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Search results for: HEART VALVES
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Numerical model for thin liquid film with evaporation and condensation on solid surfaces in systems with conjugated heat transfer
PublicationCondensation and evaporation processes from wetted surfaces are of utmost importance in many technological or industrial applications. In many devices such as home-appliances and air conditioning systems just to name a few, condensation and evaporation processes greatly impact their performance and energy efficiency; The physics of these processes is quite complex, involving conjugate heat transfer among solid–liquid film-gaseous...
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Preliminary results from HEDGEHOG REXUS Project - sounding rocket experiment on accelerations, vibrations and heat flow
PublicationAs access to space conditions becomes more available, both technically and economically, scientists' interest in launching finer and more sophisticated experiments grows. This applies now more than ever to fragile by nature biological and chemical experiments. To be qualified for launch, such experiments need to be carefully tested prior to the event. The tests should represent actual launch conditions as closely and in as detailed...
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Preliminary results from HEDGEHOG REXUS project – A sounding rocket experiment on accelerations, vibrations and heat flow
PublicationDuring flight, a sounding rocket is subject to a unique environment - severe vibrations and substantial heat flux. In order to design payloads, precise measurement of these conditions is required. This paper presents preliminary results from HEDGEHOG REXUS Project, whose scientific goal was to characterise the thermal and dynamic environment of REXUS sounding rockets. For this purpose, two new sensors have been designed - mechanical...
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Thermal and economic investigation of straight and U-bend double tube heat exchanger with coiled wire turbulator
PublicationExperimental research has been carried out for four individual heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain U-bend and U-bend with turbulator. Tests were made for the water-water system. The study covered a wide measuring range, i.e., Re = 800–9000 – on the shell side, for a constant cold water temperature of 9 ◦C and hot water of 50 ◦C. The heat exchangers were made from copper tubes with...
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Computational fluid dynamics simulation of heat transfer from densely packed gold nanoparticles to isotropic media
PublicationThis work aims to determine and compare heat generation and propagation of densely packed gold nanoparticles (Au NPs) induced by a resonant laser beam (532 nm) according to the Mie theory. The heat flux propagation is transferred into the materials, which here are: silica glass; soda-lime-silica glass; borosilicate glass; polymethyl methacrylate (PMMA); polycarbonate (PC); and polydimetylosiloxane (PDMS). This analysis aims to...
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Improved finite element method for flow, heat and solute transport of Prandtl liquid via heated plate
PublicationIn the current study, a vertical, 3D-heated plate is used to replicate the generation of heat energy and concentration into Prandtl liquid. We discuss how Dufour and Soret theories relate to the equations for concentration and energy. In order to see how efectively particles, interact with heat and a solvent, hybrid nanoparticles are used. It does away with the phenomena of viscous dissipation and changing magnetic felds. The motivation...
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Promising Nanoparticle-Based Heat Transfer Fluids—Environmental and Techno-Economic Analysis Compared to Conventional Fluids
PublicationProviding optimal operating conditions is one of the major challenges for effective heating or cooling systems. Moreover, proper adjustment of the heat transfer fluid is also important from the viewpoint of the correct operation, maintenance, and cost efficiency of these systems. Therefore, in this paper, a detailed review of recent work on the subject of conventional and novel heat transfer fluid applications is presented. Particular...
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Analysis of Organic Rankine Cycle efficiency and vapor generator heat transfer surface in function of the reduced pressure
PublicationIn the paper presented is analysis of the influence of reduced pressure on efficiency and heat transfer area of vapor generator of Organic Rankine Cycle (ORC) in case of subcritical and supercritical parameters of operation. Compared are two cases of subcritical and supercritical ORC featuring a similar arrangement of heat source supply and heat removal, that is featuring the same temperatures of working fluid before the turbine,...
