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Search results for: COMPUTER AIDED DESIGN, FINITE ELEMENT METHOD (FEM), PARAMETERIZED MACROMODELS, REDUCED-ORDER MODEL, WAVEGUIDE FILTERS
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Design and implementation principles of FIReWORK ONLINE - the VHDL autogenerator for hardware structures
PublicationThe paper presents an aspects of remote autogeneration of hardware structures. The solution is an online application, that is running on the server side and allows to design a particular filters and other selected hardware and generate its structure in the form of VHDL, dedicated to FPGA design environments. The paper also addresses the problem of parameterization of algorithms used to generate the hardware structures and current...
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Design Space Reduction for Expedited Multi-Objective Design Optimization of Antennas in Highly-Dimensional Spaces
PublicationA surrogate-based technique for efficient multi-objective antenna optimization is discussed. Our approach exploits response surface approximation (RSA) model constructed from low-fidelity antenna model data (here, obtained through coarse-discretization electromagnetic simulations). The RSA model enables fast determination of the best available trade-offs between conflicting design goals. The cost of RSA model construction for multi-parameter...
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An application of multi-agent system for ship’s power systems design
PublicationDesign process of transport ship power system consists of structure (topology) and component elements selection. Compliance with the requirements for static components does not guarantee optimal dynamic characteristics of entire power system. Design steps are difficult to formalize and as a consequence to this reason expert and multi-agent systems are used for solving selected design issues. In the paper distributed multi-agent...
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Higher harmonics produced by traction substations – computer modelling and experimental verification
PublicationVoltage and current harmonics have a detrimental effect on the components of a power system. Current harmonics may result in the overload and damage to power transformers, although the rms value of load current does not exceed their current-carrying capacity. Voltage harmonics may result in, for example, damage to capacitor banks used to compensate reactive power. Devices which contribute to both current and voltage distortion...
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Application of auto calibration and linearization algorithms to improve sound quality of computer devices
PublicationAn application of auto calibration and linearization algorithms designed for correcting acoustic characteristics of selected computer devices was presented in the paper. The functionality of the algorithms were presented for two kind of computer devices: ultrabook class computer and portable device of All-In-One type. The algorithms were adjusted for the given type of the device on the basis of series of measurements conducted...
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Machine-aided detection of SARS-CoV-2 from complete blood count
PublicationThe current gold standard for SARS-CoV-2 detection methods lacks the functionality to perform population screening. Complete blood count (CBC) tests are a cost-effective way to reach a wide range of people – e.g. according to the data of the Central Statistical Office of Poland from 2016, there are 3,000 blood diagnostic laboratories in Poland, and 46% of Polish people have at least one CBC test per year. In our work, we show...
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Advanced fatigue and rutting characterisation of Polish asphalt mixtures based on the VECD model and viscoplastic shift model
PublicationThe advanced asphalt mixture performance-related specifications (AM-PRS) recently developed in USA can allow an optimisation of the design process of asphalt pavements thanks to the possibility to fully take into account the intrinsic material properties. In this study, four typical Polish mixtures, i.e. a Stone Mastic Asphalt (SMA) for wearing course, two mixtures for binder course with neat bitumen or Polymer modified Bitumen...
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Accurate simulation-driven modeling and design optimization of compact microwave structures
PublicationCost efficient design optimization of microwave structures requires availability of fast yet reliable replacement models so that multiple evaluations of the structure at hand can be executed in reasonable timeframe. Direct utilization of full-wave electromagnetic (EM) simulations is often prohibitive. On the other hand, accurate data-driven modeling normally requires a very large number of training points and it is virtually infeasible...
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Waveguide modeling as a tool for fitting a hearing aid
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Analysis of single-ground-plane coplanar waveguide
PublicationW pracy przedstawion metodę analizy rodziny koplanarnych linii transmisyjnych z pojedynczym przewodem masy. Oryginalne, nie znane wcześniej wyniki modelowania numerycznego potwierdzone zostały dużą zgodnością z wynikami pomiarów wykonanych dla struktury falowodu koplanarnego z pojedynczym przewodem masy (SGP-CPW.
