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Activated Tungsten Inert Gas Weld Characteristics of P91 Joint for Advanced Ultra Supercritical Power Plant Applications
PublikacjaActivated Tungsten Inert Gas (A-TIG) welding, a variant of tungsten inert gas (TIG) welding, was used for welding P91. In Generation IV power plants, P91 welds are prone to premature failure due to the presence and formation of brittle phases and creep at high temperatures. When performing A-TIG welding, the flux composition plays a role in the reversal of the Marangoni flow in the weld pool, which ultimately determines the level...
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Non-destructive inspection of ground anchors using guided wave propagation
PublikacjaThis paper deals with numerical and experimental investigations of specific problems of guided wave propagation in ground anchors. The research focuses on recognizing the phenomenon of the energy transfer between anchor components. Particular attention is paid to characteristic features of guided waves propagating in free and embedded parts of the tendon, at the interface between the tendon and the surrounding anchor body as well...
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CHARACTERIZATION STUDY ON MECHANICAL PROPERTIES OF POLYESTER COATED FABRIC
PublikacjaThe scope of the paper is to determine the mechanical properties of the Precontraint 1302 polyester coated fabric under uniaxial and biaxial tensile tests. The results are compared for Precontraint 1302 fabric and other types of coated fabrics. The author applied an orthotropic model and a dense net model to reflect the polyester coated fabric performance under uniaxial and biaxial tensile tests. Material parameters are specified...
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Structural Assessment of Reinforced Concrete Beams Incorporating Waste Plastic Straws
PublikacjaThe behavior of reinforced concrete beams containing fibers made of waste plastic straws (WPSs) under the three point bending test is examined. The effect of WPS fiber addition on the compressive and split tensile strength is reported. Four concrete mixes were prepared. The control mix PS-0 had a proportion of 1 cement: 1 sand: 2 coarse aggregate and a water cement ratio of 0.4. In the other three mixes PS-0.5, PS-1.5 and PS-3,...
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Navigating the complexities of altruistic helping in Nonprofit Organizations: An analysis of Benefits, Burdens and managerial challenges
PublikacjaWe investigate how individuals cope with side effects of altruistic behaviour at work, i.e. genuine helping behaviour which is not part of any job description, and what role the organizational context plays in these dynamics. Employing simultaneous dyadic interviews, we show how employees of non-profit organizations cope with undesired effects of altruistic help. Our data provides evidence of unintended outcomes for the individual...
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Application of surface active amino acid ionic liquids as phase-transfer catalyst
PublikacjaFive structurally related morpholinium derived ionic liquids containing N-acetyl-glycinate anion were synthesized and their thermal stability, surface properties and activity as phase transfer catalysts investigated. The thermal properties were studied by differential scanning calorimetry, while the adsorption at the air/water interface and micellization behavior was analyzed by surface tension measurements, conductometry and isothermal...
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EXPERIMENTAL VERIFICATION OF THE METHOD OF FLOW BOILING AND FLOW CONDENSATION HEAT TRANSFER PREDICTION FOR SELECTED FLUIDS
PublikacjaIn the paper presented are the results of calculations using authors own model to predict heat transfer coefficient during flow boiling of different refrigerants. The experimental data from various research studies from literature were collected. Calculations were conducted for a full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in- house developed model....
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Calculation method for flow boiling and flow condensation of R134a and R1234yf in conventional and small diameter channels
PublikacjaThe paper presents the results of calculations performed using the authors’ model to predict the heat transfer coefficient during flow boiling for two refrigerants R134a and R1234yf. The experimental data from various past studies have been collected and the calculations have been conducted for the full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house...
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Exploring contexts of use of cultural objects in virtual museums
PublikacjaThis paper presents a system which facilitates discovering knowledge about cultural objects. The system is based on semantic modeling of a virtual museum which consists of cultural objects placed in a virtual 3D space. The article describes an extension to the concept of cultural objects which includes information on the use of these objects. This extension enables to place objects in an appropriate context in a virtual museum....
