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Wyniki wyszukiwania dla: congestive heart failure
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HEART & LUNG
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HEART RHYTHM
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Heart and Metabolism
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Heart Views
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Partitioning total heart rate variability
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Nonlinear FEM 2D failure onset prediction of composite shells based on 6-parameter shell theory
PublikacjaWithin the framework of the nonlinear 6-parameter shell theory with the drilling rotation and asymmetric stress measures, the modifications of Tsai-Wu and Hashin laminate failure initiation criteria are proposed. These improvements enable to perform first ply failure estimations taking into account the non-symmetric stress measures. In order to check the validity of the proposed criteria, finite element analyses are performed with...
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Environmental failure of dental biomaterials
PublikacjaW pracy przedstawiono problematykę związaną z zagadnieniem trwałości biomateriałów stomatologicznych. Scharakteryzowano kryteria doboru materiałów i na przykładzie koron stomatologicznych pokazano wyniki oceny prawidłowości doboru w oparciu o metodę elementów skończonych. Przedstawiono wyniki weryfikacji doświadczalnej i wskazano na możliwości wykorzystania tej metody do konstruowania odpornych na zniszczenie koron metalowo-ceramicznych.
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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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Analysis of Failure Mechanism in Joints with Positive Eccentricity in CFS Truss
PublikacjaThe paper presents studies concerning the load-bearing capacity of truss joints with a positive eccentricity resulting from the arrangement of geometric members and the failure mechanisms observed in the joints. Based on the previously conducted experimental study, a numerical model of the tested fragment of the CFS truss with eccentricity in the joint was created and validated. All structural details of the tested truss and the...
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Post-failure fracture surface analysis of notched steel specimens after bending-torsion fatigue
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Relationship between heart rate variability, blood pressure and arterial wall properties during air and oxygen breathing in healthy subjects
PublikacjaPrevious studies reported that normobaric hyperoxia influences heart rate, arterial pressure, cardiac output and systemic vascular resistance, but the mechanisms underlying these changes are still not fully understood. Several factors are considered including degeneration of endothelium-derived nitric oxide by reactive oxygen species, the impact of oxygen-free radicals on tissues and alterations of autonomic nervous system function....
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Hyperventilation alters arterial baroreflex control of heart rate and muscle sympathetic nerve activity
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Tensile failure study of 3D printed PLA using DIC technique and FEM analysis
PublikacjaThe paper presents the experimental and numerical study of the failure behaviour of Fused Filament Fabricated (FFF) Polylactic Acid (PLA) samples subjected to tensile load. The examined samples are printed in flat orientation with 0◦, 45◦ and 90◦ raster angles. During the experiments the deformation of the specimens is continuously scanned with the 3D Aramis measuring system utilizing the digital imaging correlation technique,...
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Failure of austenitic stainless steel tubes during steam generator operation
PublikacjaThe article presents the failure process of austenitic stainless steels used in power devices, such as heat exchangers, steam generators, in terms of local corrosion: pitting, stress and intergranular corrosion, paying particular attention to welded joints area. The effect of steel chemical composition, microstructure, welding process and work environment was analyzed. The second part of the article presents the results of the...
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Impact of power electronic Var compensators installed in certain grid points on the voltage failure
PublikacjaThe article presents the test results of the various types of static compensators FACTS models in the power system. The basic case, which was analyzed, it was behavior of compensators which are installed in select points of the system during voltage failure. The article presents selected results of studies conducted as part of a work [2].
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Failure Monitoring and Condition Assessment of Steel-Concrete Adhesive Connection Using Ultrasonic Waves
PublikacjaAdhesive bonding is increasingly being incorporated into civil engineering applications. Recently, the use of structural adhesives in steel-concrete composite systems is of particular interest. The aim of the study is an experimental investigation of the damage assessment of the connection between steel and concrete during mechanical degradation. Nine specimens consisted of a concrete cube and two adhesively bonded steel plates...
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Failure of cylindrical steel silos composed of corrugated sheets and columns and repair methods using a sensitivity analysis
PublikacjaW artykule omówiono przypadek awarii metalowego silosu z blachy walcowej i pionowych słupów. Wykonano analizę wyboczeniową MES z uwzględnieniem imperfekcji geometrycznych. Omówiono metody naprawcze i ich optymalizację w oparciu o analizę wrażliwości.
