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Nickel-copper alloys are commonly used in highly corrosive conditions where strength is required. Typical applications are in the marine sector, petrochemical industry, or energy facilities such as chemical tubes, pumps, heat exchangers and superheated steam systems. This paper compares the microstructure and mechanical properties of a cast alloy with a 3D printed alloy processed via a laser powder bed fusion (LPBF) technique. Small cylindrical specimens were used for tensile tests at room temperature (RT) and elevated temperatures up to 750 °C in air. The tensile stress-strain response was determined for both types of materials. At RT, LPBF material has a higher yield strength and ultimate tensile strength than a cast alloy. At elevated temperatures, the strength of both variants is comparable. However, the fracture elongation of the LPBF material is significantly lower over the entire range of investigated temperatures. Fracture surfaces and polished sections parallel to the specimen axis were investigated to compare the microstructure and damage mechanisms of the nickel-coper alloy 400 prepared by conventional casting and via LPBF.

The aim of this study is to conduct an experiment on the effects of Instagram usage reduction on psychological well-being.

Characteristic features of fatigue damage of 316L austenitic stainless steel cyclically strained axially in tension-compression, reversed torsion and combined axial-torsional mode were studied. All loading modes resulted in the formation of persistent slip markings (PSMs). Predominantly one slip system was activated in the case of axial and torsional loading while at biaxial loading, activation of several slip systems was involved. PSMs acted as sites of multiple fatigue crack initiation. The path of subsequent crack growth at a macroscopic scale differed considerably in dependence on loading mode and applied amplitude. The hardening-softening curves and fatigue life curves were evaluated and results were compared and discussed in terms of the type of applied loading.

This article deals with the effect of periodically acting liquid droplets on the polished surfaces of AISI 316L stainless steel and Ti6Al4V titanium alloy. These materials were exposed to a pulsating water jet produced using an ultrasonic sonotrode with an oscillation frequency of 21 kHz placed in a pressure chamber. The only variable in the experiments was the time for which the materials were exposed to water droplets, i.e., the number of impingements; the other parameters were kept constant. We chose a low number of impingements to study the incubation stages of the deformation caused by the pulsating water jet. The surfaces of the specimens were studied using (1) confocal microscopy for characterizing the surface profile induced by the water jet, (2) scanning electron microscopy for detailed surface observation, and (3) transmission electron microscopy for detecting the changes in the near-surface microstructure. The surface described by the height of the primary profile of the surface increased with the number of impingements, and was substantially more intense in the austenitic steel than in the Ti alloy. Irregular surface depressions, slip lines, and short cracks were observed in the Ti alloy, whereas pronounced straight slip bands formed in the austenitic steel. The dislocation density near the surface was measured quantitatively, reaching high values of the order of 1014 m−2 in the austenitic steel and even higher values (up to 3 × 1015 m−2) in the Ti alloy. The origins of the mentioned surface features differed in the two materials: an intense dislocation slip on parallel slip planes for the Ti alloy and mechanical twinning combined with dislocation slip for the austenitic steel.

Effect of the pulsating water jet on the plastic deformations of surface of Ti6Al4V was examined. Existing research papers investigating the interaction of Ti6Al4V with pulsating water and water impact are focused on culmination erosion stage of the impacted area. In this article, the initial stages of erosion were studied in term of the increasing but relatively low number of impingement on the microplastic deformation. The number of impacts varied from 1050 to 63000 impacts. The PWJ was positioned at the standoff distance of 5.5 mm above material surface. The aim of this research was to study the influence of early erosion stage, consisting of plastic deformation and material removal in preferential sites, on the material structure. The determination of early erosion stages can be used for selecting the conditions of PWJ leading to the surface strengthening, analogical to shot peening. Sites with significance to the surface strengthening were observed and discussed. Interphase boundaries and other structural characteristic play significant role in the earliest stages of erosion.

In this study, the occurrence of lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) in the environment of the Moravian Library in Brno, the second largest library in Czechia, was in focus. The materials of interest were airborne particles, dust originating from books, and also book pages. Total suspended particles (TSP) were sampled in different areas of the library, including the reading room, the book depository, and an external book warehouse. Samples of dusts were obtained from the book-cleaning system, and, moreover, some pages taken from old books were also analyzed. Samples were microwave-digested and analyzed using graphite furnace high-resolution continuum source AAS (HR-CS GF-AAS). During the analysis, possibilities of the signal intensity modulation of the HR-CS technique were demonstrated and employed in order to determine Zn, an element which is rarely determined by GF-AAS. The median TSP concentrations (in ng/m3) were as follows: Pb, 4.4; Cd, 0.07; Cu, 2.6; and Zn, 20.9. Such concentrations are safely below allowed limits. Contents of Pb determined in dust samples and book pages were slightly higher (up to 707 and 38 mg/kg, respectively) than the usually reported values. However, none of these results indicate a potential risk to library staff or readers.

