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Introduction: The coronavirus disease 2019 (COVID-19) is one of the greatest clinical challenges of the last decades. Clinical factors associated with severity of the disease remain unclear. The aim of the study was to characterize Polish patients hospitalized due to COVID-19 and to evaluate potential prognostic factors of severe course of the disease. Material and methods: An observational study was conducted from March to July 2020 in the Pulmonology and Allergology Department of the University Hospital in Kraków, Poland. Consecutive patients with confirmed SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection were enrolled, and data about past medical history, signs and symptoms, laboratory results, imaging studies results, in-hospital management and outcomes was prospectively gathered. Results: The study sample comprised 100 patients at the mean age of 59.2 (SD 16.1) years among whom 63 (63.0%) were male. Among them 10 (10.0%) died, 47 (47%) presented respiratory failure, 15 (15.0%) were transferred to the intensive care unit, 17 (17.0%) developed acute kidney injury, 7 (7.0%) had sepsis and 10 (10.0%) were diagnosed with pulmonary embolism. Multivariable analysis revealed age (OR 1.1; 95% CI 1.01–1.15), body mass index (BMI; OR 1.24; 95% CI 1.01–1.53), modified early warning score (MEWS; OR 3.95; 95% CI 1.48–12), the highest d-dimer value (OR 1.73; 95% CI 1.03–2.9) and lactate dehydrogenase (LDH; OR 1.16; 95% CI 1.03–1.3) to be associated with severe course of COVID-19. Conclusion: This observational study showed that almost half of hospitalized patients with COVID-19 developed respiratory failure in the course of the disease. Increasing age, BMI, MEWS, d-dimer value and LDH concentration were associated with the severity of COVID-19.

Artykuł sygnalizuje problem nieobecności Antoniego Madeja w dziejach literatury polskiej po II wojnie światowej. Za kluczowe dla takiego stanu rzeczy autor tekstu uznaje motywacje wewnętrzne, ale również okoliczności zewnętrzne. Wszystko to pozwala zdefiniować Madeja jako poetę wewnętrznie zaprzeczonego i obiektywnie, ze względu na oficjalny zakaz druku, skazanego na milczenie. Artykuł próbuje przypomnieć dorobek artystyczny Madeja, zachowany w postaci niepublikowanych maszynopisów. Szczególną uwagę poświęca się tu jednemu zbiorowi pisanemu w celi więziennej, noszącemu tytuł Liryki więzienne. Przegląd zawartości tego zbioru ma na celu ukazanie doświadczenia autora, ale też kształtu wrażliwości poety i specyficznej perspektywy rozumienia losu ludzkiego jako takiego.

The dendritic structure and the distribution of the γ′-phase lattice parameter (aγ′) along selected lines of the longitudinal section in a model single-crystalline blade made of CMSX-4® nickel-based superalloy were studied. It was established that there is a correlation between the value of the aγ′ and the predomination of initial or ending fragments of the secondary dendrite arms. It is most noticed for the areas where the dendrite growth conditions are similar to steady. They are located in the center and near the root’s selector extension (SE) area. The correlation has been related to the dendritic segregation mechanism. It was shown that in the single-crystalline blades obtained by the directional crystallization using a spiral selector, the “walls” of the primary dendrite arms that grow at a low angle to the blade axis are created. It was found for the first time that the value of the lattice parameter aγ′ is decreased near such “walls”. Additionally, it was found that competitive growth of the dendrites may occur at a distance of even several millimeters from the bottom surface of the root. The first-time applied X-ray diffraction measurements of aγ′ made in a single-pass along the line allow the analysis of the dendritic segregation in the whole blade cast.

In the present study, the dendrites deflection mechanism from the mold walls were subjected to verification regarding its heat-treated turbine rotor blades. The number of macroscopic low-angle boundaries created on the cross-section of the blades’ airfoil near the tip was experimentally determined and compared to the number of low-angle boundaries calculated from a model based on the dendrites deflection mechanism. Based on the Laue patterns and geometrical parameters of airfoils, the number of low-angle boundaries occurring at the upper part of the blades airfoil after heat treatment was calculated. This number for the analyzed group of blades ranged from 5 to 9.

