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Search results for: DYNAMIC MECHANICAL PROPERTIES
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Influence of friction stir welding technological parameters on the properties of the joints of selected aluminum alloys
PublicationThe purpose of this dissertation was to determine the effect of friction stir welding technological parameters on the properties of selected aluminum alloy joints, with consideration of the residual stresses and dislocation density in the joints. The goal of the present work was also to produce defect-free joints with high mechanical and electrochemical properties. In the dissertation, similar welds of AA6082 alloy and dissimilar...
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Dynamic Nanoimpedance Characterization of the Atomic Force Microscope Tip-Surface Contact
PublicationNanoimpedance measurements, using the dynamic impedance spectroscopy technique, were carried out during loading and unloading force of a probe on three kinds of materials of different resistivity. These materials were: gold, boron-doped diamond, and AISI 304 stainless steel. Changes of impedance spectra versus applied force were registered and differences in the tip-to-sample contact character on each material were revealed. To...
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Application of galvanodynamic impedance spectroscopy for studying passive film cracking under mechanical strain
PublicationThe paper reports the results of simultaneous mechanical and electrochemical investigations on austenitic (18/8) stainless steel in a 2 % solution of sulphuric acid. The measurements were performed using Galvanodynamic Electrochemical Impedance Spectroscopy (GDEIS). Electrochemical analysis of mechanical passive layer cracking and repassivation conditions during a tensile test was carried out. Application of this methodology allowed...
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Segmentation concept in mechanical engineering
PublicationZaprezentowano nowoczesne podejście do rozwiązywania problemów technicznych, technologicznych i organizacyjnych przedsiębiorstwa w oparciu ich strukturyzację. Przedstawiono przykłady segmentcji w stosunku do przedmiotów obrabianych oraz struktur organizacyjnych przedsiębiorstwa.
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Functional properties of packaging materials from chemical modified stach.
PublicationThis work is focused on study of the mechanical and barrier properties of films obtained from potato starch modified with sodium tetrahydroxozincate generated in situ. The results show that the chemical modification of starch improved the water vapor permeability by about 25%, unfortunately decreased the elongation at break by 60%, when compared with unmodified starch films. However, placitization of films with glycerol at a concentration...
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Numerical Evaluation of Dynamic Response of a Steel Structure Model under Various Seismic Excitations
PublicationThe present paper reports the results of the study, which was designed to perform a numerical evaluation of dynamic response of a single-storey steel structure model. The experimental model was previously subjected to a number of different earthquake ground motions during an extensive shaking table investigation. The analyzed structure model was considered as a 1-DOF system with lumped parameters, which were determined by conducting...
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Mechanical and structural behavior of high-strength low-alloy steel pad welded by underwater wet welding conditions
PublicationThe aim of the paper was to determine the metallurgical and mechanical behaviors of a high-strength low-alloy (HSLA) steel pad-welded specimen used in the structures of industrial and naval parts. Then to predict the metallurgical consequences (nature of the phases present) and the mechanical properties (hardness and impact strength) of the pad-welded steel obtained by underwater wet welding with different heat input values. The...
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Active Dynamic Thermography imaging of wound healing processes in cardio surgery
PublicationThe surgery is a branch of medicine, that is integrally connected to wounds. Despite using sterile tools and compliance with aseptic rolls, some of the surgery wounds become infected. In clinical practice there is a lack of cheap, objective methods and tools for quantitative definition and estimation of the surgery wound healing progress. This paper presents preliminary results of Active Dynamic Thermography (ADT) parametric imaging...
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Comparison of perforator location in dynamic and static thermographic imaging with Doppler ultrasound in breast reconstruction surgery
PublicationThis paper co mpares the effectiveness of the dTnorm and t90_10 parametrizations in dynamic thermography for imaging location of perforators in TRAM flaps in the intraoperative period. The results were compared with the location detected in a Doppler ultrasound examination. Cold and heat stimulation was used in dynamic thermography. Additionally, these results were compared with static...
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Monitoring of crosslinking of a DGEBA-PAMAM adhesive in composite/aluminium bonded joint using mechanical and ultra-sound techniques
PublicationAdhesive cure is an important and determining aspect of strength and stability of bonded structures. Crosslinking of the polymer leads to the adhesive strength, stiffness and durability. Depending on the resin and curing agent used, cure time can vary from minutes to weeks, even then 100% crosslinking not being guaranteed. Standard methods based on dynamic mechanical analysis (DMA) or calorimetric techniques (DSC, DTA) are valuable...