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Determination of Mechanical Properties of P91 Steel by Means of Magnetic Barkhausen Emission
PublikacjaIn this work, an attempt at determination of mechanical properties by means of a method based on magnetic Barkhausen emission measurements was proposed. The specimens made of P91 steel were subjected to creep or plastic flow which were interrupted after a range of selected time periods in order to achieve specimens with an increasing level of strain. Subsequently, measurements of magnetic Barkhausen emission were carried out, and...
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FEX a Fingers Extending eXoskeleton for Rehabilitation and Regaining Mobility
PublikacjaThis paper presents the design process of an exoskeleton for executing human fingers’ extension movement for the rehabilitation procedures and as an active orthosis purposes. The Fingers Extending eXoskeleton (FEX) is a serial, under-actuated mechanism capable of executing fingers’ extension. The proposed solution is easily adaptable to any finger length or position of the joints. FEX is based on the state-of-art FingerSpine serial...
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Correction to: Azo group(s) in selected macrocyclic compounds
PublikacjaIn the original publication of the article, a part of Scheme 12 was missed. The correct version of Scheme 12 was provided in this correction article. The original article has also been corrected.
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Styrene-Butadiene Rubber/Modified Ground Tire Rubber Blends Co-Vulcanization: Effect of Accelerator Type
PublikacjaGround tire rubber was thermo-mechanically modified with using a co-rotating twin screw extruder. Modification of GTR was conducted in autothermal conditions. Styrene-butadiene rubber and modified ground tire rubber blends were prepared via two-roll milling. Obtained compounds were cured with conventional system (sulfur/vulcanization accelerator ratio was 2:1). During this research three commonly vulcanization accelerators (MBT,...
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A new index for statistical analyses and prediction of travelling ionospheric disturbances
PublikacjaTravelling Ionospheric Disturbances (TIDs) are signatures of atmospheric gravity waves (AGWs) observed in changes in the electron density. The analysis of TIDs is relevant for studying coupling processes in the thermosphere–ionosphere system. A new TID index is introduced, which is based on an easy extension of the commonly used approach for TID detection. This TID activity index, which can be applied for individual Global Navigation...
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Prediction of flow boiling heat transfer data for R134a, R600a and R290 in minichannels
PublikacjaIn the paper presented is the analysis of the results of calculations using a model to predict flow boiling of refrigerants such as R134a, R600a and R290. The latter two fluids were not used in development of model semiempirical correction. For that reason the model was verified with present experimental data. The experimental research was conducted for a full range of quality variation and a relatively wide range of mass velocity....
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Orientation effects on the fracture behaviour of additively manufactured stainless steel 316L subjected to high cyclic fatigue
PublikacjaIn this paper, stainless steel 316L (SS316L) bars were additively manufactured (AM) in three orientations (Z – vertical, XY – horizontal, ZX45 – midway between vertical and horizontal) by using the Laser Powder Bed Fusion Melting (LPBF-M) method. The AM specimens were subjected to load control fatigue testing under full tension and compression (R = -1) at stress amplitudes ±350, ±400 and ±450 MPa. The XY and ZX45 printing orientations...
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Dynamic polarizability of the relativistic hydrogenlike atom: Application of the Sturmian expansion of the Dirac-Coulomb Green function
PublikacjaWe utilize the Sturmian expansion of the Dirac-Coulomb Green function [R. Szmytkowski, J. Phys. B 30, 825 (1997)] to obtain components of the dynamic dipole polarizability tensor of the relativistic hydrogenlike atom in the ground state. It is found that the tensor may be expressed in terms of two independent quantities: a scalar polarizability and a vector polarizability, the latter being of the relativistic origin. In the static...
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Facing the brainstorming theory. A case of requirements elicitation
PublikacjaKnowledge is still considered to be power and its externalization makes it possible for others to use that power. In this paper, we examine the theory of brainstorming, and the claim by father Alex Osborn that in a group session an individual can think of twice as many ideas than working alone. In the context of requirements elicitation, we performed an experiment on a “nominal” and a “real” group of participants, following a procedure...