The paper describes the interaction between pulsating water jet and surface of three different metals: 316L stainless steel, 6068 Al alloy and Ti6Al4V Ti alloy. The pulsating water jet is formed by using the ultrasonic sonotrode to the pressurized acoustic water chamber. It appears that the shape of the resulting water jet differs at various distances from the nozzle and the state of the surface of tested materials treated by the jet at various standoff distances differs very substantially. Moreover, the three materials are exposed to pulsating water jet at different standoff distances and results are discussed in terms of the capacity to absorb plastic deformation. As expected, at optimal standoff distance, the deepest eroded path appears in the Al alloy and the most resistant material is the Ti alloy.

The disintegration of the material by PWJ technology depends upon many technological parameters of the equipment and particular material properties. This paper deals with the erosive effects of PWJ on the polished surfaces of metallic materials such as titanium (Ti6Al4V) and aluminium (ENAW1050AH24) alloy. The evaluation and comparison of the extent of disintegration are done on the basis of the erosion depth achieved. The nozzle movement over the material followed an ascending equidistant trajectory from z = 15 to 41 mm with a vertical step height of 2 mm. PWJ transitions over the material were performed with a sonotrode frequency f = 20.19 kHz, liquid pressure p = 40 MPa and a feed rate v = 0.25 mm.s−1. The depth value of the grooves formed was then measured using a MicroProf FRT contactless measuring device and evaluated in the SPIP 6.7.8 software. For aluminium sample, the deepest average depth value is h = 1583.2 µm (z = 29 mm), while the titanium material has eroded to a much smaller depth, h = 283.2 µm (z = 31 mm). By comparing the achieved hydrodynamic effects of PWJ on titanium and aluminium, significant differences in the depth of erosion and its course can be observed due to the different mechanical properties of the materials.

The present study is focused on the evolution of microstructure of silicon steel (Fe-Si 6 wt%) after treatment by pulsating water jet (PWJ). The various stages of erosion by pulsating water jet have been studied. The initial damage shows formation of depressions and isolates erosion pits. Repeated passing of water initialized further pit formation and coalescence of pits to craters. During this stages small cracks formation was observed. The repeated passing of water induced deepening of the craters and material removal. The PWJ caused plastic deformation and increase of values of hardness of the subsurface region. The cleavage fracture was present on contained eroded surface.

This paper describes and applies a methodology to determine the elastic properties of freestanding thin membranes by means of a bulge test and a numerical approach. The numerical procedure is based on the combination of two standard methods i.e. finite element analysis and classical analytical solutions to calculate elastic properties of thin films. Bulge tests were conducted on silicon nitride (Si3N4) monolayer of 2 × 2 mm (square) and 3.5 × 1.5mm (rectangular) membranes with the aim to determine elastics properties (Young's modulus (E) and Poison's ratio (v)) that define the load-deflection curves of both membranes. With this purpose, an error function was constructed for each membrane which involved finite element solutions, analytical solutions and experimental measurements. Error functions were found and minimized by mapping a set of elastic parameters for the two membranes (square and rectangular). A unique solution was determined in the intersection of both linear approximations, obtaining 236 GPa for E and 0.264 for v. It is well known that in a traditional bulge test analysis only one of both biaxial modulus can be determined and not a combination of E and v. Numerical results show that calculated load-deflection curves agree well with the measurements obtained for both square and rectangular membranes experimentally. The proposed methodology is only applicable in thin films with elastic behavior, however generalization for more complicated geometries is possible.

In the present paper, the authors have investigated the microstructural aspects of recrystallization of new ODS alloy (Fe-14Cr-10Al-4Y2O3) consolidated by hot rotary swaging. Microstructural characterization of samples was performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD). Insight of mechanical properties was performed by Vickers hardness testing and measurement of Young's modulus. A thorough analysis of microstructure concerning grains, oxide particles and dislocations was performed for two states of the material, i.e. in the as-received state after rotary swaging exhibiting the ultra-fine-grained microstructure and in the state after annealing provoking the desirable coarse-grained structure. Different conditions of rotary swaging followed by the same annealing conditions induced different structures, either coarse-grained or bimodal when secondary recrystallization did not happen in the entire sample's volume. The hardness measurements revealed no significant difference between the coarse-grained and the bimodal microstructures, however, the coarse-grained material exhibited systematically higher values of the temperature-dependent Young's modulus in comparison with the bimodal counterpart. Detailed microscopic analysis of the material helped to clarify and discuss the measured properties of the newly developed ODS alloy.