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Timber-frame house resistant to dynamic loads - analysis of wall panel filled with polyurethane foam
PublicationThe present study shows the experimentally and numerically determined response of a single timber-frame house wall panel filled with polyurethane (PU) foam under dynamic loads. The harmonic tests were conducted for the following frequencies: 0.5 Hz, 1.0 Hz, 2.0 Hz and 5.0 Hz for various values of the specified displacement. Based on the results of the comparison between the experimental tests and the numerical analyses, the numerical...
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Influence of the Square Wave Voltage on Dynamical Properties of a Flat Voltammetric Electrode in the Time Domain by the Electrochemical Reversible Reaction
PublicationIn this article there is a presentation of the analysis of the polarizing voltage shape influencing dynamic properties of voltammetric electrodes when on their surface reversible reaction takes place in the time domain. The electrode polarization with linearly increasing voltage and with a square component, was analyzed. The analysis that were conducted showed that the voltammetric electrode behaves like a first order transducer....
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Local electrochemical impedance spectroscopy in dynamic mode of galvanic coupling
PublicationA novel method that combines local electrochemical impedance spectroscopy and mapping in dynamicmode is proposed. Method was validated over two galvanic couplings, namely zinc/copper and cad-mium/copper. Impedance spectrum response for all measuring points was obtained by means ofsimultaneous implementation of selected range of frequencies. Proposed method allows the measure-ment in a more time-efficient manner, at the same time...
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Export diversification and economic development: A dynamic spatial data analysis
PublicationThis paper contributes to the empirical literature on the relationship between “export variety” (export diversification) and economic development by relaxing the assumption of cross-country independence and allowing for spatial diffusion of shocks in observed and unobserved factors. Export variety is measured for a balanced panel of 114 countries (1992–2012) using very detailed information on their exports (HS 6-digit product level)....
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Tyre dynamic radius determination
PublicationW artykule opisano stanowisko wykorzystywane do badania oporu toczenia opon samochodowych znajdujące się w Katedrze Konstrukcji Maszyn i Pojazdów Wydziału Mechanicznego Politechniki Gdańskiej. Przedstawiono wyniki badań promienia dynamicznego opony Michelin 165/80R13 83T z bieżnikiem CLASSIC przeprowadzone z wykorzystaniem tego stanowiska na nawierzchni Safety Walk 80. Badania przeprowadzono zmieniając: prędkość jazdy, obciążenie...
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Active dynamic thermography in cardiosurgery
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On dynamic equations with deviating arguments
PublicationPraca dotyczy istnienia rozwiązań równań dynamicznych z odchylonymi argumentami. Podane zostały warunki dostateczne na istnienie rozwiązania. Dwa przykłady ilustrują otrzymane wyniki.
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Dynamic characteristics of interaperitoneal perfusion.
PublicationPrzedstawiono wyniki badań laboratoryjnych perfuzyjnego przepływu przez model jamy brzusznej człowieka. Szczególną uwagę zwrócono na techniczne aspekty modelu oraz wyników badań. Omówiono technikę pomiarową oraz przeanalizowano rezultaty pod kątem teorii przepływów przez zbiorniki i reaktory.
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Active dynamic thermography in mammography.
PublicationW artykule przedstawiono zaproponowany numeryczny model termiczny piersi z nowotworem umiejscowionym na różnych głębokościach. Przedstawione są wyniki symulacji modelu dla różnych warunków zewnętrznego pobudzenia termicznego powierzchni piersi. Pokazano również wyniki przykładowego badania termograficznego piersi z nowotworem.
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Dynamic thermography in diagnostics of onychomycosis.
PublicationW pracy zaprezentowano wyniki badań grzybicy paznokci przy użyciu termografii dynamicznej. Przedstawione wyniki badań pokazują, że metoda ta może okazać się skuteczna przy określaniu stanu mikrokrążenia w tkance pod paznokciem, co pozwoliłoby określić stopień zaawansowania choroby grzybiczej, a więc także umożliwiałoby ocenę postępów leczenia tej przypadłości.
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Nonlocalized thermal behavior of rotating micromachined beams under dynamic and thermodynamic loads
PublicationRotating micromachined beams are one of the most practical devices with several applications from power generation to aerospace industries. Moreover, recent advances in micromachining technology have led to huge interests in fabricating miniature turbines, gyroscopes and microsensors thanks to their high quality/reliability performances. To this end, this article is organized to examine the axial dynamic reaction of a rotating...