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Long-term mortality after transcatheter aortic valve implantation for aortic stenosis in immunosuppression-treated patients: a propensity-matched multicentre retrospective registry-based analysis
PublicationIntroduction Data regarding patients with a previous medical record of immunosuppression treatment who have undergone transcatheter aortic valve implantation (TAVI) are limited and extremely inconclusive. Available studies are mostly short term observations; thus there is a lack of evidence on efficacy and safety of TAVI in this specific group of patients. Aim To compare the in-hospital and long-term outcomes between patients...
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Determination of time delay between ventricles contraction using impedance measurements
PublicationThe paper presents a novel approach to assessment of ventricular dyssynchrony basing on multichannel electrical impedance measurements. Using a proper placement of electrodes, the sensitivity approach allows estimating time difference between chambers contraction from over determined nonlinear system of equations. The theoretical considerations which include Finite Element Method simulations were verified using measurements on...
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China’s international trade and global value chains under One-Belt One-Road initiative
PublicationResearch background: After China acceded to the WTO in 2001, its foreign trade has expanded rapidly to be the largest share in the world. However, China's economic development changing from high-speed growth to medium high-speed growth in recent years. At the same time, the increase in labour cost and overcapacity also hinder China’s international trade. In order to solve these challenges and strengthening ties...
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Effect of Drip Fertigation with Nitrogen on Yield and Nutritive Value of Melon Cultivated on a Very Light Soil
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Value of Personalized Dementia-Specific Quality of Life Scales: An Explorative Study in 3 European Countries
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Ammonium Enhances Food Waste Fermentation to High-Value Optically Active l-Lactic acid
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Positive solutions to second order four-point boundary value problems for impulsive differential equations
PublicationPraca dotyczy problemów brzegowych dla równań różniczkowych drugiego rzędu z impulsami. Podane zostały warunki dostateczne na istnienie trzech dodatnich rozwiązań takich problemów z czteropunktowymi warunkami brzegowymi. W badaniach korzystano z twierdzenia Leggetta-Williamsa.
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Volunteerism in the last year as a moderator between empathy and altruistic social value orientation: An exploratory study
PublicationVolunteerism is a sustained prosocial activity, and young adults are one of the most important targets for organizations recruiting volunteers. Empathy and altruistic social value orientation measured by a decomposed game are dispositional traits that might foster engagement in volunteerism. Using a self-report online-based questionnaire study on two groups of young adults (aged 18-35, N = 224 non-volunteers and N = 178 volunteers...
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Conversion of Geraniol into Useful Value-Added Products in the Presence of Catalysts of Natural Origin: Diatomite and Alum
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Solvability of three point boundary value problems for second order differential equations with deviating arguments
PublicationBadano problem istnienia rozwiązań dla równań różniczkowych rzędu drugiego z trzypunktowymi warunkami brzegowymi. Podano warunki dostateczne dla istnienia ekstremalnych lub kwazi-ekstremalnych rozwiązań powyższych problemów. Przedmiotem badań były również nierówności różniczkowe z odchylonymi argumentami.
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A new modelling arrangement for testing of Catenary Anchoring Leg Mooring (CALM) system behaviour in waves
PublicationW artykule przedstawiono układ modelowy pławy cumowniczo-przeładunkoweji łańcuchów kotwicznych możliwy do realizacji w wydłużonych basenach falowych służących na co dzień do badania właściwości morskich statków. System łańcuchów kotwicznych sprowadzono do płaszczyzn równoległych do osi basenu i połączono z pławą cienkimi linkami stalowymi przechodzącymi przez bloczki kierunkujące. Opisywany układ pozwolił na przeprowadzenie badań...
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Count Data Modeling About Relationship Between Dubai Housing Sales Transactions and Financial Indicators
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The Prognostic Value of PI-RADS Score in CyberKnife Ultra-Hypofractionated Radiotherapy for Localized Prostate Cancer
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Studying the Influence of the Impact Gap Value on the Average Translational Speed of the Wheeled Vibration-Driven Robot
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Damage detection strategies for aircraft shell-like structures based on propagation guided elastic waves
PublicationW pracy przedstawiono mozliwości detekcji uszkodzeń w lotniczych konstrukcjach powłokowych z wykorzystaniem fal sprężystych. Omówiono kilka strategii detekcji uszkodzeń. Przedstawiono wyniki symulacji numerycznych z wykorzystaniem metody spektralnych elementów skończonych, jak również wynik badań eksperymentalnych z zastosowaniem wibrometrii laserowej.
