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Wyniki wyszukiwania dla: BOUNDARY ELEMENT ANALYSIS
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Comparison of heat transfer characteristics in surface cooling using microjets with water, ethanol and HFE7100 as test fluids
PublikacjaAccurate control of cooling parameters is required in ever wider range of technical applications. It is known that reducing the dimensions of the size of nozzle leads to an increase in the economy of cooling and improves its quality. Present study describes research related to the design and construction of the nozzles and microjet study, which may be applied in many technical applications such as in metallurgy, electronics, etc....
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Effects of Ni-NCAL and Ni–Ag electrodes on the cell performances of low-temperature solid oxide fuel cells with Sm0.2Ce0·8O2-δ electrolyte at various temperatures
PublikacjaThree low-temperature solid oxide fuel cells are built using Sm0.2Ce0·8O2-δ (SDC) as the electrolyte. Cell A is symmetrical and features Ni–LiNi0.8Co0·15Al0·05O2 (Ni–NCAL) electrodes, Cell B comprises a Ni–NCAL anode and a Ni–Ag cathode, and Cell C is fabricated using a Ni–NCAL cathode and a Ni–Ag anode. The ohmic resistance and polarization resistance (Rp) of Cells B and C are significantly higher than those of Cell A. The reduction...
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Mathematical model to assess energy consumption using water inflow-drainage system of iron-ore mines in terms of a stochastic process
PublikacjaPurpose is to develop a unified mathematical model to assess energy efficiency of a water inflow-drainage process as the real variant of stochastic method for water pumping from underground workings of iron-ore mines. Methods. The research process was based upon the methods of probability theory as well as stochastic modelling methods. The stochastic function integration has been reduced to summation of its ordinates and further...
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Detection and time/frequency analysis of electric fields in the ground
PublikacjaThis paper sets out to detect and characterize electric fields in the ground (such as stray current fields) using a tandem time/frequency method of signal analysis. Results were obtained from investigations performed in the presence of a generated electric field with controlled variable characteristics, and in the presence of an electric field generated by a tramline. The analysis of measurement registers was performed using Short‐Time...
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A LABORATORY STAND FOR THE ANALYSIS OF DYNAMIC PROPERTIES OF THERMOCOUPLES
PublikacjaIn the present elaboration, problems connected with measurements of high variable temperatures of gases are introduced and the impact of dynamic properties of different construction solutions of thermoelements on the accuracy of the measurements is considered. A laboratory stand built within research under doctoral thesis, destined for analysis of dynamic properties of thermocouples is also described. Results of numerical simulation...
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Modelling and analysis of medium frequency transformers for power converters
PublikacjaThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
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Multimodal Particle Swarm Optimization with Phase Analysis to Solve Complex Equations of Electromagnetic Analysis
PublikacjaIn this paper, a new meta-heuristic method of finding roots and poles of a complex function of a complex variable is presented. The algorithm combines an efficient space exploration provided by the particle swarm optimization (PSO) and the classification of root and pole occurrences based on the phase analysis of the complex function. The method initially generates two uniformly distributed populations of particles on the complex...
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Analytical applications of smartphones for agricultural soil analysis
PublikacjaSoil is one of the most important farming resources. Appropriate managing of its quality promotes productive and sustainable agriculture. The valuable farm practice in soil quality managing is based on regular soil analysis with the aim to determine the exact amount of nutrients or other chemical, physical and biological soil properties. Soil analysis usually requires samples collection at desired sampling depth following by samples...
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Analysis of Crash Computation on a Basis of the Pronciple of Linear Momentum and Kinetic Energy
PublikacjaThe article shows the calculation of a vehicle crash with a fixed pile, modelled by the finite element method. There were compared during the crash simulations changes in kinetic energy, as well as – changes in linear momentum and its derivative, with respect to time. Calculations were made in the HyperWorks CAE software environment. The obtained results show influence of various body parts and devices of the deceleration on...
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NON-LINE ANALYSIS OF STIFFNESS IN COMPRESSION CONDITIONS
PublikacjaThe analyzes were aimed at demonstrating the influence of parameters describing the deformation of the structure on the uncertainty of critical force, and the impact of technological imperfections on stress uncertainty in compression conditions. In a linear buckling analysis, the problem is considered only for the initial, permanent state of the stiffness matrix. In the case of demonstrating the influence of initial deformations...
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Detection of the Bee Queen Presence Using Sound Analysis
PublikacjaThis work describes the system and methods of data analysis we use for beehive monitoring. We present overview of the hardware infrastructures used in hive monitoring systems and we describe algorithms used for analysis of this kind of data. Based on acquisited signals we construct the application that is capable to detect an absence of honey bee queen. We describe our method of signal analysis and present results that allow us...