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Wavelet Transform Analysis of Heart Rate to Assess Recovery Time for Long Distance Runners
PublikacjaThe diagnostics of the condition of athletes has become a field of special scientific interest and activity. The aim of this study was to verify the effect of a long (100 km) run on a group of runners, as well as to assess the recovery time that is required for them to return to the pre-run state. The heart rate (HR) data presented were collected the day before the extreme physical effort, on the same day as, but after, the physical...
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An approach for the response of buildings subjected to impact load after soft-story failure due to earthquake excitation
Publikacjahe soft-story failure is one of the most typical types of damage observed in buildings during earthquakes. The failure of an intermediate soft story of a structure results in large impact loading acting on the lower floors due to the fall of the upper stories. The aim of the present paper is to study the behavior of the structural members exposed to such extreme load conditions occurring under ground motion excitation. Special...
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Numerical Analysis of a Steel Frame Building with Soft-storey Failure under Ground Motion Excitation
PublikacjaThe aim of this paper is to show the results of a numerical analysis focused on the behaviour of multi-storey steel frame building that suffers from a soft-storey failure under ground motion excitation. A numerical model of the structure was created in FEM computer software and was exposed to an impact that would have been generated after a soft-storey failure due to falling of the upper floors. During the analysis, the whole structure...
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Statistical and fractal analysis of human heart dynamics.
PublikacjaPrzedstawiono sposób obliczania podstawowych i bardziej zaawansowanych (dyskrepancja) wielkości statystycznych do analizy dynamiki ludzkiego serca. Oprócz analizy statystycznej pokazano elementy analizy fraktalnej (wykresy Poincare). Przedstawiona analiza umożliwia wykrywanie patologicznych sytuacji i jest pomocna lekarzom w diagnostyce.
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Temporal Changes in Complexity of Cardiovascular Regulation during Head-Up Tilt Test by Entropic Measures of Fluctuations of Heart Period Intervals and Systolic Blood Pressure
PublikacjaTemporal changes in complexity of cardiovascular regulation during head-up tilt test by entropic measures of fluctuations of heart period intervals and systolic blood pressure
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Performance of isotropic constitutive laws in simulating failure mechanisms in scaled RC beams
PublikacjaResults of numerical calculations of reinforced concrete (RC) beams are presented. Based on experimental results on longitudinally reinforced specimens of different sizes and shapes are investigated. Four different continuum constitutive laws with isotropic softening are used: one defined within continuum damage mechanics, an elasto-plastic with the Rankine criterion in tension and the Drucker-Prager criterion in compression, a...
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Heart Rate Asymmetry, Its Compensation, and Heart Rate Variability in Healthy Adults during 48-h Holter ECG Recordings
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Estimation of Failure Initiation in Laminated Composites by means of Nonlinear Six-Field Shell Theory and FEM
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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An advanced tool integrating failure and sensitivity analysis into novel modeling of the stormwater flood volume
PublikacjaAn innovative tool for modeling the specific flood volume was presented that can be applied to assess the need for stormwater network modernization as well as for advanced flood risk assessment. Field measurements for a catchment area in Kielce, Poland, were used to apply the model and demonstrate its usefulness. This model extends the capability of recently developed statistical and machine learning hydrodynamic models developed...
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Study on deformed steel columns subjected to impact load due to soft-storey failure in buildings during earthquakes
PublikacjaThe so called soft-storey failure is one of the most typical types of damage induced in buildings as the result of earthquake excitation. It has been observed during ground motions that the failure of an upper soft storey of a structure results in large vertical impact load acting on the lower floors. If the resistance of the structural members of the lower storeys is not sufficient it may further lead to progressive collapse of...
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Assessment of Failure Occurrence Rate for Concrete Machine Foundations Used in Gas and Oil Industry by Machine Learning
PublikacjaConcrete machine foundations are structures that transfer loads from machines in operation to the ground. The design of such foundations requires a careful analysis of the static and dynamic effects caused by machine exploitation. There are also other substantial differences between ordinary concrete foundations and machine foundations, of which the main one is that machine foundations are separated from the building structure....
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Risk of power cables insulation failure due to the thermal effect of solar radiation
PublikacjaLow-voltage, as well as high-voltage power cable lines, are usually buried in the ground. The ampacity of the power cables in the ground mainly depends on the thermal resistivity of the soil, which may vary in a wide range. A common practice in power cable systems performance is to supply them from a pole of an overhead line. If so, a section of the line is located in free air and can be directly exposed to solar radiation. In...