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REVERSE MODELLING OF MICROSEISMIC WAVES PROPAGATION FOR THE INTERPRETATION OF THE DATA FROM HYDRAULIC FRACTURING MONITORING IN POLAND
PublicationA hydraulic fracturing job was performed to stimulate gas flow from a horizontal wellbore located in Poland. The whole operation was overseen by means of microseismic monitoring. For this purpose, an array of 12000 geophones was deployed on ground in form of patches distributed unevenly in a region of 4km from the wellbore. The array was constantly recording seismic signals during whole fracturing processed. Such recorded signals...
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Elastic waves in the railroad track substructures and its surroundings analyzed with non-classical operational methods
PublicationWe analyze the propagation of the waves generated by the rolling stock and the interaction of those waves on the medium and its surroundings. We use non-classical operational methods for monitoring construction of the railway infrastructure and for noise damping.
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Global Value Chains and Wages: Multi-Country Evidence from Linked Worker-Industry Data
PublicationThis paper uses a multi-country microeconomic setting to contribute to the literature on the nexus between production fragmentation and wages. Exploiting a rich dataset on over 110,000 workers from nine Eastern and Western European countries and the United States, we study the relationship between individual workers’ wages and industry ties into global value chains (GVCs). We find an inverse (but weak) relationship between the...
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Modelling of residential sales price with kriging using different distance metrics in different correlation functions
PublicationThe modelling and estimation of sales prices based on economical conditions are important for housing sector especially in developing countries. Analysts are focused on the subject to analyze price movements and estimate the future trend of the sales prices for housing sector. In this study, we tried to generate a robust and efficient model related to the subject. Firstly, we investigated economic variables affecting housing sales...
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Count Data Modeling About Relationship Between Dubai Housing Sales Transactions and Financial Indicators
PublicationIn this study, illustrating and comparing the performances of count data models such as Poisson, negative binomial (NB), Hurdle and zero-inflated models for the determination of factors affected housing sales in Dubai. Model comparisons are made via Akaike’s information criterion (AIC), the Vuong test and examining the residuals. Main purpose of this study is building reliable statistical model for relationship between Dubai housing...
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On the well posedness of static boundary value problem within the linear dilatational strain gradient elasticity
PublicationIn this paper, it is proven an existence and uniqueness theorem for weak solutions of the equilibrium problem for linear isotropic dilatational strain gradient elasticity. Considered elastic bodies have as deformation energy the classical one due to Lamé but augmented with an additive term that depends on the norm of the gradient of dilatation: only one extra second gradient elastic coefficient is introduced. The studied class...
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Analysis of the influence of external conditions on temperature readings in thermograms and adaptive adjustment of the measured temperature value
PublicationMeasuring human temperature is a crucial step in preventing the spread of diseases such as COVID-19. For the proper operation of an automatic body temperature measurement system throughout the year, it is necessary to consider outdoor conditions. In this paper, the effect of atmospheric factors on facial temperature readings using infrared thermography is investigated. A thorough analysis of the variation of facial temperature...
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Impact of Propeller Emergence on Hull, Propeller, Engine, and Fuel Consumption Performance in Regular Head Waves
PublicationIn this study, the impact of propeller emergence on the performance of a ship (speed), propeller (thrust, torque, and RPM), a diesel engine (torque and RPM) and fuel consumption are analysed under severe sea conditions. The goal is to describe the variation in the system variables and fuel consumption rather than analysing the motion of the ship or the phenomenon of propeller ventilation in itself. A mathematical model of the...