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Modyfikacja kompozytów elastomerowych NR za pomocą ligniny i glicerolizatu
PublikacjaPrzedmiotem opisanych w niniejszym artykule badań są wulkanizaty kauczuku naturalnego. Celem pracy było zbadanie wpływu ligniny oraz glicerolizatu na wybrane właściwości kompozytów zawierających kauczuk naturalny. Strukturę chemiczną przygotowanych materiałów potwierdzono, wykorzystując analizę spektroskopową w podczerwieni (FTIR). Zbadano również właściwości mechaniczne przy statycznym rozciąganiu, twardość, ścieralność oraz odbojność...
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Assessment of FSW Welds Made of Aluminum Alloy AW7075-T651.
PublikacjaThis paper summarizes the results of experimental studies in which the aluminum alloy AW7075-T651 was friction stir welded (FSW) using various combinations of process parameters (rotational - R and travel speed - T). Mechanical properties of the test welds were assessed by using static tensile test and Vickers hardness measurement. The temperature of the welded plates was monitored during welding by means of thermocouples placed...
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Microstructure and Mechanical Properties of Carboxylated Nitrile Butadiene Rubber/Epoxy/XNBR-grafted Halloysite Nanotubes Nanocomposites
PublikacjaThe effect of various amounts of carboxylated nitrile butadiene rubber (XNBR) functionalized halloysite nanotubes (XHNTs) on the cure characteristics, mechanical and swelling behavior of XNBR/epoxy compounds was experimentally and theoretically investigated. The morphology of the prepared XNBR/epoxy/XHNTs nanocomposites was imaged using scanning electron microscopy (SEM). The effects of various XNBR-grafted nanotubes on the damping...
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The effect of macro polymer fibres length and content on the fibre reinforced concrete
PublikacjaThe paper presents studies of a ready-mix concrete containing polymer fibres of three different lengths: 24, 38 and 54 mm. The performed tests allowed to determine the effect of fibre volume fraction and length on the concrete strength. The basic parameters of concrete mixture (consistency, air content and bulk density) were identified. Fibre reinforced concrete belongs to a group of composite materials. The polymer fibres are...
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A Parallel MPI I/O Solution Supported by Byte-addressable Non-volatile RAM Distributed Cache
PublikacjaWhile many scientific, large-scale applications are data-intensive, fast and efficient I/O operations have become of key importance for HPC environments. We propose an MPI I/O extension based on in-system distributed cache with data located in Non-volatile Random Access Memory (NVRAM) available in each cluster node. The presented architecture makes effective use of NVRAM properties such as persistence and byte-level access behind...
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FE analysis of a coupled energetic-statistical size effect in plain concrete beams with varying material properties.
PublikacjaThe numerical FE investigations of a coupled energetic-statistical size effect in unnotched concrete beams of similar geometry under quasi-static three point bending were performed within elasto-plasticity with non-local softening. The stochastic FE analyses were carried out with three different beam sizes. Deterministic calculations were performed with the uniform distribution of a uniaxial tensile strength. In statistical calculations...
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Diagnostyka ultradźwiękowa mostowej belki prefabrykowanej typu T metodą młoteczkową
PublikacjaZastosowanie prefabrykacji w budowie obiektów mostowych pozwala optymalizować zużycie energii i materiałów i tym samym redukować koszty budowanego obiektu. Prefabrykowane belki sprężone mogą występować jako elementy kablobetonowe wykonywane bezpośrednio na placu budowy lub powstawać w zakładzie prefabrykacji jako elementy strunobetonowe. Elementy prefabrykowane wytwarzane w warunkach przemysłowych muszą spełniać wymagania wysokiej trwałości,...