The γ′ lattice parameter aγ′ and the α angle defining the primary crystal orientation of the single-crystalline cored turbine blades made of CMSX-4 superalloy were measured in the areas located near the selector situated asymmetrically, considering the top view of the blade. The distributions of the aγ′ and the α angle were determined along the lines parallel to the vertical blade axis Z using X-ray diffraction methods. The relations between changes in the aγ′(Z) and α(Z) were analyzed on the Z levels where the shape of the blade’s cross-section changes. For the first time, the local increase in aγ′(Z) was found near the root–airfoil connection level and near certain other root levels, which is related to the change in blade section shapes on such levels. The local extremes in α(Z), representing the dendrite bend, were observed at these levels. The increase in the aγ′(Z) with the local bending of dendrites was discussed concerning the local redistribution of alloying elements and local residual stresses of the γ-dendrites. For the first time, a method of analyzing the local bending of the dendrites was proposed by studying the behavior of the α(Z). The presented results concern the first stage of the research covering areas relatively close to the selector, considering the top view of the blades. The second stage will include the analysis of the areas of the blade localized at a longer distance from the selector.

The areas located near the cooling bores of single-crystalline cored turbine blades made of nickel-based CMSX-4 superalloy were studied. The blades were solidified by the vertical Bridgman technique in the industrial ALD furnace. Longitudinal sections of the blades were studied by Scanning Electron Microscopy, X-ray diffraction topography, X-ray diffraction measurements of the γ′-phase lattice parameter a, and the α angle of the primary crystal orientation. The local changes in α were analyzed in relation to the changes of the dendrite’s growth direction near the cooling bores. It was found that in the area approximately 3 ÷ 4 mm wide around the cooling bores, changes of α and a, both in the blade root and in the airfoil occurred. The local temperature distribution near the cooling bores formed a curved macroscopic solidification front, which caused changes in the chemical composition and, consequently, changes in the a value in a range of 0.002 Å to 0.014 Å. The mechanism of alloying elements segregation by tips of the dendrites on the bent solidification front was proposed. The multi-scale analysis that allows determining a relation between processes proceed both on a millimeter-scale and a micrometric and nanometric scale, was applied in the studies.

Single-crystalline cored CMSX-4 blades obtained at a withdrawal rate of 3 mm/min by the vertical Bridgman method were analyzed. The dendritic structure and crystal orientation near the cooling bores of the blades were studied through Scanning Electron Microscopy, the X-ray diffraction measurements of α and β angular components of the primary crystal orientation, and the γ angular component of the secondary crystal orientation. Additionally, the primary arm spacing (PAS) was studied in areas near and far from the cooling bores. It was found that in the area approximately 3–4 mm wide around the cooling bores, changes occurred in the α, β, and γ angles, as well as in the PAS. The PAS determined for the transverse section of the root and the linear primary arm spacing (LPAS) determined for the longitudinal sections, as well as their relationship, have been defined for the areas located near the cooling bores and those at a distance from them. The vertical temperature gradient of 29.5 K/cm was estimated in the root areas located near the cooling bores based on the PAS values. The value of this gradient was significantly higher compared to the growth chamber operating gradient of 16 K/cm. The two-scale analysis applied in this study allowed for the determination of the relationship between the process of dendrite array creation proceeding on a millimeter scale, which is associated with the local changes in crystal orientation near the cooling bores, and that which proceeds on a scale of tens of millimeters, associated with the changes in crystal orientation in the whole blade cast.