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Characterization of rectangular waveguide with a pseudochiral omega slab
PublicationMetodę dopasowania rodzajów zastosowano do rozwiązania falowodu prostokątnego zawierającego materiał pseudochiralny typy Omega. Zdefiniowano własności rodzajów pola w badanej prowadnicy oraz zauważono wystąpienie efektu przemieszczenia pola. Określono pełnofalową macierz rozproszenia sekcji badanego falowodu oraz porównano wyniki symulacji charakterystyk transmisyjnych sekcji z eksperymentem. W oparciu o uzyskane wyniki dokonano...
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Ferrite posts in multi-port waveguide junctions
PublicationMetodę dopasowania rodzajów zastosowano do połączenia zastępczego pola rozproszonego od dowolnej konfiguracji jedno i dwuwarstwowych prętów ferrytowych i dielektrycznych z pobudzeniem z falowodu prostokątnego. Zaprezentowano częstotliwościowe charakterystyki macierzy rozproszenia dla rodzaju podstawowego. Zaobserwowano przełączające (czterowrotnik zawierający dwa pręty ferrytowe) własności badanych układów.
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Non-linear circuit model of a single doubly-fed induction machine formulated in natural axes for drive systems simulation purposes
PublicationMathematical modelling and a circuit model formulated in natural axes of a single doubly-fed induction machine, with the account of magnetic circuit nonlinearity are presented in the paper. Derivation of the model differential equations was based on Lagrange's energy method. State functions of magnetic elements in the model are non-linear and depend on all currents flowing in the machine windings and on the angle of rotor position....
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The finite-difference simulation of x-rays propagation through a system of lenses
PublicationThe propagation of X-ray waves through an optical system consisting of 33 aluminum X-ray refractive lenses is considered. For solving the problem, a finite-difference method is suggested and investigated. It is shown that very small steps of the difference grid are necessary for reliable computation of propagation of X-ray waves through the system of lenses. It is shown that the wave phase is a function very quickly increasing...
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Numerical Model of Femur Part
PublicationThe aim of the study is to create a new more accurate method of femur part modelling by using the finite element method. According to this new method, a femur part is treated as a complex structure composed of trabecular bone (internal part) and cortical bone (external part). The internal part is modelled as a scaffold, thus the external part is modelled as a coat (i.e. covering). Applying the programme ABAQUS, there were created...
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New synthesis route of highly porous InxCo4Sb12 with strongly reduced thermal conductivity
PublicationHighly porous, In-filled CoSb3 skutterudite materials with an attractive thermoelectric figure of merit (ZT * 1) and corresponding dense samples were fabricated through the cost-effective method of reduction in oxides in dry hydrogen and the pulsed electric current sintering (PECS) method, respectively. The reduction process was described in detail using in situ thermogravimetric analysis of Co2O3, Sb2O3 and In(NO3)35H2O separately...
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Application of a hybrid finite difference-mode matching method to the analysis of circular cavities loaded with cylindrical metallic objects
PublicationW artykule przedstawiono badania rezonatorów cylindrycznych zawierających obiekty cylindryczne o dowolnym przekroju poprzecznym z wykorzystaniem metody hybrydowej stanowiącej połączenie metody różnic skończonych z metodą dopasowania rodzajów. W ramach badań określono częstotliwości rezonansowe dla wybranych struktur rezonatorów. Wyniki numeryczne zostały zweryfikowane eksperymentalnie.
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Analysis of scattering from arbitrary configuration of cylindrical objects using hybrid finite-difference mode-matching method
PublicationW artykule przedstawiono nową metodę hybrydową stanowiącą połączenie metody różnic skończonych z metodą dopasowania rodzajów, pozwalającą na analizę obiektów cylindrycznych o dowolnym przekroju poprzecznym. W prezentowanej metodzie poszczególne obiekty reprezentowane są poprzez wielorodzajową macierz impednacyjną zdefiniowaną na powierzchni bocznej zastępczego cylindra zawierającego badany obiekt. Celem określenia parametrów rozproszenia...
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Hybrid finite-difference/mode-matching method for analysis of scattering from arbitrary configuration of rotationally-symmetrical posts
PublicationW artykule przedstawiona została metoda hybrydowa pozwalająca na analizę zjawiska rozpraszania od dowolnej konfiguracji obiektów o osiowej symetrii. Proponowana metoda oparta jest na reprezentacji obiektu lub dowolnej konfiguracji obiektów poprzez zastępczy obiekt kulisty ze znanymi warunkami brzegowymi. W analizie pojedynczego obiektu wykorzystana została metoda hybrydowa stanowiąca połączenie metody różnic skończonych z metodą...