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Wage determination, Global Value Chains and role played by wage bargaining schemes: The case of Poland
PublicationThis study examines the linkages between GVC involvement and wages in Poland given different wage bargaining schemes. The analysis is based on microdata from the European Structure of Earnings Survey for Poland combined with sectoral data from the World Input-Output Database. In particular, two measures of GVC involvement were used: the share of foreign value added (FVA) to export and the measure of traditional offshoring. The...
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The role of additives in improving the flammability and calorific value of leather shavings and the binding of chromium compounds in ash
PublicationLeather processing companies are struggling with the problem of increasing costs of post-production waste disposal. Therefore, the issue of thermal waste disposal at the plant and the use of generated heat in the production process is becoming more and more popular. Leather waste on its own does not allow for autothermal combustion despite the sufficient higher heating value (HHV). Therefore the Authors proposed to improve the...
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Evaluation of Response Amplitude Operator of Ship Roll Motions Based on the Experiments in White Noise Waves
PublicationEvaluation of the response amplitude operator (RAO) function for ship wave frequency motions by means of scale model tests in regular waves is a standard procedure conducted by hydrodynamic model testing institutions. The resulting RAO function allows for evaluating sufficiently reliable seakeeping predictions for low to moderate sea states. However, for standard hull forms, correct prediction of roll motion in irregular wave (and...
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The added value of using the HEPA PAT for physical activity policy monitoring: a four-country comparison
PublicationBackground Public policy is increasingly recognized as an important component of physical activity promotion. This paper reports on the current status of physical activity policy development and implementation in four European countries based on the Health-Enhancing Physical Activity Policy Audit Tool (HEPA PAT) developed by WHO. It compares the findings to previous studies and discusses the general utility of this tool and its...
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Room temperature depinning of the charge-density waves in quasi-two-dimensional 1T-TaS2 devices
PublicationWe report on the depinning of nearly commensurate charge-density waves in 1T-TaS2 thin films at room temperature. A combination of the differential current–voltage measurements with the low-frequency noise spectroscopy provides unambiguous means for detecting the depinning threshold field in quasi-2D materials. The depinning process in 1T-TaS2 is not accompanied by an observable abrupt increase in electric current—in striking contrast...
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Impact of polder flood plain of the Cisowska Struga on the transformation of flood waves between Gdynia and Rumia
PublicationThe paper presents the results of hydraulic calculations (numerical simulations), which were made to investigate the role of floodplain (polder) adjacent to the left bank of Cisowska Struga in Gdynia downstream Hutnicza St. in the process of retention and transformation of flood waves occurring in this river due to torrential rainfall. The paper also addressed the issue of the impact of potential changes in the development of the...
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Commitment Ladder in the Relationship between Service Providers and Customers as Added Value in Sustainable Services Development
PublicationThe socioeconomic sphere and the relationships in which commitment occurs are important elements in the development of sustainable services. The study reported in this article identifies the elements that influence the development of the relationship between service providers and their customers and proposes a model that describes the state of the relationship between service providers and customers in terms of symmetrical commitment...
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EXPERIMENTAL AND NUMERICAL INVESTIGATION ON SPECIMEN GEOMETRY EFFECT ON THE CTOD VALUE FOR VL-E36 SHIPBUILDING STEEL
PublicationThere are special cases in the marine industry, where additional material tests, such as the fracture toughness test, must be performed. Additional fracture toughness tests, such as CTOD (Crack Tip Opening Displacement), are typically performed on three-point bend specimens. The dimension that defines all the specimen dimensions is the thickness of the material to be tested. It is recommended by classification societies (e.g. DNVGL)...
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Modeling process of planning finished product sales volumes at industrial enterprises in modern economic conditions
PublicationThis article presents improving the existing system of planning finished products sales volumes. The influencing factors of the sales volumes in modern economic conditions have been determined: falling world oil prices, the reduction of pipe consumption in the domestic market, the global pandemic. The algorithm of planning finished products sales volumes has been constructed. Calculations based on the Holt forecasting method has...