Introduction A significant proportion of patients with COVID‑19 present with a rapidly progressing severe acute respiratory failure. Objectives We aimed to assess the efficacy of high‑flow nasal oxygen (HFNO) therapy in severe acute respiratory failure in the course of COVID‑19 in a noncritical care setting as well as to identify predictors of HFNO failure. Patients and methods This prospective observational study was conducted between March and December 2020. We enrolled all consecutive patients hospitalized with confirmed SARS‑CoV‑2 infection in whom HFNO therapy was used. The primary outcome was death or endotracheal intubation within 30 days from admission. Results Of the 380 patients with COVID‑19 hospitalized at our tertiary center, 116 individuals (30.5%) requiring HFNO due to severe pneumonia were analyzed. The primary outcome occurred in 54 patients (46.6%). The overall 30‑day mortality rates were 30.2% (35 out of 116 patients) in the entire cohort and 64.7% (34 out of 51 patients) among individuals requiring endotracheal intubation. A multivariable analysis revealed that the ROX index (the ratio of oxygen saturation / fraction of inspired oxygen to respiratory rate) below 3.85 measured within the first 12 hours of therapy was related to increased mortality (hazard ratio, 5.86; 95% CI, 3.03-11.35) compared with the ROX index of 4.88 or higher. Conclusions The results of our study suggest that nearly half of patients treated with HFNO due to severe COVID‑19 pneumonia will require mechanical ventilation. The ROX index is a useful tool for predicting HFNO failure in this population.

The author of this article recalls the figure of Antoni Madej, a poet forsaken in contemporary historical and literary reflection. The text discusses Madej’s most important creative achievements during the interwar period, when he published eight poetry collections on various topics, including social ones. However, he was closest to the poetry of personal thoughts in the convention of concise reflective works. This article considers Madej’s attitude to his own work and the problem of reconciling his creative desires with his social aspirations. The analysis of the poet’s life and creative attitude leads the author to conclude that Antoni Madej was a denied poet who tried to overcomethe internal conflict of desires by means of his personal testimony of fragile hope.

The roots of cored single-crystalline turbine blades made of a nickel-based CMSX-4 superalloy were studied. The casts were solidified by the vertical Bridgman method in an industrial ALD furnace using the spiral selector and selector continuer situated asymmetrically in the blade root transverse section. Scanning electron microscopy, the Laue diffraction and X-ray diffraction topography were used to visualize the dendrite array and the local crystal misorientation of the roots. It has been stated that heterogeneity of the dendrite array and creation of low-angle boundaries (LABs) are mostly related to the lateral dendrite branching and rapid growth of the secondary and tertiary dendrites near the surface of the continuer&ndash, root connection. These processes have an unsteady character. Additionally, the influence of the mould walls on the dendrite array heterogeneity was studied. The processes of the lateral growth of the secondary dendrites and competitive longitudinal growth of the tertiary dendrites are discussed and a method of reducing the heterogeneity of the root dendrite array is proposed.

Polish airspace is available on equal terms to all its users. Due to the increasing air traffic airspace structure and the system of airspace, management should constantly improve, taking into account the provisions of international and national conditions. The article looks at issues in the management of airspace in order to increase the efficiency of the use of Polish airspace while maintaining an appropriate level of air traffic safety during flight operations by military and civilian aircraft.

The as-cast single-crystalline turbine blades made of CMSX-4 superalloy were studied. The blades were obtained by the Bridgman technique at a withdrawal rate of 5mm/min. The as-cast samples were prepared by cutting the blade root with a fragment of selector. The dendritic structure of obtained samples was studied by Scanning Electron Microscopy. The crystal orientation and lattice parameters were analyzed by Ω-scan mapping method. Additionally, the X-ray diffraction topography was applied. It was found that the most structural defects are created in the areas where a change in the shape and dimensions of the blades occur. Even minor changes in their geometry and the unevenness of mold walls may also affect the formation of defects.