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Dynamic GNSS Mission Planning Using DTM for Precise Navigation of Autonomous Vehicles
PublicationNowadays, the most widely used method for estimating location of autonomous vehicles in real time is the use of Global Navigation Satellite Systems (GNSS). However, positioning in urban environments using GNSS is hampered by poor satellite geometry due to signal obstruction created by both man-made and natural features of the urban environment. The presence of obstacles is the reason for the decreased number of observed satellites...
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The influence of welding heat input on the quality and properties of high strength low-alloy dissimilar steel butt joints
PublicationThe paper presents the results of non-destructive and destructive tests of dissimilar highstrength low-alloy S460ML and S460N steel butt joints. These steels are characterized by similar mechanical properties, but their carbon equivalent CeIIW values are much different. The joints were made using different values of heat input for each welding bead. They were tested by non-destructive methods: visual, penetrant, radiographic and...
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Active Dynamic Infrared Thermal Imaging in Burn Depth Evaluation
PublicationThe aim of this study was to find the relationship between active dynamic thermography (ADT) with cold excitation and burn depth. This new modality of evaluation of burns seems to be an attractive proposal for quantitative classification, allowing proper choice of burn wound treatment: conservative or surgical, especially compared with static thermography. The work was an in vivo experiment on domestic pigs, and a small number...
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The Use of Unmanned Surface Vessels in Bathymetric Measurements of Waterbodies with Highly Dynamic Seafloor Relief
PublicationThe early 21st century is a time when unmanned surface vessels (USV) are used in various measurement applications. Modern autonomous and unmanned vessels are increasingly often used in bathymetric measurements whose aim is to measure the seafloor with the sufficient positioning accuracy. Therefore, the use of USVs in hydrography can be seen as the beginning of a new era in this regard. This paper presents bathymetric measurements...
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Path planning algorithm for ship collisions avoidance in environment with changing strategy of dynamic obstacles
PublicationIn this paper a path planning algorithm for the ship collision avoidance is presented. Tested algorithm is used to determine close to optimal ship paths taking into account changing strategy of dynamic obstacles. For this purpose a path planning problem is defined. A specific structure of the individual path and fitness function is presented. Principle of operation of evolutionary algorithm and based on it dedicated application...
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Parametric versus nonparametric modelling of dynamic susceptibility contrast enhanced MRI based data
PublicationDynamic tracking of a bolus of a paramagnetic agent (dynamic susceptibility contract - DSC) in MRI (magnetic resonance imaging) measurements is successfully used for assessment of the tissue perfusion and the other features and functions of the brain (i.e. cerebral blood flow - CBF, cerebral blood volume - CBV, mean transit time - MTT). The parametric and nonparametric approaches to the identification of MRI models are presented...
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Comparison of Properties of the Hybrid and Bilayer MWCNTs—Hydroxyapatite Coatings on Ti Alloy
PublicationCarbon nanotubes are proposed for reinforcement of the hydroxyapatite coatings to improve their adhesion, resistance to mechanical loads, biocompatibility, bioactivity, corrosion resistance, and antibacterial protection. So far, research has shown that all these properties are highly susceptible to the composition and microstructure of coatings. The present research is aimed at studies of multi-wall carbon nanotubes in three different...
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Mixed mechanical-metrological approach to quantify the fractographic damage in mechanical components subjected to cyclic loading
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Linear Time-Varying Dynamic-Algebraic Equations of Index One on Time Scales
PublicationIn this paper, we introduce a class of linear time-varying dynamic-algebraic equations (LTVDAE) of tractability index one on ar- bitrary time scales. We propose a procedure for the decoupling of the considered class LTVDAE. Explicit formulae are written down both for transfer operator and the obtained decoupled system. A projector ap- proach is used to prove the main statement of the paper and sufficient conditions of decoupling...
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Dynamic Headspace Sampling as an Initial Step for Sample Preparation in Chromatographic Analysis
PublicationThis work represents a brief summary of the use of dynamic headspace (DHS) as a technique for sample preparation in chromatographic analysis. Despite numerous developments in the area of analyte isolation and enrichment, DHS remains one of the fundamental methods used with GC. In our opinion, interest in this technique will not diminish significantly because it conforms to stipulations of green analytical chemistry. Moreover, DHS...