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The impact of China’s One-Belt One-Road initiative on international trade and global value chains
PublicationThis study examines the potential effects of China’s ‘One-Belt One-Road’initiative (OBOR) on trade flows and global value chain (GVC) connections.The empirical analysis is based on the augmented trade gravity model, which comprises 186 economies and 199 of their partners from 2000 to 2018. We also estimate the gravity model for involvement in GVC (domestic value added in intermediate exports, foreign value added in exports, and...
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Application of the Bodner-Partom constitutive equations for modelling of the technical fabric Valmex used for the hanging roof of the Forest Opera in Sopot
PublicationThe study of an inelastic properties of the technical fabric Valmex used for 20 years as the roof structure of the Forest Opera in Sopot (Poland) is presented. The uniaxial tensile laboratory tests with constant strain rate have been conducted and analysed. Parameters of the Bodner-Partom constitutive model have been identified and verified by numerical simulations. Two approaches of the parameters identification have been proposed:...
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A GPU Solver for Sparse Generalized Eigenvalue Problems with Symmetric Complex-Valued Matrices Obtained Using Higher-Order FEM
PublicationThe paper discusses a fast implementation of the stabilized locally optimal block preconditioned conjugate gradient (sLOBPCG) method, using a hierarchical multilevel preconditioner to solve nonHermitian sparse generalized eigenvalue problems with large symmetric complex-valued matrices obtained using the higher-order finite-element method (FEM), applied to the analysis of a microwave resonator. The resonant frequencies of the low-order...
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Entropic Measures of Complexity of Short-Term Dynamics of Nocturnal Heartbeats in an Aging Population
PublicationTwo entropy-based approaches are investigated to study patterns describing differences in time intervals between consecutive heartbeats. The first method explores matrices arising from networks of transitions constructed following events represented by a time series. The second method considers distributions of ordinal patterns of length three, whereby patterns with repeated values are counted as different patterns. Both methods provide...
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Comparison the heat load as the results of tests on human subject in a hot environment with the results obtained from numerical simulation
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Mycobacterium tuberculosis Complex and Mycobacterial Heat Shock Proteins in Lymph Node Tissue from Patients with Pulmonary Sarcoidosis
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Modeling of heat and fluid flow in granular layers using high-order compact schemes and volume penalization method
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Theoretical analysis of heat transfer between a liquid layer formed by an impinginf gas liquid jet AND a solid surface
PublicationHeat transfer phenomenon between a horizontal solid surface and a liquid layer created on a surface by an axisymmetrical liquid gas impinging jet has been analysed. The analytical treatment of the phenomenon is devoted to the area whose diameter is lower than the diameter of the hydraulic jump. W pracy przedstawiono teoretyczną analizę wymiany ciepła pomiędzy warstwą cieczy a stałą powierzchnią po której przepływa.
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Improved semi-empirical method for determination of heat transfer coefficient in flow boiling in conventional and small diameter tubes
PublicationPraca dotyczy przedstawienia poprawionego modelu umożliwiającego wyznaczanie współczynnika przejmowania ciepła w kanałach o małych średnicach jaj i tych tradycyjnych. Model zweryfikowano na 6 czynnikach chłodnuiczych uzyskując bardzo zadowalającą zgodność.
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A semi-empirical method for calculation of flow boiling heat transfer coefficients for conventional channels and small diameter tubes
PublicationW pracy przedstawiono rozważania na temat modelowania dwufazowego przepływu wrzącego w kanałach konwencjonalnych i w kanałach o małej średnicy. Przedstawiono modyfikację korelacji zaproponowanej wcześniej przez J. Mikielewicza na podstawie nowych danych eksperymentalnych, uzyskanych dla kanałów o małej średnicy. Bank danych obejmował ponad 460 punktów pomiarowych dla czynników R141b, R134a, R113, R123, R12, R11 i wody. Uzyskano...