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Wyniki wyszukiwania dla: melting point calculation
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Fixed point indices of iterated smooth maps in arbitrary dimension
PublikacjaWe give a complete description of possible sequences ofindices of iterations of f at an isolated fixed point, answering inaffirmative the Chow, Mallet-Paret and Yorke conjecture posed in[S.N. Chow, J. Mallet-Parret, J.A. Yorke, A periodic point index whichis a bifurcation invariant, in: Geometric Dynamics, Rio de Janeiro,1981, in: Lecture Notes in Math., vol. 1007, Springer, Berlin, 1983,pp. 109-131].
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N-point estimators of the Instantaneous Complex Frequency
PublikacjaIn this paper estimators of the instantaneous complex frequency (ICF) are presented and discussed. The differential approach for the estimation of the ICF is used, therefore the estimators are based on maximally flat N-point FIR filters: differential and delay. The investigation of the filter performance includes static characteristics of ICF estimation and the error of the ICF estimation in the discrete frequency domain.W pracy...
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Computational methods for calculation of binding free energy for ligand-receptor complexes
PublikacjaAccurate description of the molecular complexes energetic influence is required for understanding of many biological functions carried out by proteins. Therefore, estimation of binding free energy for ligand-receptor complexes is of highest importance for structure-based ligand design and drug discovery approaches.Experimental methods of determination of difference in Gibbs'es free energy have many limitations. Thus, computational...
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Improvement of Thrust Bearing Calculation Considering the Convectional Heating within the Space between the Pads
PublikacjaA modern thrust bearing tool is used to estimate the behavior of tilting pad thrust bearings not only in the oil film between pad and rotating collar, but also in the space between the pads. The oil flow in the space significantly influences the oil film inlet temperature and the heating of pad and collar. For that reason, it is necessary to define an oil mixing model for the space between the pads. In the bearing tool, the solutions...
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An Optimal Power Point Tracking Algorithm in a Solar PV Generation System
PublikacjaThe non-linearity in I-V characteristics of a PV panel requires to be operated at knee point to extract maximum power. In order to operate the panel at optimal point, maximum power point tracking (MPPT) algorithm is employed in the control structure. The main objective of MPP tracking is to keep the operation at knee point of I-V characteristics under varying condition of temperature and solar insolation. Under non uniform solar...
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Phase Transitions in Pores: Experimental and Simulation Studies of Melting and Freezing
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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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A Finer Point on Vision
PublikacjaAs an IES Member, I look forward to each issue of LD+A and read them with great interest as they are often very informative. To my surprise, the Research article (May 2019, p. 76) has an error which should be corrected.
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Reconstruction Methods for 3D Underwater Objects Using Point Cloud Data
PublikacjaExisting methods for visualizing underwater objects in three dimensions are usually based on displaying the imaged objects either as unorganised point sets or in the form of edges connecting the points in a trivial way. To allow the researcher to recognise more details and characteristic features of an investigated object, the visualization quality may be improved by transforming the unordered point clouds into higher order structures....
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COMPARATIVE ANALYSIS OF POINT CLOUDS OBTAINED BY TLS AND PHOTOGRAMMETRY
PublikacjaTechnical progress in the field of 3D modelling resulted in increasing use of such technics to create a virtual 3D models of objects. Three-dimensional spatial models are used in a wide range of applications such as inventorisation of architectural-construction, an inventorisation of archaeological sites, medicine and wide-known engineering. Spatial models are created based on the point clouds acquired with laser scanners or photogrammetry....
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Microscopic calculation of the energetics of ions in polyethylene
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A new viscoelastic method of calculation of low-temperature thermal stresses in asphalt layers of pavements
PublikacjaThe paper presents a new method of calculation of thermal stresses in asphalt layers of pavements induced by cooling or heating. The method, developed by the author, is based on the analytical solution for the linear viscoelastic Burgers model extended numerically for the case of asphalt layers whose rheological parameters are strongly dependent on temperature. The coefficient of thermal expansion and Poisson’s ratio may optionally...
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Modeling BIM Objects From Point Clouds. Examples
PublikacjaThe article presents several ways to obtain BIM (Building Information Modeling) models from point clouds using standard commands in Revit 2018. In Revit geometric forms are possible to obtain in project, family or conceptual environments. Efficient modeling requires knowledge of methods of creating families and components in these environments and ways to combine them. Modeling methods with system and loadable families are presented,...
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Positron-electron correlation-polarization potentials for the calculation of positron collisions with atoms and molecules
PublikacjaWe present correlation-polarization potentials for the calculation of scattering cross sections of positrons with atoms and molecules. The potentials are constructed from a short-range correlation term and a long-range polarization term. For the short-range correlation term we present four different potentials that are derived from multi-component density functionals. For the long-range polarization term we employ a multi-term...