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Analysis of degaussing process of ferromagnetic objects
PublikacjaResults of the analytical and numerical analysis of the degaussing process phenomena of ferromagnetic objects were presented in this paper. The screening effectiveness of the electromagnetic field of magnetic screens in most cases depends on thickness, conductivity, magnetic permeability of the screen and angular frequency of degaussing currents. The magnetic field inside thin-layer ferromagnetic object was presented in this paper....
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Usage of concentrated spectrogram for analysis of acoustical signals
PublikacjaA novel precise method of signal analysis in the time-frequency domain is presented. A signal energy distribution is estimated by discard and displacement of energy parts of the classical spectrogram. A channelized instantaneous frequency and a local group delay are used in order to energy replacement. Additionally, newly introduced representations such as: a channelized instantaneous bandwidth and a local group duration are used...
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A Mesh Deformation Technique Based on Solid Mechanics for Parametric Analysis of High-Frequency Devices With 3-D FEM
PublikacjaIn this paper, a versatile technique for mesh defor- mation is discussed, targeted at the electromagnetic (EM) field simulation of high-frequency devices using the 3-D finite element method (FEM). The approach proposed applies a linear elasticity model to compute the displacements of the internal mesh nodes in 3-D when the structure geometry is changed. The technique is compared with an alternative approach...
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FEM analysis of composite materials failure in nonlinear six field shell theory
PublikacjaThe monography deals with the problem of failure initiation in thin laminated composites. Known techniques of laminate structures modelling are briefly characterised. Eventually, shell based approach is chosen for the purpose of the description of the composite structures behaviour, as it predicts their deformation and states of stress effectively in a global sense. The nonlinear six parameter shell theory (6p theory) with asymmetric...
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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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Differential analysis of dynamic immittance spectra
PublikacjaThis work presents a new approach to the analysis of immittance spectrograms of systems characterised by non-stationarity. The possibility of linking the evolution of the immittance response with changes in the parameters describing the system is achieved by introducing a spectrum in differential form. By using the above procedure, it becomes possible to separate elements with a dependence (or lack thereof) from an independent...
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Diagnostic Analysis of Exhaust Gas with A Quick-Changing Temperature from a Marine Diesel Engine Part II / Two Factor Analysis
PublikacjaThe article presents a continuation of research carried out to determine the effect of input parameters (changes in engine structure parameters) on selected output parameters (diagnostic measures), based on quickly changing exhaust gas temperature. A method of determining the simultaneous influence of two input factors (the structure parameter and the engine load) on one output factor was presented, as well as an evaluation...
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Application of the DSC analysis of thermoplastic polyurethane elastomers to a comparative study of their technological properties
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Failure analysis and modernization of high-pressure hydraulic press for drilling tubes testing
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Experimental and numerical analysis of the modified TB32 crash tests of the cable barrier system
PublikacjaRoad restraint systems, including safety barriers, are one of the means used to improve road safety. Currently, they can be allowed to general use after passing the specific crash tests. However, it is always important and desirable to evaluate their performance under various realistic conditions, which can happen on the roads. In this study, the behaviour of the cable barrier system in impact conditions different than assumed...
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Analysis of Interspike-Intervals for the General Class of Integrate-and-Fire Models with Periodic Drive
PublikacjaWe study one-dimensional integrate-and-fire models of the general type x˙=F (t, x) and analyze properties of the firing map which iterations recover consecutive spike timings. We impose very week constraints for the regularity of the function F (t, x), e.g. often it suffices to assume that F is continuous. If additionally F is periodic in t, using mathematical study of the displacement sequence of an orientation preserving circle...
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FEA analysis of the multicell piezoelectric motor
PublikacjaThe presented paper concerns a design, modeling and chosen tests of the prototype multicell piezoelectric motor (MPM). The principle of operation based on three independent traveling wave actuators is presented. The main materials and technologies used in the fabrication process are described. The structure of the motor is modeled using static and modal FEM analysis. The process of traveling wave generation in the MPM structure...
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Quantification of Compatibility Between Polymeric Excipients and Atenolol Using Principal Component Analysis and Hierarchical Cluster Analysis
PublikacjaAn important challenge to overcome in the solid dosage forms technology is the selection of the most biopharmaceutically efficient polymeric excipients. The excipients can be selected, among others, by compatibility studies since incompatibilities between ingredients of the drug formulations adversely affect their bioavailability, stability, efficacy, and safety. Therefore, new, fast, and reliable methods for detecting incompatibility...
