one to obtain the smallest errors in the longitudinal frequency determination of natural vibrations of any boundary conditions within the whole range of determined frequencies. It is assumed that the mass matrix can be treated as a linear combination of the consistent and diagonal matrices. Based on analytical considerations,...
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Wave propagation in plate structures for crack detection
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Numerical analysis of elastic wave propagation in unbounded structures
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Certain numerical issues of wave propagation modelling in rods by the Spectral Finite Element Method
PublicationW pracy omówiony zagadnienia związane z modelowaniem propagacji fal sprężystych metodą Spektralnych Elementów Skończonych. Przedstawiono wpływ postaci macierzy mas na błędy rozwiązania. Omówiono zakres stosowalności modeli.
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Propagation of in-plane waves in an isotropic panel with a crack
PublicationW pracy przedstawiono model tarczowego elementu spektralnego do analizy propagacji fali wzdłuznej w panelach z uszkodzeniami.
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A coupled constitutive model for fracture in plain concrete based on continuum theory with non-local softening and eXtended Finite Element Method
PublicationThe paper presents a constitutive model for concrete which combines a continuous and discontinuous fracture description. In a continuum regime, two different constitutive laws were used. First, a plasticity model with a Rankine failure criterion and an associated fl ow rule was used. Second, a constitutive law based on isotropic damage mechanics was formulated. In order to capture the width of a localized zone and to obtain mesh-independent...
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Numerical analysis of size effect in RC beams scaled along height or length using elasto-plastic-damage model enhanced by non-local softening.
PublicationArtykuł omawia wyniki numeryczne dotyczące efektu skali w belkach żelbetowych uzyskane stosując metodę elementów skończonych. Dwuwymiarowe obliczenia wykonano dla belek żelbetowych podczas 4-punktowego zginania. Belki były skalowane wzdłuż wysokości lub długości. Beton został opisany prawem sprężysto-plastycznym z degradacją sztywności, rozszerzonym o nielokalność w osłabieniu. Wyniki numeryczne zostały porównane z wynikami doświadczalnymi....
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FE analysis of reinforced concrete corbels with enhanced continuum models
PublicationW artykule pokazano wyniki MES symulacji wsporników żelbetowych. Zachowanie wsporników modelowano przy zastosowaniu 3 różnych modeli betonu: sprężysto-plastycznego, degradacji sprężystej i rozmytych rys. Modele rozszerzono o długość mikrostruktury przy zastosowaniu teorii nielokalnej. Wyniki numeryczne porównano z doświadczeniami z literatury.
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FE analysis of size effects in reinforced concrete beams without shear reinforcement based on stochastic elasto-plasticity with non-local softening.
PublicationW artykule przedstawiono wyniki analizy MES dotyczącej deterministycznego i statystycznego efektu skali w żelbetowych belkach bez zbrojenia na ścinanie. W analizie zastosowano prawo sprężysto-plastyczne z nielokalnym osłabieniem. Wyniki analizy porównano z doświadczeniami i modelem skali Bazanta.
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Wpływ stopowania laserowego z użyciem nanorurek węglowych stopu Ti13Nb13Zr do zastosowań biomedycznych na jego wybrane własności mechaniczne
PublicationDo eksperymentu użyto stopu tytanu Ti13Nb13Zr, który ze względu na swój skład chemiczny i właściwości mechaniczne stanowi materiał do zastosowań w inżynierii medycznej. Celem pracy była ocena wpływu stopowania laserowego stopu Ti13Nb13Zr z powłoką z wielościennych nanorurek węglowych na jego właściwości mechaniczne (chropowatość, nanotwardość, moduł Younga). Do wytworzenia powłoki węglowej wykorzystano metodę osadzania elektroforetycznego (EDP)....
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Wide-field magnetometry using nitrogen-vacancy color centers with randomly oriented micro-diamonds
PublicationMagnetometry with nitrogen-vacancy (NV) color centers in diamond has gained significant interest among researchers in recent years. Absolute knowledge of the three-dimensional orientation of the magnetic field is necessary for many applications. Conventional magnetometry measurements are usually performed with NV ensembles in a bulk diamond with a thin NV layer or a scanning probe in the form of a diamond tip, which requires a...