The variation of the crystal orientation and the dendrite array generated in the root of the single-crystalline (SX) turbine blades made of CMSX-4 superalloy were studied. The blades with an axial orientation of the [001] type were solidified by the industrial Bridgman technique using a spiral selector at a withdrawal rate of 3 mm/min. The analysis of the crystal orientation and dendrite arrangement was carried out using scanning electron microscopy, X-ray diffraction topography, and Laue diffraction. It was found that the lateral growth of such secondary dendrite arms, which are defined as &ldquo, leading&rdquo, and grow in the root at first, is related to the rotation of their crystal lattice, which is the reason for creation of the low-angle boundary (LAB) type defects. The primary crystal orientation of the selector extension (SE) area determines the areas and directions of the lateral growth of the leading arms. Additionally, it was found that in the SE areas of the root, near the connection with the selector, the spatial distribution of the [001]&gamma, &rsquo, crystallographic direction has a complex wave-like character and may be related to the shape of the crystallization front.

The microstructure of as-cast cored turbine blades roots, made of the single-crystal CMSX-4 nickel-based superalloy was investigated. Analysed blades were obtained by directional solidification technique in the industrial ALD Bridgman induction furnace. The investigations of the microstructure of blades roots were performed using SEM and X-ray techniques including diffraction topography with the use of Auleytner method. Characteristic shapes of dendrites with various arrangement were observed on the SEM images taken from the cross-sections, made transversely to the main blades axis. The differences in quality of the structure in particular areas of blades roots were revealed. Based on the results, the influence of cooling bores on blades root structure was analysed and the changes in the distribution and geometry of cooling bores were proposed.

An analysis of the defects in the vicinity of the selector&ndash, root connection plane occurring during the creation of single-crystalline turbine blades made of CMSX-6 Ni-based superalloy was performed. X-ray diffraction topography, scanning electron microscopy, and positron annihilation lifetime spectroscopy were used. Comparing the area of undisturbed axial growth of dendrites to the area of lateral growth concluded that the low-angle boundaries-like (LAB-like) defects were created in the root as a result of unsteady-state lateral growth of some secondary dendrite arms in layers of the root located directly at the selector&ndash, root connection plane. Additional macroscopic low-angle boundaries (LABs) with higher misorientation angles were created as a result of concave curvatures of liquidus isotherm in platform-like regions near selector&ndash, root connections. Two kinds of vacancy-type defects, mono-vacancies and vacancy clusters, were determined in relation to the LABs and LAB-like defects. Only mono-vacancies appeared in the areas of undisturbed axial growth. Reasons for the creation of macroscopic LABs and LAB-like defects, and their relationships with vacancy-type defects were discussed.

The thin-walled airfoil areas of as-cast single-crystalline turbine blades made of CMSX-4 superalloy were studied. The blades were produced by the industrial Bridgman technique at withdrawal rates of 2, 3 and 4 mm/min. The angle between the [001] crystallographic direction and blade axis, related to the primary orientation, was defined by the &Omega, scan X-ray diffraction method at points on the camber line located near the tip of an airfoil and at points of a line located in parallel and near the trailing edge. Additionally, primary crystal orientation was determined by Laue diffraction at the selected points of an airfoil. The influence of mould wall inclination on the primary crystal orientation of the thin-walled areas is discussed. The effect of change in the [001] crystallographic direction, named as &ldquo, force directing&rdquo, was considered with regard to the arrangement of primary dendrite arms in relation to the trailing edge and the camber line. It was stated that when the distance between the mould walls is less than the critical value of about 1.5 mm the &ldquo, increases as the distance between the walls of the mould decreases. The effect may be controlled by selecting an appropriate secondary orientation using a seed crystal in the blade production process. The model of dendrite interaction with the mould walls, including bending and &ldquo, deflection&rdquo, was proposed.

The growth morphology and arrangement of tungsten and β-phase (Al (Fe, Cu)) in Al‑Cu‑Fe‑W alloy were analyzed. The composition of Al65Cu20Fe14W1 (at.%) was used for preparation of ingots containing the icosahedral quasicrystalline phase.The ingots were obtained in a two-stage process. At the first stage the induction melting of the elements and preliminary homogenization by mechanical mixing were carried out. The second stage was realized by vertical Bridgman technique of directional crystallization. The X-ray phase analysis, optical and scanning electron microscopy (SEM) observations and chemical analysis were performed. It was stated that the whiskers of tungsten were irregularly distributed in the volume of ingots. They often form a clump-like agglomerations. The whiskers have different diameters and length. Minimal diameter of the whiskers was about 10 – 100 nm and maximal – several dozen micrometers. The whiskers of tungsten formed a clump-like frames on which the membrane form of β-phase was stretched out or a non-planar oval forms.