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Topological degree for equivariant gradient perturbations of an unbounded self-adjoint operator in Hilbert space
PublikacjaWe present a version of the equivariant gradient degree defined for equivariant gradient perturbations of an equivariant unbounded self-adjoint operator with purely discrete spectrum in Hilbert space. Two possible applications are discussed.
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Lasing modes of infinite periodic chain of quantum wires
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Effective mode volume of a natural mode of an open dielectric resonator with an active region
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Plasmon and structure resonances in the scattering of light by a periodic chain of silver nanocylinders
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Periodicity-induced effects in the scattering and absorption of light by infinite and finite gratings of circular silver nanowires
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On tracking properties of real-valued generalized adaptive notch filters
PublikacjaGeneralized adaptive notch filters (GANFs) are used for identification/tracking of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. The paper presents results of local performance analysis of a real-valued GANF algorithm, i.e., algorithm designed to track parameters of a real-valued system. This is an extension of the previous work which focused...
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Acceleration waves in the nonlinear micromorphic continuum
PublikacjaWithin the framework of the nonlinear elastic theory of micromorphic continua we derive the conditions for propagation of acceleration waves. An acceleration wave, also called a wave of weak discontinuity of order two, can be treated as a propagating nonmaterial surface across which the second derivatives of the placement vector and micro-distortion tensor may undergo jump discontinuities. Here we obtain the acoustic tensor for...
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Linear viscoelastic transversely isotropic model based on the spectral decomposition of elasticity tensors
PublikacjaThe linear viscoelasticity is still a useful model in the engineering for studying the behavior of materials loaded with different loading rates (frequencies). Certain types of materials reveal also an anisotropic behavior: fiber reinforced composites, asphalt concrete mixtures, or wood, to name a few. In general, researchers try to identify experimentally the dependence of engineering constants like: directional Young’s moduli...
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Parameters’ Identification of Perzyna and Chaboche Viscoplastic Models for Aluminum Alloy at Temperature of 120◦C
PublikacjaThe main purpose of this paper is the parameters identification of the Perzyna and the Chaboche models for the aluminum alloy at elevated temperature. The additional purpose is comparison of the results for these viscoplastic models. The results have been verified by the numerical simulation of the laboratory tests. The material parameters have been calculated on the basis of the uniaxial tension test. The determination of the...
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Experimental examination of an elastomeric polymer
PublikacjaA new method of repairing damaged structures by filling the cracks with a specially prepared elastomeric polymer mass has been recently proposed. This new and innovative technique, known as the Flexible Joint Method (FJM), is mainly dedicated to masonries and historical objects, where minimum intervention is permitted. The flexible joint bonds the disrupted elements and ensures further safe exploitation of a damaged structure....
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Teaching infrastructure urbanism to aid participatory planning
PublikacjaThe teaching of urban planning at faculties of architecture entails constant tension, caused by issues related to the priorities among urban design (the form) and urban planning (the process). The authors note that knowledge of the relationship between urban design and infrastructure planning, particularly within the realm of public debate within the local community, is of key importance in educating young urban planners. Described...
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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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Interface analysis of compatibilized polymer blends
PublikacjaThis chapter seeks to address the interface location in the compatibilized polymer blends and paves the way for quantitative analysis of interface in terms of interfacial tension and interfacial adhesion to provide support for understanding the relationship between morphology and ultimate properties in the compatibilized polymer blends through the lens of interface. Since understanding and analysis of interfacial phenomena in the...
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Models of Information Systems Integration in CompaniesW : Information Systems Architecture and Technology : IT Models in Management Process
PublikacjaThis work indicates the need for supporting IT organizations with incident and change management IT tools. The work presents tche characteristics of a computer system for the comprehensive management of projects, wich can be used to resolve the issues of version management, releases and incidents.
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Adopting collaborative games into Open Kanban
PublikacjaThe crucial element of any agile project is people. Not surprisingly, principles and values such as "Respect for people", "Communication and Collaboration", "Lead using a team approach", and "Learn and improve continuously" are an integral part of Open Kanban. However, Open Kanban has not provided any tools or techniques to aid the human side of software development. Moreover, as a Lean initiative, it is not as comprehensively...