This paper addresses the important issue of the description of short fatigue crack behaviour. It is typical for these cracks that they propagate under large scale yielding conditions at the crack tip, which means that the non-linear fracture mechanics has to be applied. This paper presents results of experiments designed to measure the short crack growth rates in five different materials – 316L steel, Eurofer 97 steel, ODS Eurofer steel, Duplex 2205 steel and Al 6082 alloy. The crack growth rates of these materials are described using different fracture mechanics parameters – the stress intensity factor, the J-integral and the plastic part of the J-integral. These approaches are evaluated and compared. The comparison revealed that the plastic part of the J-integral is the parameter governing the short crack growth rate in large scale yielding conditions. Moreover, crack growth rate data from all the tested materials measured at various loading levels lies on a unique curve. This remarkable observation suggests that the crack growth rate is determined by the extent of energy spent to plastic deformation, irrespective of the other materials properties.

The aim of this work was to activate the surface of dyed natural leather using a diffuse ambient air plasma treatment. The plasma was generated by the so-called diffuse coplanar surface barrier discharge (DCSBD). It was observed that a 10 s plasma treatment time is enough to decrease the water contact angle from 85° to 45°. Improvement of wettability is important for gluing of dyed leather and better adhesion of glue to leather parts. XPS study indicated that the percentage of oxygen-containing bonds responsible for hydrophilicity is significantly increased by the plasma treatment. Influence of the plasma treatment on mechanical properties of dyed leather was evaluated using tensile strength measurement and no significant changes in the surface morphology and mechanical properties were observed. The results indicate that the DCSBD technique can provide high throughput, technical simplicity and economy required by the leather industry.

Pure polycrystalline copper has been subjected to cyclic loading with frequencies from 4 Hz to 20 kHz. With increasing frequency, the S-N curve was shifted to a higher number of cycles to fracture. Quasi-static and dynamic tensile tests were performed to identify the strain rate sensitivity corresponding to the increase of the cyclic frequency in order to explain the shift of the S-N curve with the frequency. Surface relief evolution has been studied in specimens cycled with various stress amplitudes and frequencies. Scanning electron microscopy inspection of the surface and the perpendicular cuts produced by focused ion beam sectioning allowed characterizing the surface relief and internal structure of the individual specimens subjected to cycling. Characteristic types of slip bands were found. In all cases, cavities formed in or around the primary slip plane below the slip markings. Focused ion beam slicing and image recording with subsequent 3D reconstruction allowed obtaining the distribution of cavities below the slip markings. A close relation was established between the distribution of cavities and resulting surface relief. Formation of cavities in the slip band led to the development of extrusions and in some cases also to tiny intrusions. Both rough surface relief and the cavity distribution below the surface along the slip plane contributed to the initiation of the fatigue cracks. Localized cyclic straining with a high strain rate has been analyzed in terms of vacancy generation within the slip band leading to cavity formation.

The research deals with plasma treatment of acrylonitrile butadiene styrene plastic (ABS). The plastic was treated with Diffuse Coplanar Surface Barrier Discharge (DCSBD) and Gliding arc at atmospheric pressure. ABS was chosen because of its low price, wide use in industry. Samples were analyzed with contact angle measurement and the surface energy was determined as well. The results show that only a few seconds of plasma treatment can cause relatively large wettability change.

Electron beam lithography was used to fabricate platinum μ-contacts over tungsten oxide nanorods formed on a mica substrate. This made possible the measurement of sensorial response of these self-assembled tungsten oxide nanorods to hydrogen gas for the first time. The nanorods were prepared by thermal evaporation from an oxide source. Consequently, two types of conductometric sensors were assembled: a) percolating network of nanorods and b) set of individually contacted WO3 nanorods. The preparation procedures are described in detail and the comparison of response of both types of assemblies is given. The first sensorial measurements revealed a good response of the b) type of sensor and the minimum repeatedly detected concentration of H2 was 50 ppm.

Two γ-based TiAl alloys with 7 at.% of Nb, alloyed with 2 at.% Mo and 0.5 at.% C, were studied. A heat treatment leading to very fine lamellar microstructure was applied on both alloys. Microstructure after the heat treatment was described and mechanical properties including fatigue behaviour were measured. The as-received material alloyed with C possesses high strength and very limited ductility, especially at RT. After application of selected heat treatment it becomes even more brittle; therefore, this process could be considered as not appropriate for this alloy. On the contrary, in the case of Mo alloyed material, both strength and ductility are improved by the heat treatment at RT and usual working temperature (~750 °C). Presence of the β phase is responsible for this effect. The selected heat treatment thus can be an alternative for this alloy to other thermomechanical treatments as high temperature forging.