The root of single-crystalline turbine blade made of CMSX-4 superalloy were studied. The studied blade was produced by the Bridgman technique in industrial ALD furnace at withdrawal rate of 3 mm/min. The samples for investigations were cut from the blade root parallel to the withdrawal direction. Metallographic sections of longitudinal samples planes were prepared for further investigations. The samples were analysed using scanning electron microscopy and the Laue diffraction studies. The crystal orientations in macro-scale were determined by analysis of the Laue pattern and local crystal orientations were studied by electron backscattered diffraction technique. Morphology of dendrites were examined by analysis of scanning electron microscopy macro-images. Study of subgrain structure was performed by X-ray diffraction topography. The sharp parallel contrast bands, visible on the X-ray topograms, were related with dendrite cores, arranged with the same direction. Additionally, the low angle boundaries were formed in certain samples, visible on the topograms as contrast shifts. Step changes of local crystal orientation in certain areas were observed on the electron backscattered diffraction maps. The electron backscattered diffraction crystal orientation maps were related to the misorientation visualized in topograms.

Single-crystalline superalloy CMSX-4 is studied in the as-cast state and after heat treatment, with material being taken from turbine blade castings. The effect of the heat treatment on the defect structure of the root area near the selector/root connection is emphasized. Multiscale analysis is performed to correlate results obtained by X-ray topography and positron annihilation lifetime spectroscopy (PALS). Electron microscopy observations were also carried out to characterize the inhomogeneity in dendritic structure. The X-ray topography was used to compare defects of the misorientation nature, occurring in as-cast and treated states. The type and concentration of defects before and after heat treatment in different root areas were determined using the PALS method, which enables voids, mono-vacancies, and dislocations to be taken into account. In this way, differences in the concentration of defects caused by heat treatment are rationalized.

The aim of the article is to present the new hybrid technique for ventriculoatrial shunt implantation.Two-and-a-half-year-old boy needed ventriculoatrial shunt implantation due to communicating hydrocephalus and impaired absorptive ability of the peritoneum. Because of a complete occlusion of the right internal jugular vein and critical stenosis of a distal part of the left internal jugular vein, the procedure was performed under fluoroscopy guidance in the catheterisation laboratory equipped with a 3-dimensional single plane angiography machine (Philips Allura--The Netherlands). At the level of critical stenosis of the left jugular vein, it was decided to perform a percutaneous venous balloon angioplasty. This procedure allowed inserting the ventriculoatrial shunt into the right atrium.The whole postoperative period was uneventful. Now, the child is free from symptoms of increased intracranial pressure. The boy has been followed for 9 months. In the control MRI examination, the ventricular system did not change as compared with the previous study.The disadvantage of the hemodynamic technique is a higher dose of X-ray irradiation in comparison to other techniques. The hybrid technique should be reserved only to very complicated cases.

The composites were obtained by the Bridgman method through solidi cation of Al61Cu27Fe12 alloy (numbers indicate at.%). The microstructure of composites with crystal matrix and quasicrystal reinforcement was studied. The crystalline -phase was the matrix and the quasicrystaline i-phase was the reinforcement of obtained composites. The shape and spatial distribution of reinforcement bres were speci ed. Some geometrical relations of the bres arrangement were de ned. Obtained composite samples were subjected to X-ray phase analysis, optical, and scanning electron microscopy observations, chemical microanalysis and the Laue di raction.