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Laminated plates and shells - first ply failure analysis within 6-parameter shell theory
PublikacjaThis work describes Tsai-Wu and Hashin criteria modifications, dictated by nonlinear 6-parameter shell theory with asymmetric strain measures and drilling rotation. The material law is based on standard orthotropic elastic constants for a non-polar continuum, under plane state of stress. First ply failure loads of cylindrical panel subjected to pressure and flat compressed plate are estimated by means of Finite Element Analysis....
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Journal of Failure Analysis and Prevention
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Electronic Device Failure Analysis
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A framework to analyse the probability of accidental hull girder failure considering advanced corrosion degradation for risk-based ship design
PublikacjaShip’s hull girder failure could result from maritime accident that can cause human life loss, environmental disaster, and major economic impacts. In risk-based ship design paradigm, accounting for rare phenomena (e.g. ship-ship collision or grounding) is important to provide safe and durable structure. In-service corrosion-induced hull degradation should be considered at the design stage, as it can significantly affect structural...
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The non-invasive evaluation of heart function in patients with an acute myocardial infarction: The role of impedance cardiography
PublikacjaBackground: The purpose of this study was to analyze hemodynamic changes in patients treated with percutaneous coronary intervention (PCI) at an early stage of acute myocardial infarction (AMI) and at one-month follow-up. Methods: Patients with AMI (n = 27) who underwent PCI were analyzed using impedance cardiography (ICG). ICG data were collected continuously (beat by beat) during the whole PCI procedure and thereafter at every...
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Mariusz Kaczmarek dr hab. inż.
OsobyReceived M.Sc., Eng. in Electronics in 1995 from Gdansk University of Technology, Ph.D. in Medical Electronics in 2003 and habilitation in Biocybernetics and Biomedical Engineering in 2017. He was an investigator in about 13 projects receiving a number of awards, including four best papers, practical innovations (7 medals and awards) and also the Andronicos G. Kantsios Award and Siemens Award. Main research activities: the issues...
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Heart laceration during oesophagectomy for the treatment of oesophageal carcinoma
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Long-range dependencies in heart rate signals—revisited
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EDITORIALHypertension and cardiovascular disease: Is arterial stiffness the heart of the matter?
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Heart rate variability and functional outcome in ischemic stroke
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Heart rate asymmetry by Poincaré plots of RR intervals
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Analysis of correlation between heart rate and blood pressure
PublikacjaW artykule przedstawiono analizę korelacji pomiędzy częstością akcji serca (HR) i ciśnieniem krwi (BP). Wykorzystano rzeczywiste pomiary ciśnienia skurczowego i rozkurczowego krwi zmierzonego metodą inwazyjną w tętnicy promieniowej. Ze względu na możliwe zaszumienie sygnału przeanalizowano także dane po filtracji filttrem uśredniającycm oraz wykonano analizę trendów sygnałów. Wyniki analizy zarówno danych pomiarowych jak i filtrowanych...
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HEART
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Pertussis: History of the Disease and Current Prevention Failure
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Creep failure prediction of pipelines in elevated temperature
PublikacjaW pracy omówiono zastoswanie modelu konstytutytwnego pełzania pozwalającego na analizę trwałości metalowych ruruciągów pracujących w wysokich temperaturach. Zaprezentowano wyniki obliczeń opartych na metodzie elementów skończonych (MES) wykonanych z wykorzystaniem procedur użytkownika w komercyjnym programie MES. Porównano wyniki dla dwóch typów 4-węzłowych elementów powłokowych.
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Increasing rail life by forecasting fatigue failure.
PublikacjaReferat poświęcony jest przedłużaniu żywotności szyn i obejmuje zagadnienia prognozowania liczby pęknięć a także planowania szlifowań szyn. Dane pomiarowe pochodzą z wieloletnich badań przeprowadzonych w Katedrze Inżynierii Kolejowej Politechniki Gdańskiej na liniach magistralnych PKP.
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The influence of selected strain-based failure criteria on ship structure damage resulting from a collision with an offshore wind turbine monopile
PublikacjaOffshore wind farms are developing well all over the world, providing green energy from renewable sources. The evaluation of possible consequences of a collision involves Finite Element computer simulations. The goal of this paper was to analyse the influence of selected strain-based failure criteria on ship damage resulting from a collision with an offshore wind turbine monopile. The case of a collision between an offshore supply...
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Egyptian Heart Journal
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IJC Heart & Vasculature
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Heart Lung and Vessels
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Congenital Heart Disease
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