Aluminium based material having chemical composition of Al 93 Fe 3 Ti 2 Cr 2 (at.%) was prepared by hot extrusion of gas atomised powder. Microstructure consisting of aluminium matrix and icosahedral quasicrystalline particles was investigated by scanning and transmission electron microscopy a X-ray spectroscopy. Size, distribution and inner structure of quasicrystalline particles were determined. When quasicrystalline particles having submicron size were present in the microstructure together with fine-grained aluminium matrix, it resulted in enhancement of mechanical properties. Fatigue experiments were performed in load controlled regime with positive mean stress and fatigue life data for this quasicrystalline material were compared with similar results for commercially available aluminium alloys. Longer fatigue life together with higher fatigue strength reaching value of 350 MPa was observed. It is approx. 100 MPa higher than for commercially produced coarse-grained aluminium alloys. Fractographic observations revealed presence of fish eye fracture patterns and validity of weakest link fracture mechanism acting in this type of material under investigation.

Effects of alloying elements (i.e., variable content of Mo and C) on the microstructure and mechanical properties of five types of experimental material based on TiAl alloy containing 7 at.% Nb were investigated. Mechanical properties (tensile, compression and fatigue) at room and at elevated temperatures were evaluated. Addition of Mo and/or C resulted in different phase compositions and three typical microstructures. To judge the effect of alloying on the microstructure the comparison with reference TiAl alloy with 7 at.% Nb without C and Mo addition was used. Evaluation of mechanical properties of individual alloys revealed two most promising variants: (i) alloy with 2 at.% Mo containing β phase, having mixed microstructure and exhibiting the highest ductility, (ii) alloy with 0.5 at.% C having nearly lamellar microstructure, enhanced amount of α 2 phase, without β phase and exhibiting the highest strength. No positive effect of combined Mo and C addition on mechanical properties was identified. Fractographic observations revealed that the major fracture mode in all alloys was trans -lamellar. Inter-lamellar fracture was observed occasionally and mainly in C containing alloys.

The present study is focused on surface modification by the shock wave and its impact on the microstructure of silicon steel (Fe-Si 6wt %). The shock waves were created by two different methods - by pulsating water jet (PWJ) and by laser shock peening (LSP). Although both methods create shock waves, impact on the microstructure of the sample was different. The sample after PWJ treatment was eroded and contained cavities and tunnels. The surface of samples after LSP has been partly oxidized and re-melted. Cross-section examination of both samples shows plastic deformation, slips and twins, in the microstructure of material. Both methods increased of values of hardness in the subsurface region.

The very recently developed coarse-grained new-generation oxide dispersion strengthened (ODS) alloys containing 5 vol.% homogeneously distributed yttrium nano-precipitates seems to be a promising oxidation-resistant structural material for applications at temperatures above 1000 &deg, C. The primary aim of the present paper is the introduction of the new-generation oxide dispersion strengthened (ODS) alloy and the first testing of its high temperature fatigue properties at 800 &deg, C, concurrently demonstrating a novel and very efficient methodology by using an incremental fatigue step test. The successful application of the methodology motivates the authors to test the fatigue properties of new generation ODS alloys at 1000&ndash, 1200 &deg, C in the near future.

In this study, the effect of the heat-treatment was investigated on five different γ-TiAl compositions alloyed with 7 at.% of Nb and varying content of Mo and C. Mechanical properties of as-received and heat-treated alloys were assessed using tensile and symmetrical tension-compression cyclic loading at room temperature and 750 °C. Scanning electron microscopy, electron back-scatter and X-ray powder diffraction, as well as high-resolution scanning transmission electron microscopy, were used to characterize microstructural changes induced by the heat-treatments. Modification of lamellar substructure in terms of a significant decrease of lamellar spacing directly affects the mobility of dislocations. Together with the change in the phase composition of the alloys, it is the key mechanism leading to the improvement of the ultimate tensile stress, fracture plastic strain as well as higher cyclic strength. It also increases the cumulative plastic strain in cyclic loading both at ambient and elevated temperatures.