W artykule dokonano przeglądu kabin sterowniczych wybranych lokomotyw i stanowisk sterowniczych przed modernizacją, pokazano przebieg prac przy modernizacji kabin lokomotyw z wykorzystaniem modeli 3D kabin lokomotyw przed modernizacją, a po modernizacji pokazano modele 3D zmodernizowanych kabin i nowych stanowisk sterowniczych (konsola, dolna część pulpitu) razem z fotelami oraz zaprezentowano widoki lokomotyw po modernizacji wraz z kabinami i stanowiskami sterowniczymi po modernizacji. Praca dotycząca modernizacji kabin została wykonana w ramach projektu rozwojowego NR 10-0062-10/2011 pt. „Lokomotywy manewrowe z hybrydowym układem napędowym z wykorzystaniem wysokowydajnych zasobników energii” i sfinansowana przez NCBR.

The purpose of the article is the presentation of the results of research aiming at the assessment of the level of social competences and locus of control of teenage mothers and pregnant teens placed at the correctional institutions as the variables significantly determining the way of functioning in the society (more broadly - functioning in the environment). Social skills are essential in order to manage oneself properly in the context of the effectiveness of actions undertaken by a person in social situations. The most common indicators of this effectiveness are: the achievement of an individual's own goals and the compliance of their behaviour with social expectations. In other words, the essence of social skills is the ability to reconcile one's own interests with the interests of society, and - following this, to deal with the differences between individual and socially important goals (Oppenheimer 1989). The effectiveness of social training that an individual is subject to throughout life is determined by his/her intellectual capabilities. While intensity and type - temperament and personality traits (e.g. extra-introversion, reactivity - activity, anxiety, impulsiveness - thoughtfulness, cognitive curiosity - caution) (Matczak 2001; Smolka 2008). Environmental conditions, training and therapeutic influences, both intentional (including educational), and unintentional also play a large role, as do - what seems to be extremely important in the described situation - normative influences of one's own socio-environmental enclaves (local communities with their internal standards, codes and rituals) 1 .

The composites of Al-Cu-Fe alloys with fibrous reinforcement, containing quasicrystals, e.i. crystal-quasicrystal composites (CQ composites) were studied. The composites were obtained in situ by the Bridgman method. The plate-like samples were studied by tensile test performed up to rupture. Tensile fracture surface of composite and reinforcement fibers were investigated. The role of voids on the fracture morphology and the reason of its formation were discussed.

The microstructure of Al65Cu20Fe14 (numbers indicate at.%) alloy doped with 1 at.% of W was studied. The selected alloy composition should allow to obtain the quasicrystalline icosahedral phase after solidification process. The bulk samples were obtained in two stages. At first, the synthesis of alloy through premelting of component elements in induction furnace and then, the directional solidification by the Bridgman method were performed. The morphology of selected areas of the samples were studied using Scanning Electron Microscope equipped with energy dispersive X-ray spectroscope, which was used to examine chemical compositions of each analysed areas. Additionally the X-ray powder diffraction was used to identify the phases present in the alloys. It was stated that the filaments of tungsten were present in the alloys. The filaments have thickness ranged from 0.01 to 2.5 μm. As a result of investigation, the arrangement of filaments in the material was determined.

Composite based on Al–Cu–Co alloy obtained by directional solidification, were characterized. The quasicrystalline decagonal D phase of Al64Cu20Co16 was the reinforcement and the singlecrystalline tetragonal T phase of Al72Cu27Co1 was the matrix of the composite. The phases were identified by powder X-ray diffraction (XRD). The composite was analysed by light optical microscope and electron microscopes. The SEM and TEM techniques were used. Additionally the Laue method was used. The results of the study showed that the reinforcement has a form of parallel fibres of 20-40 μm diameter. Quasicrystal structure of fibres contained the phason strain. The quasicrystalline phase in the form of decagonal columns was also present inside composite pores.