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Functional safety analysis including human factors
PublikacjaThe article addresses selected aspects of human factors that should be taken into account during the design of safety-related functions for a complex hazardous installation and its protections. In such installations the layer of protection analysis (LOPA) methodology is often used for simplified risk analysis based on defined accident scenarios. To control the risk the safety instrumented functions (SIFs) are identified and their...
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Analysis of magnetic field of Helmholtz's coils
PublikacjaThe 3-axis fluxgate magnetometer requires conducting a precise calibration in the magnetic field whose value is determined and which is characterized by the high uniformity of the distribution of the field, especially along the axis of the sensors. The generation of the magnetostatic field characterized by the high uniformity, can be achieved by using the Helmholtz's coils. The requirements of the uniformity of distribution of...
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Earth wires currents calculation by tableau analysis
PublikacjaThe paper presents a new method to compute a phase-to-earth fault current distribution in overhead transmission line. The method is based on the tableau analysis of an unbalanced, multi-wire model of a transmission line. It allows for the calculation of current distribution in overhead earth wires along the transmission line. Additionally, it may be used to calculate currents in a tower’s earthing system as well as voltages over...
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ANALYSIS OF THE INCREASE OF CONSTRUCTION COSTS IN URBAN REGENERATION PROJECTS
PublikacjaThe subject of this paper is the analysis and evaluation of the reasons for construction costs increases in urban regeneration projects. The analysis considers major refurbishments of real estates’, as well as heavy repair and modernization of the road system. For the period mentioned, the costs from works and expenditure schedules were compared with the costs of additional works, which shows the percentage cost increase in relation...
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Ideologia Towarzystwa Fabianów i jej źródła jako istotny element kształtowania się myśli socjaldemokratycznej
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Discrete-Element bonded-particle Sea Ice model DESIgn, version 1.3a – model description and implementation
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Discrete-Element bonded particle Sea Ice model DESIgn, version 1.3 – model description and implementation
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Wave-induced stress and breaking of sea ice in a coupled hydrodynamic discrete-element wave–ice model
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Finite element method (FEM) implementation in some chosen areas in dental tytanium-ceramic crown design
PublikacjaAnaliza rozkładu naprężeń wykazała, że szczególnie duże spiętrzenia naprężeń powstają w częściach przyszyjkowych tytanowo-ceramicznej korony stomatologicznej. W przyszyjkowej części modelu występują największe naprężenia rozciągające, szczególnie niebezpieczne dla ceramiki nieodpornej na tego typu obciążenia. Mogą one stanowić przyczynę spękania i odprysków w części przyszyjkowej korony. Wyniki symulacji komputerowej metodą MES...
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Rozliczalność władzy politycznej jako element wzmocnienia demokracji i podwyższenia jej jakości: przykład Polski
PublikacjaCelem artykułu jest wskazanie odpowiednich niezbędnych do wdrożenia w polskiej sferze politycznej mechanizmów rozliczalności, które odpowiadają zmianom cywilizacyjnym. Problem badawczy dotyczył rozważenia zasadności wdrożenia mechanizmów i narzędzi pełnej rozliczalności sfery politycznej, opierających się na elementach e-demokracji. Podstawową metodą była krytyczna analiza i przegląd literatury....
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Energia słoneczna jako innowacyjny element kreacji przestrzeni publicznej miasta = Energy of sunlight in future city
PublikacjaParadoksem współczesnych praktyk projektowych w publicznej prestrzeni miast jest fakt oparcia siły wyrazu elementów wielkoprzestrzennych oraz małej architektury, głównie na zastosowaniu światła sztucznego...czyżby została już zapomniana dawna sztuka kreacji nastroju światłem słonecznym ? Analiza dotyczy studium przypadku dwu nowych realizacji rzeżbiarskich w mieście gdańsku.(dokumentacja fotograficzna e. Novokunskiego).
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Finite element method simulations of various cases of crash tests with N2/W4/A steel road barrier
PublikacjaThe subject of this study is performance of N2/W4/A steel road safety barrier investigated in numerical simulations. System was checked under several types of initial conditions, which were assumed basing on the TB11 and TB32 normative crash tests. The main goal of present study is to investigate the relationship between initial conditions (angle and velocity) of the impact and the severity indices (associated to the vehicle occupant) during...
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Identification of the featured-element in fine road dust of cities with coal contamination by geochemical investigation and isotopic monitoring
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Analysis of the process of water entry of an amphibious vehicle
PublikacjaThe paper presents a method of computational and experimental analysis of the process of water entry of an amphibious vehicle. The computational method is based on the Reynolds Averaged Navier-Stokes Equations (RANSE) solver and the xperiment was carried out in the towing tank at Ship Design and Research Centre S.A. with the use of a scale model. The analysis was focused on the safety of water entry, i.e. the maximum pitch and...