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The carbohydrate glycosylphosphatidylinositol anchor chain under mechanical stress
PublicationCarbohydrates have quite complicated micro heterogenic structure which may undergo different structural transitions. Due to their extreme flexibility it is very difficult to investigate such structural changes experimentally. In these studies we want to predict what structural and conformational changes are possible in the carbohydrate
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DYNAMIC ANALYSIS OF THE IMPACT OF VIBRATION ON HISTORICAL BUILDINGS - AN OWN PROJECT OF EXTERNAL STAIRCASE
PublicationThis article presents numerical simulations that concern modeling of interaction of the external staircase’s construction with the observation deck on historic water tower located at Gdansk University of Technology. The interaction occurring according to various methods of the staircase's construction support on the wall of the historic tower was compared. The external staircase that allows for entering onto the monument was subjected...
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Fading Characteristics for Dynamic Body-to-Body Channels in Indoor and Outdoor Environments
PublicationThis paper presents an analysis of the fading characteristics in dynamic body-to-body channels, based on measurements performed at 2.45 GHz in indoor and outdoor environments. The statistical analysis of the small- and large-scale fading shows that the Nakagami Distribution is the best model for the former and the Log-Normal one for the latter. An important influence of body shadowing...
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Dynamic analysis of temporary steel grandstand subjected to human-induced excitations due to jumping
PublicationSteel grandstands are structures that are frequently used during sport games and many other non-sporting events, such as festivals, music concerts, or even politicians rallies, with participation of a large number of attendees. Unfortunately, the presence of unexpected excessive dynamic loads due to unpredictable behaviour of spectators (e.g. synchronized harmonic jumping or swaying) may lead to...
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Application of Artificial Neural Networks to Predict Insulation Properties of Lightweight Concrete
PublicationPredicting the properties of concrete before its design and application process allows for refining and optimizing its composition. However, the properties of lightweight concrete are much harder to predict than those of normal weight concrete, especially if the forecast concerns the insulating properties of concrete with artificial lightweight aggregate (LWA). It is possible to use porous aggregates and precisely modify the composition...
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Identification of dynamic parameters in the context of diagnostics of steel tank with different level of liquid.
PublicationThe paper presents an experimental study to identify the dynamic parameters of a water-filled tank model. The experimental modal analysis approach involving the excitation at one point of the structure and acquisition of vibra tions at selected points distri buted over the tank surface allowed to determine the resonance frequencies, mode shapes and damping ratios. The main aim of the research was to examine the influence of...
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Modelling of Abdominal Wall Under Uncertainty of Material Properties
PublicationThe paper concerns abdominal wall modelling. The accurate prediction and simulation of abdominal wall mechanics are important in the context of optimization of ventral hernia repair. The shell Finite Element model is considered, as the one which can be used in patient-specific approach due to relatively easy geometry generation. However, there are uncertainties in this issue, e.g. related to mechanical properties since the properties...
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Development Of Dynamic Method For Evaluation Of Corrosion Rate On The Example Of Organic Corrosion İnhibitor
PublicationMeasurements of the corrosion rate belong to the most important aspects of materials science. In order to reduce material loss corrosion inhibitors are used. However selection of proper inhibitor should be based on evaluation of its mechanism and effective concentrations. Mechanism of inhibition usually has dynamic character so physicochemical parameters are changing in time. Most of actually used methods...
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Dynamic Charging of Electric Buses as a Way to Reduce Investment Risks of Urban Transport System Electrification
PublicationNight charging and fast charging are currently the two most common systems for charging electric buses. Despite the fact that numerous trial installations were started, neither of these two systems has obtained unqualified approval of the users. The alternative is to charge vehicles in motion - dynamic charging which combines the advantages of trolleybus transport and of electric buses. One of the advantages is the reduction of...
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Polygons vs. clumps of discs: A numerical study of the influence of grain shape on the mechanical behaviour of granular materials
PublicationWe performed a series of numerical vertical compression tests on assemblies 01 20 granular material using a Discrete Element code and studied the results with regard to the grain shape. The samples consist of 5000 grains made from either 3 overlapping discs (clumps - grains with concavities) or six-edged polygons (convex grains). These two grain type have similar external envelope, which is a fund ion of a geometrical parameter...