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Investigation of the aerodynamics of an innovative verticalaxis wind turbine
PublikacjaThis paper presents a preliminary three dimensional analysis of the transient aerodynamic phenomena occurring in the innovative modification of classic Savonius wind turbine. An attempt to explain the increased efficiency of the innovative design in comparison with the traditional solution is undertaken. Several vorticity measures such as enstrophy, absolute helicity and the integral of the velocity gradient tensor second invariant...
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Plasticity of Bead-On-Plate Welds Made with the Use of Stored Flux-Cored Wires for Offshore Applications
PublikacjaExtreme atmospheric conditions in the marine and offshore industry are harmful to engineering materials, especially to welded joints, and may cause degradation of their properties. This article presents the results of research on the plasticity of bead-on-plate welds made using two types of seamless, copper plated flux-cored wires. Before welding, spools with wire were stored for 1 month in two distinct locations with different...
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Bioactive polyurethanes applied as a surgical implants
PublikacjaSynthetic materials are applied in many branches of the industry, i.a. in medicine as a casing of apparatus, elements of artificial organs (hearts, blood vessels), catheters, wound healings, intra aortic balloons, mammary implants to mention but a few. Polymeric material used in such applications must be distinguished by a good biocompatybility. Since many years extensive research are employed to develop a new polymers that can...
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Improving Savonius rotor performance by shaping its blade edges
PublikacjaThe article presents the results of the numerical analysis of the flow inside the Savonius rotor. Particular at-tention has been paid to the vicinity of the blade gap in order to recognise the mechanisms controlling the flow in this area. The conclusions resulting from the analysis made the basis for an attempt to improve Savonius turbine performance via shaping rotor blade edges. The paper presents selected characteristic flow...
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FEM ANALYSIS AND EXPERIMENTAL TESTS OF RIGID RISER HANGING SYSTEM
PublikacjaThe article presents the analysis, project, and experimental examination of an original rigid riser for Coil Tubing Pipes. The principle of riser operation is based on the use of friction forces. The research included the FEM analysis of the designed riser, calculations of the required bolt tensions, and checking the effect of the clamping force on stress distribution in the pipeline. The results of computer simulation were verified...
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Corrigendum to “Fatigue life improvement using low transformation temperature weld material with measurement of residual stress” [Int. J. Fatigue 164 (2022) 107137]
PublikacjaWelding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial...
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Fatigue life improvement using low transformation temperature weld material with measurement of residual stress
PublikacjaWelding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial...
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Novel Approaches of Using of Spirulina Platensis in Natural Rubber Based Composites
PublikacjaThe aim of this work was to investigate the influence of Spirulina (Spirulina platensis) as a natural filler on the curing characterization, morphology and mechanical, thermomechanical and thermal properties of natural rubber (NR) based composites. Spirulina was introduced into NR mixture in amount of 0 phr, 10 phr and 30 phr. The vulcanization process was carried out at the determined process condition by using hydraulic press...
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Development and Research of the Text Messages Semantic Clustering Methodology
PublikacjaThe methodology of semantic clustering analysis of customer’s text-opinions collection is developed. The author's version of the mathematical models of formalization and practical realization of short textual messages semantic clustering procedure is proposed, based on the customer’s text-opinions collection Latent Semantic Analysis knowledge extracting method. An algorithm for semantic clustering of the text-opinions is developed,...
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Thermal and mechanical properties of polyurethanes modified with L-ascorbic acid
PublikacjaIn this study we report the thermal and mechanical properties of polyurethanes modified with ascorbic acid (AA). Ascorbic acid was used as a modifier at concentration of 1 or 2 mass%. The antioxidative properties of AA may improve the biocompatibility of the obtained materials, which were designed for biomedical applications. In this paper we describe characterization of obtained unmodified and ascorbic acid modified polyurethanes...