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FEM simulation of laminate failure in the three point bending
PublikacjaThe paper presents a FEM simulation of failure of laminate subjected to the three point bending. The numeri-cal model is based on the equivalent single layer approach with 6-paramater non-linear shell theory kinematics. It is implemented in the non-commercial FEM code. The failure initiation is detected with the use of Tsai-Wu criterion. After the failure onset the progressive failure process is modelled through the appropriate...
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Service time distribution influence on end-to-end call setup delay calculation in networks with Session Initiation Protocol
PublikacjaThe most important GoS parameter for networks with SIP protocol is end-to-end call setup delay. So far there were no coherent models allowing calculation of these parameters for networks with SIP protocol. Few models were developed but they are insufficient. In the paper we propose model which allows end-to-end call setup delay calculation for networks with SIP protocol. The model is using chain of M/G/1/K models and is applicable...
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3D POINT-CLOUD SPATIAL EXPANSION BY TOTAL LEAST-SQUARES LINE FITTING
PublikacjaPoint-cloud spatial expansion (PCSE) allows the creation of a new pointcloud form that presents an alternative geometry of an entire object in a single spatial view. Spatial expansion facilitates the analysis process and introduces an additional spatial parameter describing the point cloud. An important element of the PCSE method is determining the position of the axis of symmetry of a symmetrical object: the procedure for determining...
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Interior Point Method Evaluation for Reactive Power Flow Optimization in the Power System
PublikacjaThe paper verifies the performance of an interior point method in reactive power flow optimization in the power system. The study was conducted on a 28 node CIGRE system, using the interior point method optimization procedures implemented in Power Factory software.
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A Conception of Pairwise Comparisons Model for Selection of Appropriate Body Surface Area Calculation Formula
PublikacjaBody surface area (BSA) may be computed using a variety of formulas, but the computed BSA differs from real BSA values for particular subjects. This is presented in the paper by computing BSA values for selected subject and comparing them to the real BSA value obtained with the use of a 3D body scanner. The results show inequalities in the relevant BSA computing formulas. Hence, there is a need to determine a method that will allow...
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Computer-aided design and selective laser melting of porous biomimetic materials
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Multiaxial fatigue behaviour of maraging steel produced by selective laser melting
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Melting and crystallization DSC profiles of milk fat depending on selected factors
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The structure and melting of lead nanocrystalline layer in reduced lead-germanate glass
PublikacjaNanokrystaliczna warstwa granul Pb na powierzchni szkieł ołowiowo-germanianowych została wytworzona poprzez wygrzewanie w wysokich temperaturach, w atmosferze wodoru. Właściwości tej warstwy silnie zależą od temperatury i czasu redukcji. Artykuł prezentuje rentgenowskie i mikroskopowe badania struktury warstwy oraz wpływ topnienia i krzepnięcia granul Pb na jej przewodnictwo.
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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) that can determine the probabilistic moments for engineering structures. The method is reasonably robust and adequately accurate for a wide range of practical problems. It is a special case of numerical quadrature based on orthogonal polynomials. The main advantage of this method is that, unlike FORM or SORM, it is not necessary to carry...
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Influence of Asphalt Binder on the Compactability of Asphalt Mixtures Using Locking Point
PublikacjaCompaction is an important process for the asphalt mixture service life. A properly compacted mixture is crucial for long-lasting pavement. The objective of this study was to evaluate the influence of asphalt binders on the compactability of the asphalt mixtures by utilizing the concept of the locking point. To achieve this objective, two compaction methods (impact and gyration), different temperatures and asphalt content, and...
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Comparison of 3D Point Cloud Completion Networks for High Altitude Lidar Scans of Buildings
PublikacjaHigh altitude lidar scans allow for rapid acquisition of big spatial data representing entire city blocks. Unfortunately, the raw point clouds acquired by this method are largely incomplete due to object occlusions and restrictions in scanning angles and sensor resolution, which can negatively affect the obtained results. In recent years, many new solutions for 3D point cloud completion have been created and tested on various objects;...
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Numerical solution of fractional neutron point kinetics in nuclear reactor
PublikacjaThis paper presents results concerning solutions of the fractional neutron point kinetics model for a nuclear reactor. Proposed model consists of a bilinear system of fractional and ordinary differential equations. Three methods to solve the model are presented and compared. The first one entails application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. Second involves building an analog scheme...
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Microscopic calculation of the static electric susceptibility of polyethylene
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Calculation of vibrational spectra for cyanobiphenyl liquid crystals
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Barkhausen Noise Calculation by Hysteresis Model Parameters
PublikacjaPętla histerezy natężenia efektu Barkhausena wyliczono wykorzystując model histerezowy. Założono, iż straty energii na efekt Barkhausena zależą od szybkości granicy domenowej oraz od częstości występowania skoków Barkhausena. Pokazano wyliczenia wykonane dla stali Fe-Si (ziarna zorientowane w kierunku [100] względem kierunku walcowania)
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On numerical calculation of acoustic field of plane source.