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Laser reflectance interferometry system with a 405 nm laser diode for in-situ measurement of CVD diamond thickness
PublicationIn situ monitoring of the thickness of thin diamond films during technological processes is important because it allows better control of deposition time and deeper understanding of deposition kinetics. One of the widely used techniques is laser reflectance interferometry (LRI) which enables non-contact measurement during CVD deposition. The authors have built a novel LRI system with a 405 nm laser diode which achieves better...
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A model of liquid film breakdown formed due to impingement of a two-phase jet on a horizontal surface
PublicationThe present work aims to provide an explanation to the phenomenon of breakdown of the thin liquid film created by impinging two-phase, liquid-gas jet. Existing in the literature models describe merely thebreakdown of single phase liquid films. The model presented here is based on examination of mass and energy equations under the applied criterion of the minimum of total energy. That allows to determinethe minimum thickness of...
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The low coherence Fabry-Pérot interferometer with diamond and ZnO layers
PublicationThe authors present a fiber-optic Fabry-Pérot interferometer built with the application of diamond and zinc oxide (ZnO) thin layers. Thin ZnO films were deposited on the tip of a standard telecommunication single-mode optical fiber (SMF- 28) while the diamond layer was grown on the plate of silicon substrate. Investigated ZnO layers were fabricated by atomic layer deposition (ALD) and the diamond films were deposited using Microwave...
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Spectroscopic Study of Plasma Polymerized a-C:H Films Deposited by a Dielectric Barrier Discharge
PublicationPlasma polymerized a-C:H thin films have been deposited on Si (100) and aluminum coated glass substrates by a dielectric barrier discharge (DBD) operated at medium pressure using C2Hm/Ar (m = 2, 4, 6) gas mixtures. The deposited films were characterized by Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS), Raman spectroscopy, and ellipsometry. FT-IRRAS revealed the presence of sp3 and sp2 C–H stretching and...
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On the Buckling Response of Axially Pressurized Nanotubes Based on a Novel Nonlocal Beam Theory
PublicationIn the present study, the buckling analysis of single-walled carbon nanotubes (SWCNT) on the basis of a new refined beam theory is analyzed. The SWCNT is modeled as an elastic beam subjected to unidirectional compressive loads. To achieve this aim, the new proposed beam theory has only one unknown variable which leads to one equation similar to Euler beam theory and is also free from any shear correction factors. The equilibrium...
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Hybrid battery based on arylated carbon nanotubes and laccase
PublicationSingle-walled carbon nanotubes (SWCNT) were covalently modified with anthracene and anthraquinone and used for the construction of cathodes for biocatalytic reduction of dioxygen. The nanotubes with aromatic groups casted onto the electrode increased the working surface of the electrode and enabled efficient direct electron transfer (DET) between the enzyme and the electrode. The aryl groups enter the hydrophobic pocket of the...
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Partially prestressed concrete beams with bonded and unbonded strands
PublicationThis article relate the tests of partially prestressed concrete beams. There is presented the research programme - geometry of elements, method of loading, the materials and variables. There have been shown preliminary test results of prestressed concrete elements with bonded and unbonded strands, and compared to the test results of R.C. beam.
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A large family of filled skutterudites stabilized by electron count
PublicationThe Zintl concept is important in solid-state chemistry to explain how some compounds that combine electropositive and main group elements can be stable at formulas that at their simplest level do not make any sense. The electronegative elements in such compounds form a polyatomic electron-accepting molecule inside the solid, a ‘polyanion’, that fills its available energy states with electrons from the electropositive elements...
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Nucleation and growth of CVD diamond on fused silica optical fibres with titanium dioxide interlayer
PublicationNucleation and growth processes of thin diamond films on fused silica optical fibres have been investigated. Fibres were coated with diamond film using microwave plasma enhanced chemical vapour deposition (µPE CVD) system. Since the growth of diamond on the fused silica glass requires high seeding density, two types of glass pre-treatment were applied: titanium dioxide (TiO2) interlayer deposition and sonication in nanodiamond...
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Titania Nanotubes/Hydroxyapatite Nanocomposites Produced with the Use of the Atomic Layer Deposition Technique: Estimation of Bioactivity and Nanomechanical Properties
PublicationTitanium dioxide nanotubes/hydroxyapatite nanocomposites were produced on a titanium alloy (Ti6Al4V/TNT/HA) and studied as a biocompatible coating for an implant surface modification. As a novel approach for this type of nanocomposite fabrication, the atomic layer deposition (ALD) method with an extremely low number of cycles was used to enrich titania nanotubes (TNT) with a very thin hydroxyapatite coating. X-ray diffraction (XRD)...