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The use of a two-phase Monte Carlo material model to reflect the dispersion of asphalt concrete fracture parameters
PublicationThe work covers comprehensive laboratory tests of semi-circular bending (SCB) of asphalt concrete samples. The results of two test series, including four and 32 SCB specimens, indicate a substantial scatter of force–deflection (F-d) histories. The numerical analysis is aimed to reflect the maximum breaking load and fracture energy of the samples, pointing out their random character. The original simulation-based fictitious Monte...
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A Wideband Rotary-Joint-Free H-Plane Horn Antenna With 360° Steerable Radiation Pattern Using Gap Waveguide Technology
PublicationConsidering the limitations of electronically steerable antennas such as limited steering span, gain degradation for large steering angles, complexity, and cost, this article is focused on the design of a simple mechanically steerable H-plane horn antenna. It is shown that since there is no need for an electrical connection between the top and bottom sections of a gap waveguide (GWG), if a sectoral horn is properly designed and realized...
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Posttraumatic Orbital Emphysema: A Numerical Model
PublicationOrbital emphysema is a common symptom accompanying orbital fracture. The pathomechanism is still not recognized and the usually assumed cause, elevated pressure in the upper airways connected with sneezing or coughing, does not always contribute to the occurrence of this type of fracture. Observations based on the finite model (simulating blowout type fracture) of the deformations of the inferior orbital wall after a strike in...
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Noise performance of continuous-time active-RC filters.
PublicationW pracy przedstawiono metodę analizy właściwości szumowych filtrów aktywnych RC czasu ciągłego. Prezentowana procedura wykorzystuje model integratorowy, z odpowiednim dla tej klasy filtrów opisem macierzowym. Dokładność osiągniętych wyników teoretycznych dla przykładowego filtru potwierdzono rezultatami otrzymanymi przy pomocy symulatora SPICE.
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Computer-assisted pronunciation training—Speech synthesis is almost all you need
PublicationThe research community has long studied computer-assisted pronunciation training (CAPT) methods in non-native speech. Researchers focused on studying various model architectures, such as Bayesian networks and deep learning methods, as well as on the analysis of different representations of the speech signal. Despite significant progress in recent years, existing CAPT methods are not able to detect pronunciation errors with high...
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Estimation of structural stiffness with the use of Particle Swarm Optimization
PublicationThe paper presents the theoretical background and four applications examples of the new method for the estimation of support stiffness coefficients of complex structures modelled discretely (e.g. with the use of the Finite Element Model (FEM) method based on the modified Particle Swarm Optimization (PSO) algorithm. In real-life cases, exact values of the supports’ stiffness coefficients may change for various reasons...
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Port-based approach to distributed transfer function method
PublicationIn the paper there is presented an uniform, port-based approach to modeling of both lumped and distributed parameter systems. Port-based model of distributed system has been defined by application of distributed transfer function method (DTFM). The approach proposed combines versatility of port - based modeling and accuracy of distributed transfer function method. It enables to formulate appropriate input data for computer analysis...
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Simulation of static response of thin walled bars with changed design parameters by means of second order sensitivity analysis.
PublicationZa pomocą analizy wrażliwości drugiego rzędu wyznaczono przybliżone wartości sił wewnętrznych i przemieszczeń pręta cienkościennego dla zmieniających się parametrów projektowych. W przykładzie numerycznym wyznaczono pierwszą i drugą wariację bimomentu w funkcji grubości półek skręcanego dwuteownika. Zbadano dokładność rozwiązania uzyskanego za pomocą analizy wrażliwości z rozwiązaniem ścisłym.
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Investigation of the Efficiency of a Dual-Fuel Gas Turbine Combustion Chamber with a Plasma‒Chemical Element
PublicationThe study is devoted to the possibility of increasing the efficiency of the working process in dual-fuel combustion chambers of gas turbine engines for FPSO vessels. For the first time, it is proposed to use the advantages of plasma‒chemical intensification of the combustion of hydrocarbon fuels in the dual-fuel combustion chambers, which can simultaneously operate on gaseous and liquid fuels. A design scheme of a combustion chamber...