Low cycle fatigue (LCF) behaviour of metastable austenitic 301LN stainless steel with different grain sizes – coarse-grained (13 μm), fine-grained (1.4 μm) and ultrafine-grained (0.6 μm) – produced by reversion annealing after prior cold rolling was investigated. Fully symmetrical LCF tests with constant total strain amplitudes of 0.5% and 0.6% were performed at room temperature with a low constant strain rate of 2×10-3 s-1. Microstructural changes in different positions within the gauge part of the specimens were examined by optical microscopy (polarized light) and electron backscatter diffraction (EBSD) technique; for quantitative assessment of the volume fraction of deformation induced martensite (DIM) a Feritscope FMP 30 was adopted. The cyclic stress-strain response and specific changes of hysteresis loop shapes in the very early stage of cycling are confronted with the character of DIM formation and its distribution in the whole volume of the material. A possible effect of strain rate (frequency of cycling) on the destabilization of austenitic structure during cyclic straining of materials with different grain sizes is highlighted.

This study shows a methodology to estimate mechanical parameters of thin films by means of a bulge test and a numerical approach. The methodology is based on the combination of finite element analysis with a classical analytical method. Finite element modelling was conducted for monolayer (Si3N4) membranes of 2x2mm with the aim to approximate both the load-deflection curves experimentally measured and the classical load-deflection analytical model. Error functions were constructed and minimized to delimit a coupled solution space between Young’s modulus and Poison’s ratio. In a traditional bulge test analysis only one of the elastic properties can be determined due to that there is not unique solution in the estimations of these parameters. However, both elastic parameters were determined through the proposed numerical procedure which compares the deformed surfaces for a specific set of optimal elastic parameters computed. Results show that the estimated elastic properties agree with corresponding values determined by other methods in the literature.

Nickel-based cast IN 738LC superalloy has been cycled at increasing strain amplitudes at room temperature and at 800 °C. Hysteresis loops were analyzed using general statistical theory of the hysteresis loop. Dislocation structures of specimens cycled at these two temperatures were studied. They revealed localization of the cyclic plastic strain in the thin bands which are rich in dislocations. The analysis of the loop shapes yields effective stresses of the matrix and of the precipitates and the probability density function of the critical internal stresses at both temperatures. It allows to find the sources of the high cyclic stress.

Cyclic strain controlled tests with blocks of stepwise increasing strain amplitudes were applied to cylindrical specimens of cast Inconel 738LC superalloy at 23 and 800 °C in laboratory atmosphere. Cyclic hardening/softening curves and shortened cyclic stress–strain curves were obtained at both temperatures. The hysteresis loops were analyzed using generalized statistical theory of the hysteresis loop. The second derivative of the half-loop exhibits three domains. The initial drop represents the plastic strain relaxation under decreasing effective stress and two peaks correspond to the probability density distribution of the internal critical stresses in matrix ( γ phase) and γ ′ phase respectively. Localized cyclic straining was identified using dislocation structure of PSBs and surface relief corresponding to PSMs. Weibull probability density function was fitted to individual peaks and effective stress component and probability density distributions of the internal critical stresses were quantitatively evaluated.

Ternary TiAl alloy with 8 at.% Nb and lamellar microstructure is subjected to low cycle fatigue tests at temperatures ranging from room temperature to 800 °C. The aim of the study is to find limit conditions when the microstructure is still stable and to study mechanisms of microstructural degradation when this limit is exceeded. Up to 750 °C, no cyclic softening or hardening is observed and cyclic stress-strain curve follows the tensile curve. Cyclic softening is characteristic for 800 °C. The TEM observation did not reveal any substantial changes in the microstructure due to the cycling up to 700°C. The lamellar structure is altered by cyclic straining at 750 °C and, to a higher extent, at 800°C. In specimens cycled to fracture at 800 °C, the domains without lamellar structure cover about 10% of volume and are almost dislocation free. The destruction of lamellar microstructure is the reason for the marked cyclic softening at 800 °C.

Austenitic stainless 316L steel in cold worked condition was subjected to torsional cyclic loading with equivalent strain amplitudes of 0.3% and 0.4% and multiaxial (in-phase and out-of-phase) cyclic loading with equivalent strain amplitude of 0.35% at room temperature. Cyclic plastic response has been measured and analyzed. Internal structure in the as-received state was compared with the deformation microstructures that developed during cyclic straining with various strain histories. In all three investigated cases the volumes with dislocation structures corresponding to cyclic strain localization (persistent slip bands, irregular wall and channel structures) were found. In addition, also islands of deformation induced α′-martensite were observed. Transmission electron microscopy, selected area electron diffraction and ferritscope measurements allowed to estimate the fraction and distribution of α′-martensite islands. The shape of fatigue hardening/softening curves has been discussed in relation with the localization of cyclic plastic strain in the low energy dislocation structures and its blockade by the islands of α′-martensite.