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In-situ monitoring of electropolymerization processes at boron-doped diamond electrodes by Mach-Zehnder interferometer
PublicationIn this work, the Mach-Zehnder interferometer was designed to monitor the electrochemical processes conducted at boron-doped diamond electrode surface. The diamond electrodes were synthesized via Microwave Plasma-Assisted Chemical Vapor Deposition on optical grade quartz glass. The achieved transmittance in working are of diamond electrodes reached 55 %. A cage system-based Mach-Zehnder interferometer was used which allowed the...
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Laser induced formation of copper species over TiO2 nanotubes towards enhanced water splitting performance
PublicationWe proposed fast and scalable route where the ordered TiO2 nanotubes coated with thin copper layers were annealed by the laser beam of 355 nm wavelength at different fluencies in the range of 15–120 mJ/cm2. As a result, copper species are integrated with the titania substrate and the formed material exhibits unique optical absorption bands in the visible range. Moreover, X-ray photoelectron spectroscopy analysis reveals the formation...
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The Influence of Shear Deformation in analysis of plane frames
PublicationThe focus of the paper is to investigate the influence of shear deformation effect on the distribution of internal forces and frame deformation. To estimate shear deformation effect, the Timoshenko beam theory and the concept of shear deformation coefficients are used. Analysis of example frames gives the possibility to evaluate what have the most impact on size of shear deformation and in which type of frames the shear deformation...
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Torsional stability capacity of a nano-composite shell based on a nonlocal strain gradient shell model under a three-dimensional magnetic field
PublicationThis paper considers a single-walled composite nano-shell (SWCNS) exposed in a torsional critical stability situation. As the magnetic field affects remarkably nanostructures in the small size, a three-dimensional magnetic field is assessed which contains magnetic effects along the circumferential, radial and axial coordinates system. Based on the results of the nonlocal model of strain gradient small-scale approach and the first-order...
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Empirically adjusted and consistent set of EHT valence orbital parametersfor all elements of the periodic table. Modelling Simul. Mater. Sci. Eng. [online]. 2004 vol. 12 [dostęp..] s. 21-32, 3 rys. 3 tab. bibliogr. 35 poz. Dostępny w Internecie stacks.iop.org/MSMSE/12/21.ISSN 0965-0393 Jednorodny skorygowany empirycznie zbiór parametrów EHT dla orbitali walen- cyjnych pierwiastków.
PublicationModel atomu HFS został zmodyfikowany poprzez przypisanie każdemu z atomówindywidualnego parametru ŕ. Wartości ŕ dobrano w oparciu o pierwszy poten-cjał jonizacji atomu. Parametry EHT wyznaczono w oparciu o tak zmodyfikowa-ny model HFS.
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Multifrequency Wideband Sonar Array
PublicationThis paper describes of new approach to Multifrequency Wideband Arrays (MWA),applied piezocomposite technologies of the array elements. MWA operating in transmitting(Tx) and receiving (Rx) mode on two or three bands, requires state-of-the-art technology andefficient array designing than conventional array in which separate arrays for every band oreven separate Tx and Rx transducers/arrays are used. The new piezocomposite elements...
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Identification of the Agile Mindset and Its Comparison to the Competencies of Selected Agile Roles
PublicationIn this paper we present the results of the identification and evalua-tion of the elements of an agile mindset as well as its comparison to the compe-tence models for the roles of Scrum Master, Product Owner and agile analyst. We have identified 70 unique agile mindset elements from literature and 5 in-terviews with experts. Based on an opinion survey among 52 agile practitioners we evaluated the importance of 26 selected elements...
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The central server of the Border Guard's distributed multimedia system for monitoring and visualisation of ongoing and archival events
PublicationThe paper presents the architecture and functionalities of the central server (CENTER) of the distributed system for the Polish Border Guard (BG) for monitoring maritime areas. The overall system has been extended to incorporate, apart from map data, also different multimedia elements such as video from cameras or audio from telephone connections operated by BG units. This requires new system elements: Archive Servers for storing...