The microstructure of Co0.75Ni0.25Si2solid solution, obtained by two different techniques was studied. The solidification processes were conducted using Bridgman and Czochralski methods. The processes were conducted under atmospheric pressure and in the helium atmosphere. Various pulling down (Bridgman method) and pulling up (Czochralski method) rates were applied for ingots and boules preparation. The obtained Co0.75Ni0.25Si2ingots and boules were subjected to the metallographic observations and chemical microanalysis, mainly used Scanning Electron Microscopy techniques. They were studied using X-ray phase analysis too. Comparing the investigation results it was found that the ingots obtained by the Bridgman method and boules obtained by the Czochralski method were single crystalline. The boules, obtained using the Czochralski method, possess better structural quality than ingots obtained by the Bridgman method.

Microstructure of terminal area of Al65Cu32.9Co2.1ingots (numbers indicate at.%), obtained via directional solidification was studied. Scanning Electron Microscopy, Transmission Electron Microscopy and X-ray powder diffraction were applied. Point microanalysis by Scanning Electron Microscope was used for examination of chemical compositions of alloy phases. It was found that tetragonal θ phase of Al2Cu stoichiometric formula was the dominate phase (matrix). Additionally the alloy contained orthogonal set of nanofibres of Al7Cu2Co T phase with the average diameter of 50-500 nm and oval areas of hexagonal Al3(Cu,Co)2H-phase, surrounded by monoclinic AlCu η1phase rim. Inside some areas of H-phase cores of decagonal quasicrystalline D phase were observed.

Morphological details and chemical composition of whisker-like crystals (W-LCs) were studied. The W-LCs were grown on Al2O3 substrate as a result of evaporation of Al65Cu26Co9 alloy. Morphologically diverse W-LCs formed groups in the shape of brushes. The two-phase nature of W-LCs was revealed. The W-LCs consisted of an intermetallic on the Al matrix forming the core and of an external oxide shell of developed faces. The chemical composition of the core and the shell corresponded roughly to the stoichiometric formula Al3Cu and AlO accordingly. Additionally the core contained small amounts of cobalt and oxygen and the shell-copper and cobalt. The growth mechanism of W-LCs was proposed based on their morphological details and chemical compositions. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Fibre-reinforced composites were produced by the modification of the static horizontal Bridgman method. The single-crystalline composite matrix consisted of the tetragonal T phase (Al72Cu27Co1). Decagonal quasi-crystal D phase (Al64Cu20Co16) was the reinforcement in the form of fibres parallel to the solidification direction. These fibres were surrounded by the tetragonal Θ phase (Al66Cu31Co3). The composite specimens in the shape of plates were studied by tensile tests and X-ray topography. The specimens deformed up to rupture and, from the X-ray topographs, the dependence of the composite structure defects on deformation was examined. It was found that the rupture of specimens is related to low-angle boundaries created during deformation. The influence of defects on the strength of the composites is discussed. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The microstructure of a composite containing a quasicrystal phase, i.e. so-called crystal–quasicrystal (CQ) composite, was studied. The CQ composite was obtained by the Bridgman method via solidification of Al61Cu27Fe12 alloy (numbers indicate at%). The process was conducted at a pull out rate of v = 0.07 mm/min. The average temperature gradient in the heating zone was 43 K/cm. The composite matrix consisted of cubic β phase Al(Fe, Cu), with reinforcement of λ-phase rod-shaped fibres surrounded by a quasicrystal icosahedral ψ phase, which also existed in the fibre core. The fibres were rhomboidal in cross-section. The composite was studied using X-ray and electron diffraction, light-optical and scanning electron microscopy (SEM), X-ray topography and Laue diffraction.

Crystal-quasicrystal columnar composites (CQ composites) of Al Cu Fe alloy subject to tensile strain at room temperature were studied by the reflective X ray topography. In those composites singlecrystalline β phase occurred as the matrix and rods consisting of quasicrystalline ψ phase and crystalline λ phase as the reinforcement. X-ray topograms of plate like composite specimens were obtained using reflexes of singlecrystalline matrix. It has been found that at strains ε up to 0.33% in a linear range of stress strain σ(ε) relationship the topograms remain unchanged. Instead, at ε higher than 0.33% significant contract changes have been observed in some areas of topograms. It has been determined that at ε higher than 0.33% the components of misorientation angle of those areas increase with increasing strain. Methods of powder phase analysis, metallographic examinations by means of optical microscopy methods and X-ray diffraction topography methods were used.