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Error analysis for European IGS stations
PublikacjaEach of the GPS time series that describes the changes of topocentric components consists of a deterministic and a stochastic part, whose character influences the errors of the deterministic parameters. As to the uncertainties of reliable velocities of permanent satellite station systems, surveys that estimate and take into account any dependencies that may affect subsequent operational efficiency are very important. For this analysis,...
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Novel analysis methods of dynamic properties for vehicle pantographs
PublikacjaTransmission of electrical energy from a catenary system to traction units must be safe and reliable especially for high speed trains. Modern pantographs have to meet these requirements. Pantographs are subjected to several forces acting on their structural elements. These forces come from pantograph drive, inertia forces, aerodynamic effects, vibration of traction units etc. Modern approach to static and dynamic analysis should...
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Combined pH/organic solvent gradient HPLC in analysis of forensic material
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Multiresolution analysis and adaptive estimation on a sphere using stereographic wavelets
PublikacjaWe construct an adaptive estimator of a density function on d dimensional unit sphere Sd (d ≥ 2), using a new type of spherical frames. The frames, or as we call them, stereografic wavelets are obtained by transforming a wavelet system, namely Daubechies, using some stereographic operators. We prove that our estimator achieves an optimal rate of convergence on some Besov type class of functions by adapting to unknown smoothness....
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The Point Estimate Method in a Reticulated Shell Reliability Analysis
PublikacjaThe objective of this paper is to present an application of the point estimate method (PEM) to determine the probabilistic moments for engineering structures. Reliability analysis is illustrated by two examples: an estimation of the critical force in linear elastic buckling analysis and a reticulated shell limit load determinations. Calculations were also made using Monte Carlo method. It has been shown the practical usefulness...
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Deformation Analysis of a Composite Bridge during Proof Loading Using Point Cloud Processing
PublikacjaRemote sensing in structural diagnostics has recently been gaining attention. These techniques allow the creation of three-dimensional projections of the measured objects, and are relatively easy to use. One of the most popular branches of remote sensing is terrestrial laser scanning. Laser scanners are fast and efficient, gathering up to one million points per second. However, the weakness of terrestrial laser scanning is the...
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Space syntax analysis - methodology of understanding the space
PublikacjaNowadays space is considered as a net of connections between different areas. The questions how to delineate its character and how it is possible to objectively compare two spaces is the matter under consideration. This was the reason for creating new theories about the structure of place. "Space syntax analysis" (SSA) or simply "Space Syntax" defines a number of theories and research areas devoted to the analysis of space configuration....
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Discovering interactions between applications with log analysis
PublikacjaApplication logs record the behavior of a system during its runtime and their analysis can provide useful information. In this article, we propose a method of automated log analysis to discover interactions taking place between applications in an enterprise. We believe that such an automated approach can greatly support enterprise architects in building an up-to-date view of a governed system in a modern, fast-paced development...
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Numerical and Clinical Analysis of an Eyeball Injuries under Direc Impact
PublikacjaObjectives: The objective of this study was to develop a numerical model of the eyeball and orbit to simulate a blunt injury to the eyeball leading to its rupture, as well as to conduct a comparative analysis of the results obtained using the finite element method against the clinical material concerning patients who had suffered an eyeball rupture due to a blunt force trauma. Material and Methods: Using available sclera biometric and...
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The effect of numerical 2D and 3D FEM element modelling on strain and stress distributions at laser weld notches in steel sandwich type panels
PublikacjaLike other means of transport, merchant ships face the problem of increasing requirements concerning the environment protection, which, among other issues, implies the reduction of fuel consumption by the ship. Here, the conventional approach which consists in making use of higher strength steels to decrease the mass of the ship hull can be complemented by the use of new steel structures of sandwich panel type. However, the lack...
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Kinetic analysis of the stage for a high speed steam turbine
PublikacjaThis article analyzes possibilites of resonances within a control stage for a high speed steam turbine. This stage hase been based on assembling of a single blade to a rotating disk and increasing of rigidity of the system by using of a bandage. In the analysis will be nd a possiblity of resonance frequency, and mistuning by showing safety working ranges. The calculations have bean used the3D modal and harmonic analysis by the...
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Multidimensional GIS for satellite imagery analysis
PublikacjaMultidimensional Geographical Information System allows storing, querying and processing of multidimensional query data. It is able to process satellite imagery and provide tools for its analysis. In the article authors present the developed system that analyzes a time series of SENTINEL - 1 mission satellite imagery acquired over the coast of Poland. The algorithm used finds and detects changes in the shape...