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MULTI-CRITERIA INVESTMENT DECISION SUPPORT MODEL USING FUZZY ANALYTIC HIERARCHY PROCESS (F-AHP) METHOD FOR POWER INDUSTRY
PublicationIn this paper, the comparative analysis of two wind farm construction projects was presented. This particular type of analysis is commonly applied before purchasing investment project being in a planning phase by a company interested in its development. Conduction of this type of analysis is prompted by the necessity to take into consideration the requirements of Polish legislation. Comparison of wind farm construction projects...
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Reinforcement Learning Algorithm and FDTD-based Simulation Applied to Schroeder Diffuser Design Optimization
PublicationThe aim of this paper is to propose a novel approach to the algorithmic design of Schroeder acoustic diffusers employing a deep learning optimization algorithm and a fitness function based on a computer simulation of the propagation of acoustic waves. The deep learning method employed for the research is a deep policy gradient algorithm. It is used as a tool for carrying out a sequential optimization process the goal of which is...
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Computer-assisted assessment of learning outcomes in the laboratory of metrology
PublicationIn the paper, didactic experience with broad and rapid continuous assessment of students’ knowledge, skills and competencies in the Laboratory of Metrology, which is an example of utilisation of assessment for learning, is presented. A learning management system was designed for manage, tracking, reporting of learning program and assessing learning outcomes. It has ability to provide with immediate feedback, which is used by the...
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Design and Synthesis of NTU-9/C3N4 Photocatalysts: Effects of NTU-9 Content and Composite Preparation Method
PublicationHybrid materials based on graphitic carbon nitride (g-C3N4) and NTU-9 metal–organic frameworks (MOF) were designed and prepared via solvothermal synthesis and calcination in air. The as-prepared photocatalysts were subsequently characterized using Brunauer–Emmett–Teller (BET) analysis, UV-Vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) emission spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy...
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Quasi-solutions for generalized second order differential equations with deviating arguments
PublicationThis paper deal with boundary value problems for generalized second order differential equations with deviating arguments. Existence of quasi-solutions and solutions are proved by monotone iterative method. Examples with numerical results are added.
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Exactly solvable model of two trapped quantum particles interacting via finite-range soft-core interactions
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On possible applications of media described by fractional-order models in electromagnetic cloaking
PublicationThe purpose of this paper is to open a scientific discussion on possible applications of media described by fractional-order (FO) models (FOMs) in electromagnetic cloaking. A 2-D cloak based on active sources and the surface equivalence theorem is simulated. It employs a medium described by FOM in communication with sources cancelling the scattered field. A perfect electromagnetic active cloak is thereby demonstrated with the use...
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Inverse Nonlinear Eigenvalue Problem Framework for the Synthesis of Coupled-Resonator Filters With Nonresonant Nodes and Arbitrary Frequency-Variant Reactive Couplings
PublicationA novel, general circuit-level description of coupledresonator microwave filters is introduced in this article. Unlike well-established coupling-matrix models based on frequency-invariant couplings or linear frequency-variant couplings (LFVCs), a model with arbitrary reactive frequencyvariant coupling (AFVC) networks is proposed. The engineered formulation is more general than prior-art ones—with the only restriction that the coupling...
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Mathematical modelling and computer simulation of activated sludge systems.Second edition
PublicationMathematical Modelling and Computer Simulation of Activated Sludge Systems – Second Edition, provides, from the process engineering perspective, a comprehensive and up-to-date overview regarding various aspects of the mechanistic (“white box”) modelling and simulation of advanced activated sludge systems performing biological nutrient removal. In the new edition of the book, a special focus is given to nitrogen removal and an overview...
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Multimodal human-computer interfaces based on advanced video and audio analysis
PublicationMultimodal interfaces development history is reviewed briefly in the introduction. Some applications of multimodal interfaces to education software for disabled people are presented. One of them, the LipMouse is a novel, vision-based human-computer interface that tracks user’s lip movements and detect lips gestures. A new approach to diagnosing Parkinson’s disease is also shown. The progression of the disease can be measured employing...
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THE USE OF FEM FOR DETERMINATION OF RESONANT FREQUENCIES OF CIRCULAR SAW BLADES WITH INDIRECT TEETH IN GULLETS
PublicationUnderstanding the dynamical properties of the circular saw blade is necessary, since, there is a really need for a stable work at working rotational speeds, which are determined by frequencies at which the circular saw blade tends to vibrate. It was observed that the resonant frequency depend on the circular saw blade shape, a collar diameter and on saw’s teeth shape. In the presented work an attention was paid to the effect of...