The glycaemic index (GI) is a measure of the food power to raise plasma glucose (PG) concentration after a meal. For its determination, classical methods register the development of glucose concentration in capillary plasma or whole blood. The aim of this prospective open-label trial was to compare the GI of selected foods obtained by means of the Continuous Glucose Monitoring System (CGMS) (Minimed Medtronic, Northridge, USA) which has not been applied for this purpose until now, with the respective GI determined by a conventional method using the Glucometer Advance System (GAS) (Hypoguard, Woodbridge, United Kingdom), and to assess the advantages of each approach. Methods Portions of tested foods containing 50 g of carbohydrates were eaten for breakfast and for dinner after 10 and 4 h fast, respectively, by 20 healthy volunteers. Using GAS, PG-curves were constructed from 9 PG values at time 0, 15, 30, 45, 60, 75, 90, 105 and 120 min after the meal, and, using CGMS, from 25 values of interstitial fluid glucose concentration (ISFG) stored within 120 min in 5-minute intervals in CGMS memory. The GI was calculated (for GAS and CGMS separately) by dividing the incremental area under the curve for the tested food by the average area of 3 tests performed with the standard. Having excluded tests with missing glucose values, there remained 285 GAS- and 290 CGMS tests for further analysis. In each volunteer, each food was tested 3 times within one week so that 1 to 3 GI's were obtained and averaged. The GI for each tested food was calculated as the mean from the respective average GI's of 20 volunteers. The GI-variability was assessed according to the respective SD. The preference of GAS vs. CGMS in the persons tested was explored by means of a questionnaire. MS Excel and the statistical program SPSS v. 10.1 were used to analyze the data. Results The GI values (mean +/- SD) measured by GAS/CGMS were for dark chocolate 43.6 +/- 22.13 %/44.0 +/- 21.71 % (p > 0.01); for apple baby food 46.1 +/- 21.38 %/53.8 +/- 37.69 % (p > 0.01); for puffed rice squares 76.5 +/- 20.24 %/76.9 +/- 27.62 % (p > 0.01); for yogurt 43.2 +/- 20.17 %/37.7 +/- 21.55 % (p > 0.01). The GI's of dark chocolate, apple baby food and yogurt, determined by either method, were significantly lower than the GI of puffed rice squares (p Conclusions No significant difference could be seen between the GI's determined by conventional method (GAS) and by CGMS (p > 0.01). The method with CGMS is reliable and comfortable for both tested persons and investigators. Hence, it appears to become a sophisticated approach to determine the GI.

Cyclic strain behaviour of metastable austenitic 301LN steel with different grain sizes – coarse (14 μm) and ultrafine (1.4 μm) grained – produced by the special thermo-mechanical treatment based on the martensite-to-austenite reversion was investigated. Low-cycle fatigue (LCF) tests were conducted on flat specimens at room temperature in fully push-pull mode under strain control with constant strain rate of 2×10 –3 s –1 and constant total strain amplitude ranging from 0.4% to 0.9%. LCF behaviour was characterised by cyclic hardening/softening curves and fatigue life curves. After completion of fatigue tests surface fatigue damage was studied using scanning electron microscopy (SEM). Ferritoscope was adopted to reveal the destabilization of austenitic structure and evaluate the extent of deformation induced martensitic transformation.

Viral hepatitis B still represents a major epidemiological issue worldwide. After recombinant vaccine administration, a titer of anti-HBs antibodies ≥ 10 IU/L has long been considered to be seroprotective. Persons without this antibody level after complete vaccination are referred to as non-responders. A progressive decline in anti-HBs levels over years is also commonly seen in responders. Recently, there has been increasing evidence that the titer of anti-HBs ≥ 10 IU/L does not provide 100 % protection against infection and clinically manifest illness. Additionally, an important role of cellular immune memory has been demonstrated - without any correlation with anti-HBs titer. Based on current knowledge, there is no need for regular anti-HBs titer testing or booster vaccination in immunocompetent individuals with anti-HBs ≤ 10 IU/L. At present, regular serological testing and, if need be, revaccination to maintain anti-HBs ≥ 10 IU/L are recommended in immunocompromised persons and after liver transplantation.