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Simulation investigation of perovskite-based solar cells
PublicationThree models of thin-layer lead-halide perovskite solar cells with different electron-transport layers (TiO2,SnO2,ZnO) were investigatedby the simulation method. The perovskite layer thickness was optimized for all the systems. The analysis of the standard photovoltaic cell performanceparameters at various operating temperatures was performed. The best performance was achieved for the system with theSnO2conductive layer.
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Wideband crossover structure with double ring resonators
PublicationThe structure of a four-port microstrip crossover is presented. The device is composed of two ring resonators, one circular and one built from meander lines, connected by four straight lines. The equivalent circuit model of the crossover is derived. The structure is designed on thin and flexible substrate to allow it to bend. The possibility of applying the device on curved surfaces is tested experimentally.
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Analiza nośności zabytkowych fundamentów w kontekście jakości użytych zapraw Analysis of the Load-Bearing Capacity of Historical Foundations in the Context of the Quality of Mortar Used
PublicationStructures of historical buildings usually have the form of masonry elements. The weakest component of such elements is mortar, especially in stone foundations, which were often used in the with a focus on the modeling of mortar as a joint connecting stones in a characteristic medieval foundation. Different types of mortar: cement, cement-lime, lime and gypsum mortars, were examined. A numerical analysis was carried out on the...
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Room temperature depinning of the charge-density waves in quasi-two-dimensional 1T-TaS2 devices
PublicationWe report on the depinning of nearly commensurate charge-density waves in 1T-TaS2 thin films at room temperature. A combination of the differential current–voltage measurements with the low-frequency noise spectroscopy provides unambiguous means for detecting the depinning threshold field in quasi-2D materials. The depinning process in 1T-TaS2 is not accompanied by an observable abrupt increase in electric current—in striking contrast...
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A facile method for Tauc exponent and corresponding electronic transitions determination in semiconductors directly from UV–Vis spectroscopy data
PublicationIn this work, a facile method allowing for estimation of the exponent in the Tauc equation directly from the UV–vis spectra is presented. It is based on the Taylor expansion of the logarithmic version of the Tauc equation. The Tauc exponent is calculated from the tangent slope of the absorption data. Knowledge of this coefficient provides information about the optical transition types and is used as an input for the calculations...
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Application of boron-doped diamond film and ZnO layer in the Fabry-Pérot interferometer
PublicationIn this article there have been presented the use of boron-doped diamond films for sensor applications. The low-finesse Fabry-Pérot interferometer working in the reflective mode has been implemented. Two kinds of reflective layers have been elaborated: boron-doped diamond thin films and zinc-oxide (ZnO) layer. Thin ZnO layers were deposited by Atomic Layer Deposition (ALD) on the face of a standard telecommunication single-mode...
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ZnO coated fiber optic microsphere sensor for the enhanced refractive index sensing
PublicationOptical fiber-based sensors are expected to become key components in the control of industrial processes,and the tuning and the enhancement of their sensing properties are crucial for the further developmentof this technology. Atomic Layer Deposition (ALD), a vapor phase technique allowing for the deposition ofconformal thin films, is particularly suited for the deposition of controllable thin films on challenging sub-strates....
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CAUSALITY IN MODELS OF THERMAL PROCESSES IN SHIP ENGINE ROOMS WITH THE USE OF BOND GRAPH (BG) METHOD
PublicationWith a single approach to modeling elements of different physical nature, the method of Bond Graph (BG) is particularly well suited for modeling energy systems consisting of mechanical, thermal, electrical and hydraulic elements that operate in the power system engine room. The paper refers to the earlier presented new concept of thermal process modeling using the BG method. The authors own suggestions for determining causality...
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Implementing decisional trust: a first approach for smart reliable systems
PublicationIn this article, we introduce the necessary elements that must be integrated in order to achieve a decisional technology that is trustworthy. Thus, we refer to such technology as decisional trust. For us, decisional trust can be achieved through the use of elements such as the decisional DNA, reflexive ontologies, and security models; and therefore, we present in this article a framework that was used for the implementation of...
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The structure of the data flow in integrated urban traffic management systems – the case of TRISTAR system
PublicationThe purpose of the article is to offer some insight into the data flow architecture in the Tri-City’s integrated traffic management system called TRISTAR. To that end selected elements of TRISTAR are identified and described as well as the structure for collecting and exchanging data within different sub-systems. Finally, the article highlights how the TRISTAR system can be extended by adding new elements and modules.