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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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COMPUTER ANALYSIS OF HYDRAULIC CONDITIONS IN A SANITARY CHAMBER
PublicationThis paper presents analysis of hydraulic conditions of sewage flow down the slipway (ramp) in the collecting sanitary chamber connecting 3 collectors on the inlet: ⌀600, ⌀800 and ⌀1400 and one on the outlet ⌀1600 mm, with a maximum difference of elevation 5 m. The mathematical model has been made and hydraulic calculations were carried out in steady flow conditions. Then wastewater surface elevation, energy grade line elevation,...
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Methodology of Affective Intervention Design for Intelligent Systems
PublicationThis paper concerns how intelligent systems should be designed to make adequate, valuable and natural affective interventions. The article proposes a process for choosing an affective intervention model for an intelligent system. The process consists of 10 activities that allow for step-by-step design of an affective feedback loop and takes into account the following factors: expected and desired emotional states, characteristics...
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Performance optimization of continuous-time OTA-C filters.
PublicationW pracy przedstawiono analityczne podejśćie do optymalizacji właściwości filtrów OTA-C czasu ciągłego. Zaprezentowano efektywne metody analizy zniekształceń nieliniowych i szumów dla dowolnego filtru OTA-C wykorzystując ogólny model oparty na opisie macierzowym. Rezultaty teoretyczne odnoszące się do kaskadowego filtru typu Butterwotha były weryfikowane na drodze porównawczej z wynikami otrzymanymi na poziomie ''Transistor-Level''...
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THE METHOD OF MEASURING THE MEMBRANE COVER GEOMETRY USING LASER SCANNING AND SYNCHRONOUS PHOTOGRAMMETRY
PublicationThe authors present the experience and results of field studies carried out at the technical acceptance of Forest Opera (name in Polish: Opera Leśna) in Sopot (Poland). An unusual design of covering made in the form of “Sheerfill I” technical fabric membrane required spanned in the form of sails, required the use of terrestrial laser scanning. Such approach allowed for the fast and accurate record of the surface of individual panels...
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Human-Computer Interface Based on Visual Lip Movement and Gesture Recognition
PublicationThe multimodal human-computer interface (HCI) called LipMouse is presented, allowing a user to work on a computer using movements and gestures made with his/her mouth only. Algorithms for lip movement tracking and lip gesture recognition are presented in details. User face images are captured with a standard webcam. Face detection is based on a cascade of boosted classifiers using Haar-like features. A mouth region is located in...
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STEADY STATE VISUALLY EVOKED POTENTIALS FOR BRAIN COMPUTER INTERFACE
PublicationAn experiment conducted to validate a possibility of use a single active electrode EEG device for detecting Steady State Visually Evoked Potentials (SSVEP) is shown. A LED stimulator was applied to stimulate patients with two different frequencies - 13 Hz and 17 Hz. First, EEG signals were recorded and pre-processed using MATLAB software. In the next step recordings were analysed and classified employing the WEKA software. As indicated...
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PUBLIC SOURCES OF FINANCE FOR CULTURE AS AN ELEMENT OF CULTURAL SECURITY IN POLAND
PublicationCulture is an important element of the country, playing an important role both for its security and the economy. It cannot be only seen as a cost-creating sector, but may be a significant factor in economic development. For this to happen, it is necessary to create a system of financing this economic sector. This article’s aim is to analyze the use of funds from public sources in Poland to finance culture-related activities. The...
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MHD darcy-forchheimer nanofluid flow and entropy optimization in an odd-shaped enclosure filled with a (MWCNT-Fe3O4/water) using galerkin finite element analysis
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Development of Technical Creativity Featuring Modified TRIZ-AM Inventive Principle to Support Design for Additive Manufacturing
Publicationhe design for additive manufacturing (DFAM) processing was introduced to fully utilise the design freedom provided by additive manufacturing (AM). Consequently, appropriate design methodologies have become essential for this technology. Recently, many studies have identified the importance of DFAM method utilisation to produce AM parts, and TRIZ is a strategy used to formalise design methodologies....
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Simulation of fluid structure interaction in a novel design of high pressure axial piston pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...