PublikacjaSkładowe harmoniczne wiązki akustycznej zostały obliczone na podstawie reprezentacji w postaci całek według teorii reprezentacji. Zastosowano nowe metody do obliczania całek od funkcji szybko oscylacyjnych.
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Adapting the pinch point analysis to improve the ORC design process
PublikacjaPinch point analysis can be adapted so as to assist in the early stages of designing the ORC systems. Typically used in determining the working parameters of heat exchangers, it can be employed to improve the heat fitting between the source of heat and the working fluids of the ORC system. To attain the parametric match, an algorithm was built enabling quick estimation of the possible heat reception by the specific working fluid....
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Laboratoryjny przetwornik a/c typu "floating-point" na bazie karty DAQ
PublikacjaW artykule przedstawiono zrealizowany przetwornik a/c typu "floating-point" na bazie karty akwizycji danych typu PCI-6221 uzupełnionej o wzmacniacz wejściowy o programowanym wzmocnieniu. Opisywany przetwornik jest podstawą ćwiczenia w laboratorium studenckim. W skład ćwiczenia wchodzą dodatkowo program symulacyjny pozwalający zapoznać się z ideą pracy przetworników typu "floating-point", a następnie przejść do realizacji przetwornika...
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Calculation of Induced Sheath Voltages in Power Cables – Single Circuit System versus Double Circuit System
PublikacjaThis paper presents comparison of values of induced sheath voltages in power cable metallic sheaths when one or two cables per phase are used. Calculation of voltages is performed for various phase sequences of the power cables. Three types of the sheaths bonding and earthing are considered. Shock hazard and voltage stress of non-metallic outer sheath of cables are evaluated. The proposed, optimal configuration of the power cable...
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STANY NIEUSTALONE TOWARZYSZĄCE POMIAROWI IMPEDANCJI PĘTLI ZWARCIA W OBWODACH WYJŚCIOWYCH ZASILACZY BEZPRZERWOWYCH UPS
PublikacjaW pracy przedstawiono metodykę i wyniki pomiarów stanów nieustalonych w zasilaczu bezprzerwowym (UPS) typu on - line. Do rejestracji zdarzeń po stronie zasilania i na wyjściu UPS wykorzystano dwa przyrządy do pomiaru jakości energii elektrycznej zsynchronizowane czasowo. Rejestratory kompresują uzyskane dane pomiarowe, co może wprowadzać dodatkowe błędy pomiaru wielkości mierzonych – napięć i prądów. Dodatkowe rejestracje oscyloskopem...
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Multi-nodal PWR reactor model — Methodology proposition for power distribution coefficients calculation
PublikacjaIn the paper the multi-nodal Pressurized Water Reactor (PWR) model called Mann’s model is presented. This models is used for modelling purposes of the heat transfer from fuel to coolant in reactor core. The authors expand widely used in literature approach by defining additional coefficients for the heat transfer model. These parameters approximate the power generation distribution in the PWR reactor core according to the to the...
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Hybrid Finite Element Method Development for Offshore Structures’ Calculation with the Implementation of Industry Standards
PublikacjaIn the design process of offshore steel structures, it is typical to employ commercial calculation codes in which simulation and evaluation of results are performed on the basis of the available standards (e.g. API, DNV, Lloyds). The modeling and solution rely on finite element methods and cover the simulation of the structure’s properties along with the influence of the marine environment – sea currents, wave and wind loading,...
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4-Point beam tensile test on a soft adhesive
PublikacjaAn adhesive butt joint with a soft bondline has been studied. A series of experiments was conducted on test pieces constituted of aluminium adherends bonded with a low modulus epoxy adhesive, ScotchWeld™ 2216. The joint was subjected to four point bending, in tension/compression loading, under constant deflection rate, with the bondline being parallel to the applied load. The objective was to examine and evaluate crack nucleation...
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Model of heat transfer in the stagnation point of rapidly evaporating microjet
PublikacjaThe paper presents investigation into the single water microjet surface cooling producing evaporating film. Reported tests were conducted under steady state conditions. Experiments were conducted using the nozzle size of 70 and 100 mikrometer respectively. In the course of investigations obtained were experimental relations between heat flux and wall superheating. It was proved that the phenomenon is similar to that of pool boiling...