Measurement of the short fatigue crack propagation can come across a lot of difficulties from the experimental point of view and interpretation of the results is also sometimes controversial. For simplicity, usual description of the short cracks is based on linear elastic fracture mechanics (using the concept of stress intensity factor). In this case, significant differences between short cracks and long cracks are usually presented. Most of the discrepancies are simply given by non-validity of the linear elastic fracture mechanics approach. In our case of physically short fatigue cracks the level of applied stress is close to cyclic yield stress of the material and, due to large amount of plasticity, conditions of linear elastic fracture mechanics are not satisfied. As a consequence, non-linear elastic plastic fracture mechanics is used for description of the short crack behavior in this article. Concept based on plastic part of J-integral is proposed for the description of the short crack behavior and data obtained for different strain amplitudes are compared. This concept is validated on experimental data obtained on steel 316L. Měření šíření krátkých únavových trhlin může narazit na mnoho obtíží z experimentálního hlediska a interpretace výsledků je také někdy kontroverzní. Pro jednoduchost je obvyklý popis krátké trhliny založen na lineární elastické lomové mechanice (pomocí faktoru intenzity napětí). V tomto případě jsou obvykle prezentovány významné rozdíly mezi krátkými a dlouhými trhlinami. Většina nesrovnalostí je však zpravidla dána neplatnosti předpokladů lineární elastické lomové mechaniky v případě krátkých trhlin. V našem případě fyzicky krátkých únavových trhlin se použité zatížení blíží cyklciké mezi kluzu materiálu a kvůli výrazné plastické deformaci nejsou splněny podmínky lineární elastické lomové mechaniky. Proto je v tomto příspěvku k popisu chování krátkých trhlin použito elasto-plastické lomové mechaniky. Je navržen koncept pro popis chování krátkých trhlin založený na použití plastické části J-integrálu a jsou porovnána data obdržená pro různé hodnoty amplitudy přetvoření. Tento koncept je ověřen na experimentálních datech získaných na oceli 316L.

Rituximab, a monoclonal antibody against the surface antigen of B-lymphocytes CD20 is beeing used in the treatment of numerous hematological, hematooncological and autoimmune disorders. After administration of ritu-ximab, quick and almost complete depletion of B-lymphocytes with the exception of pre-B-lymphocytes and plasma cells occur. Neutropenia and low serum antibody levels in classes IgA, IgM and IgG may also develop. These changes usually persist for 6-12 months, rarely for several years. In the consequence, patients with the rituximab treatment are more prone to infections - usually of bacterial and viral origin. Concomitantly, rituximab treatment influences negatively postvaccination antibody production and therefore adequate preventive measures are necessary before the beginning of the treatment. The authors offer complex overview of actual literature, emphasize adequate education of patients as well as of healthcare providing staff and discuss the vaccination recommendation against preventable communicable diseases like influenza, pneumococcal diseases, tetanus, diphtheria and pertussis.autoimmune disease - immunosupression - infectious complications - prevention - rituximab - vaccination.

Cyclic multiple step test in strain control have been performed on cylindrical specimens of cast polycrystalline Inconel 738LC and 792-5A superalloys at 800 °C in laboratory atmosphere. Hysteresis loops were analyzed according to the statistical theory of hysteresis loop. The effective and internal stress components were evaluated. The effective stress of γ´ precipitate has significant influence on the stress-strain response both materials. The stress amplitude in IN 792-5A is higher than in IN 738LC at approximately same total strain amplitude due to significantly higher effective stress of γ´ phase. Cyclic hardening/softening curves and cyclic stress-strain curves using short-cut procedure were obtained. Cyclic hardening/softening behavior depends both on temperature and strain amplitude. Low amplitude straining is characterized by the saturation of the stress amplitude. In high amplitude straining slight softening was found. The cyclic stress-strain curves for both materials can be fitted by power law. Cyclic stress-strain response in terms of internal and effective stress components is discussed in relation to microstructural parameters of the materials. The observation of surface relief revealed the presence of persistent slip markings.

The response of materials to cyclic loading using different loading conditions is analyzed. Hysteresis loops of austenitic steel cycled in symmetric and asymmetric strain- and stress controlled loading are analyzed to evaluate the contribution of effective stress and probability distribution of internal critical stresses. The austenitic-ferritic duplex steel is cycled with various positive mean stresses and cyclic stress-strain response, cyclic creep rates, resulting dislocation structures and fatigue life are evaluated. The effect of the mean stress on cyclic plasticity and fatigue life is discussed. © 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of ICM11

Cylindrical specimens of cast polycrystalline nickel base superalloy Inconel 738LC were cyclically strained under total strain control at 23 and 800 °C to fracture. Cyclic hardening/softening curves, cyclic stress-strain curves, and fatigue life curves were obtained at both temperatures. Surface relief was studied in specimens fatigued to failure using scanning electron microscopy. Cyclic hardening/softening behaviour depends both on temperature and strain amplitude. Low amplitude straining was characterized by saturation of the stress amplitude. In high amplitude straining a pronounced hardening was found which was followed by saturation at room temperature and by cyclic softening at 800 °C. The cyclic stress-strain curves can be fitted by power law. They are shifted to lower stresses with increasing temperature. Fatigue life curves can be approximated by the Manson- Coffin and Basquin laws. The Manson-Coffin and Basquin curves are shifted to lower lives with increasing temperature. Slip markings were detected on specimen surface at all test temperatures. When temperature grows the density of slip markings is reduced.