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Novel application of dynamic electrochemical impedance monitoring to a cataphoretic coating process
PublicationThe paper presents a novel method of on-line impedance monitoring of cataphoretic coating application process. Utilization of dynamic electrochemical impedance spectroscopy (DEIS) overcame the fundamental problem connected with non-stationarity of the aforementioned coating deposition process, which eliminates classical impedance spectroscopy technique from a real-time description of cataphoresis. The paper illustrates selected examples...
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ENERGY ANALYSIS OF PROPULSION SHAFT FATIGUE PROCESS IN ROTATING MECHANICAL SYSTEM PART I TESTING SIGNIFICANCE OF INFLUENCE OF SHAFT MATERIAL FATIGUE EXCITATION PARAMETERS
PublicationThe article discusses the problem of mathematical modelling of energy conversion processes in a rotating mechanical system for the purpose of identifying fatigue states of propulsion shafts in this system. A simplified physical model of the analysed system, constructed in an appropriate scale, has made the basis for the experimental research. The research programme took into consideration mechanical fatigue excitation of the model...
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DYNAMIC ANALYSIS OF HISTORIC RAILWAY BRIDGES IN POLAND IN THE CONTEXT OF ADJUSTING THEM TO PENDOLINO TRAINS
PublicationThe article presents the dynamic analysis of the historic railway bridge in Tczew as an example of the usefulness of such type of bridge for high-speed trains. The model of the bridge and the simulation of rolling stock passage was performed in SOFISTIK program. The scope of work includes experimental studies, the solution of the problem concerning the correct solution features dynamic model takes into account the dependencies...
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Analysis of a micro electro-mechanical platform for laparoscopic surgery
PublicationNiniejsza praca ma na celu określenie możliwości zastosowania odkształcalnych urządzeń o kinematyce równoległej w mikro robotycznych przegubach dla igło-laparoskopii. Operacje chirurgiczne przeprowadzane z użyciem narzędzi laparoskopowych o zmniejszonej średnicy nazywane są igłoskopią (z ang. needlescopy). Narzędzia te pozwalają na przeprowadzanie precyzyjnych operacji na stosunkowo niewielkim obszarze i z zaletami mało inwazyjnych...
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Stability evaluation of the marine propulsion unit mechanical system bymeans of vibrations measurements and their analysis.
PublicationIn paper selected issues concerning vibration diagnosis of the mechanical system within marine propulsion units have been given. The analysis of vibration parameters was carried out on the basis of experimental examinations of a real object in which an exceedance of the allowable vibration's level had been observed. In the beginning, the vibration apparatus being on laboratory equipment of the Department of Ship Power Plants of...
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Stability evaluation of the marine propulsion unit's mechanical system by means of vibration measurements and their analysis
PublicationIn this paper selected issues concerning vibration diagnosis of the mechanical system within marine propulsion units have been given. The analysis of vibration parameters was carried out on the basis of experimental examinations of a real object in which an exceedance of the allowable vibration's level had been observed. In the beginning, the vibration apparatus being on laboratory equipment of the Department of Ship Power Plants...
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Numerical analysis by FEM and analytical study of the dynamic thermal behavior of hollow bricks with different cavity concentration
PublicationThis paper presents the investigation results on the influence of the cavity concentration in hollow bricks on static and dynamic thermal parameters: a time lag, a decrement factor, an equivalent thermal diffusivity (ETD) and an equivalent thermal conductivity (ETC). The dynamic thermal behavior of hollow bricks is studied with an optimized cavity shape to reduce the intensity of radiation and convective heat exchange. The thermal...
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Numerical analysis by FEM and analytical study of the dynamic thermal behavior of hollow bricks with different cavity concentration
PublicationThis paper presents the investigation results on the influence of the cavity concentration in hollow bricks on static and dynamic thermal parameters: a time lag, a decrement factor, an equivalent thermal diffusivity (ETD) and an equivalent thermal conductivity (ETC). The dynamic thermal behavior of hollow bricks is studied with an optimized cavity shape to reduce the intensity of radiation and convective heat exchange. The thermal...
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Optimal Rotating Receiver Angles Estimation for Multicoil Dynamic Wireless Power Transfer
PublicationThis study proposed an approach to dynamic wireless charging that uses a rotating receiver coil. Our simulation study focused on the verification of a novel way of increasing the coupling coefficient and power transfer stability by following the flux of the transmitting coils. To obtain the highest possible coupling by means of the FEM analysis, we studied the optimization of the trajectory of the angular velocity of the rotating...