The columnar composites obtained “in situ” through solidification of Al61Cu27Fe12 alloy by the Bridgman method were studied. It has been verified that the matrix consisted of cubic single crystal β phase and the reinforcement of icosahedral quasicrystal ψ phase and monoclinic crystal λ phase, which have the form of rods. This kind of composites will be named the Al-Cu-Fe crystal-quasicrystal (CQ) composites. The effect of heating from a temperature of about 100°C to about 650°C on the stress-strain relationships σ(ε) of parallel samples was studied. Additionally, the σ(ε) relationship was defined in cyclic load-unload tests at different temperatures. The composites were examined by powder X-ray diffraction and scanning electron microscope.

The single crystal turbine blades made of CMSX-4 nickel-based superalloy were studied. The turbine blades were obtained by the Bridgman technique with withdrawal rate of 5 mm/min. The samples, cut-off from root part of blades and containing the fragment of the selector, were studied. The effect of selector geometry on the dendrites growth and defects formation in the selector-root area of the blade were analyzed. The Laue diffraction, scanning electron microscopy, and X-ray diffraction topography were applied. It was found that, during crystallization of the selector, the dendrite cores, after reaching the surface of mould, may bend, if the angle between dendrite cores and the mould surface was equal to 12 . When the angle was equal to 24 the growth of dendrites has been stopped. It can be stated that the defects, which appeared in the selector were inherited by the root part.

The airfoils of single-crystalline turbine blades were studied. The blades made of industrial CMSX-4 superalloy were obtained by the Bridgman technique. Five different withdrawal rates (1–5 mm/min) were used. Series of as-cast samples were prepared by cutting the airfoils at different distances from the blade root. The metallographic sections, prepared for each cutting planes, were subjected to scanning electron microscopy observations and Laue diffraction studies. Macrostructure images of whole area of airfoil cross-sections were obtained by stitching several obtained SEM images. Morphology of dendrites in different area of cross-sections were analysed. The crystal orientation of each sample were determined by analysis of Laue pattern. It was found that the morphology of dendrites changes in the area, where the dendrite growth is limited by inclined mould walls.

The main goal of paper was obtaining of solid solution Co1-xFexSi2 crystals from liquid phase by Bridgman method. There are presented features and quality parameters of obtained ingots. It was found that the substitutional solid solution Co1-xFexSi2 crystals can be obtained only for x = 1at.% Fe.

The subject of the study is the composite material of CoSi2-Si eutectic composition. The influence of crystallization speed on microstructure was examined. The ingots were obtained using Bridgman method. Three different pulling down speeds of crucibles with melted charges were applied. The prepared samples were subjected to metallographic, X-ray, TEM techniques and mechanical examinations in order to characterize the properties of the studied composite material. It was shown that the favourable crucible pulling down speed to obtain CoSi2-Si fibrous eutectic microstructure was 3mm/h.

Objective: The authors intended to evaluate the application of neuroendoscopic techniques for the treatment of arachnoid cysts in children and compare it with other operative methods. Methods: The analysis covered the results of treatment of 44 children with arachnoid cysts who were subjected to neuroendoscopic procedures and 62 patients who underwent other operations. Results: The neuroendoscopic treatment of arachnoid cysts was very effective because of low rate of reoperative treatment (six out of 44 patients), no need to change the operative method (40 effective out of total 44 operative procedures), and low rate of persistent worsening (none of 44 patients worsened). Conclusions: Summing up all the mentioned aspects of neuroendoscopic techniques, the neuroendoscopic techniques were the most suitable operative procedures in the treatment of arachnoid cysts in the presented group of patients, providing that the connection between the lumen of the arachnoid cyst and the cerebrospinal fluid cisterns was of good quality.