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Size-exclusion chromatography for the determination of the boiling point distribution of high-boiling petroleum fractions
PublikacjaThe paper describes a new procedure for the determination of boiling point distribution of high-boiling petroleum fractions using size exclusion chromatography with refractive index detector. Thus far, the determination of boiling range distribution by chromatography has been accomplished using simulated distillation with gas chromatography with the flame ionization detection. This study revealed that in spite of substantial differences...
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Hybrid Finite Element Method Development for Offshore Structures’ Calculation with the Implementation of Industry Standards
PublikacjaIn the design process of offshore steel structures, it is typical to employ commercial calculation codes in which simulationand evaluation of results are performed on the basis of the available standards (e.g. API, DNV, Lloyds). The modelingand solution rely on finite element methods and cover the simulation of the structure’s properties along with the influenceof the marine environment – sea currents, wave...
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Postquarter-Point Case of Ship’s Side-Berthing and Its Influence on Marine Fender Pitch
PublikacjaThis paper presents a critical analysis of some selected codes and practical recommendations used as basic rules in the design procedures of modern marine fender systems. The first part of the discussion pertains to the existing equations used in calculating the eccentricity coefficient in the ship’s kinetic energy equation and the maximum allowable fender pitch (spacing) in a set of fenders installed along a quay wall. A new approach...
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From a Point Cloud to a 3D Model - an Exercise for Users of AutoCAD and Revit
PublikacjaThe paper presents a proposal of the topic of an exercise for students of building faculties as part of classes on 3D modelling. The task consists in creating a three-dimensional model based on the measurement obtained with the Leica P30 laser scanner. Due to the maximum number of points in the cloud in the presented programs, the output files must be properly cleared and reduced. The point cloud was pre-processed in Cyclone software....
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Structural studies and melting of bismuth nanocrystals in reduced bismuthgermanate and bismuth silicate glasses.
PublikacjaOtrzymano nanostruktury krystalicznego bizmutu w matrycy XO2 (X=Si,Ge) oraz warstwę nanostruktur krystalicznego bizmutu na powierzchni redukowanych w atmosferze wodoru szkieł Bi0.33Ge0.67O1.84 i Bi0.57Si0.43O1.72. Kompozyt Bi-szkło badano metodą DSC, XRD oraz AFM. Zaobserwowano zmniejszenie temperatury topnienia nanokrystalicznego bizmutu znajdującego się w matrycy szkła z 544 K do 387 K oraz do 502 K w przypadku powierzchniowej...
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Methods for quality improvement of multibeam and LiDAR point cloud data in the context of 3D surface reconstruction
PublikacjaPoint cloud dataset is the transitional data model used in several marine and land remote-sensing applications. During further steps of processing, the transformation of point cloud spatial data to more complex models containing higher order geometric structures like edges and facets may be possible, if an appropriate quality level of input data is provided. Point cloud datasets usually contain a considerable amount of undesirable...
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Protection of Earthing Reactor Connected to the Star Point of a High Voltage Shunt Reactor
PublikacjaThe article presents the problem of protection of earthing reactors connected to the star point of shunt reactors in high voltage lines, with particular regard to the detection of internal faults. Model analyses for an actual system commissioned in 2015, which is intended to be provided with earthing reactors, are included.
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Processing of LiDAR and Multibeam Sonar Point Cloud Data for 3D Surface and Object Shape Reconstruction
PublikacjaUnorganised point cloud dataset, as a transitional data model in several applications, usually contains a considerable amount of undesirable irregularities, such as strong variability of local point density, missing data, overlapping points and noise caused by scattering characteristics of the environment. For these reasons, further processing of such data, e.g. for construction of higher order geometric models of the topography...
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A new duty cycles calculation method in pulse width modulation for direct matrix converters based on the shape function concept
PublikacjaPaper presents a new approach to duty cycle calculation in pulse width modulation for direct matrix converters. The essence of the proposed method is the use of elementary shape function of finite element. The algorithm for calculating the duty cycles was reduced to simple operations on the coordinates of input and output voltage vectors without trigonometric functions.
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Fractional neutron point kinetics equations for nuclear reactor dynamics – Numerical solution investigations
PublikacjaThis paper presents results concerning numerical solutions to a fractional neutron point kinetics model for a nuclear reactor. The paper discusses and expands on results presented in (Espinosa-Paredes et al., 2011). The fractional neutron point kinetics model with six groups of delayed neutron precursors was developed and a numerical solution using the Edwards’ method was proposed (Edwards et al., 2002). The mathematical model...
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Assessing historical church tower asymmetry using point cloud spatial expansion
PublikacjaChurch towers are key cultural heritage. In theory, towers are vertical, while facade elements are symmetrically positioned around the tower axis. However, during service of a structure, building and lifetime conditions cause deviations, with associated risks. Laser scanning point clouds can be used to assess the structural state but a universal approach was missing. The proposed algorithm first estimates the tower inclination,...