Background: The glycemic index (GI) is a measure of the ability of a food to raise glucose levels after it is eaten. Continuous glucose monitoring (CGM) has been shown to give identical values of GI when compared to traditional methods. However, there has been no standardized protocol for measuring GI that takes into account interindividual variability and chronophysiological glycemic response to food. Our aim was (1) to create and describe software based on a Microsoft Excel 2000 spreadsheet to facilitate rapid, automated, accurate, and standardized processing of data obtained using recent CGM methodology to measure GI and its variability and (2) to assess the benefits of this new approach. Method: Twenty healthy subjects consumed 50 grams of glucose or four alternative foodstuffs (chocolate, apple baby food, rice squares, or yogurt) at breakfast and dinner during 1 week, resulting in 300 CGMS glucose profiles; 92% of meal tests were satisfactory for evaluation. Application and functions of the software DegifXL are described. Results: Using the new spreadsheet software DegifXL, time required for data processing for the 15 data sets for each subject was reduced from 2000 to 160 minutes relative to previously used manual methods. We characterized the GI for four foodstuffs with three replicate measurements in each of 20 subjects and evaluated between person, between time period, and between replicate GI variabilities. Conclusion: DegifXL, combined with CGM, was an efficient and effective tool for routine measurement of group- and subject-related GI.

This diploma thesis is interested in usage of Electron Beam lithography process as an instrument of transport of contacts and catalytic layers to micro-channels of the micro monolithic planar fuel cell. Experimental part includes optimization of the PMMA resist deposition method on the 3D topography - spray coating - is performed with alternative spray coating system. The optimal spin speed resist, molecular weight and concentration is chosen during the optimization. Parameters of the exposition, developing and lift-off are also modified and three EBL processes are performed. The first ensures deposition of Au contacts to the channels; the second is for application of Pt layer to the cathode channel and the last aimed to cover the anode channel with CeO/CNx layer. All layers are deposited by magnetron sputtering.

UNLABELLED The glycaemic index (GI) is a measure of the food power to raise blood glucose (B-glucose) concentration after a meal. For healthy eating, foods with low GI are recommended. However, for many foods in the European Union the GI has not been defined yet. The aims of this prospective open-label study were: (1) to determine the GI of white bread and juicy cereal bars FIT (Usovsko, Czech Republic) by means of the glucometer Optium (Abbott/Medisense); (2) to compare the GI of tested foods determined in the morning and in the evening hours; (3) to compare the GI of tested foods in men and women and (4) to assess the variability of the GI. METHODS To determine the GI, measured portions of food containing 50 g of carbohydrates were eaten by 11 healthy volunteers. B-glucose curves were constructed from B-glucose values at time 0, 15, 30, 45, 60, 60, 120 min after the meal. The GI was calculated by dividing the incremental area under the curve (IAUC) for the tested food by that for the standard food (IAUCS). In each volunteer each food was tested 5 times so that 5 GI's was obtained and the average was calculated. The GI for each tested food was calculated as the mean from the respective average GI's of the 11 volunteers. MS Excel and the statistical program SPSS v. 10.1 were used to analyze the data. RESULTS (1) The mean values of the GI for white bread was 70.3 % and for juicy cereal bars was 101.0 %, as determined in a total of 139 tests in the whole group of 11 volunteers. There was a difference when comparing white bread vs. glucose (p = 0.012) and white bread vs. cereal bars (p = 0.026) but no difference between glucose and cereal bars. (2) There was no significant difference between the GI determined in the morning and in the evening hours either for the total of 139 tests or for the individual tested foods. (3) No significant difference could be seen between the GI in men and women when comparing glucose, cereal bars and white bread. (4) There was a wide variability of GI in all tested foods: the standard deviation of GI for white bread was 30.7 %, for juicy cereal bars 38.0 %. CONCLUSIONS The GI's for white bread and juicy cereal bars were determined. There was no difference either between the GI values determined in the morning vs. the evening hours or between the values in men vs. women. The results show wide variability. An accurate standard method for the determination of GI needs to be defined, carefully used and re-evaluated to enable a comparison of the results with various methods of other working groups.

The aim of this paper is to prove the possible reproducibility of measurement with a new developed device for artery elasticity monitoring and determining the standard of major pulse wave parameters. As a measurement sensor, a conic probe with thin convex membrane was used. This technique allows setting an arbitrary pressure to a measured surface artery. We measured pulse waves on the radial arteries of 108 individuals. We expected similar features in arterial wall elasticity. We concentrated primarily on the amount of subcutaneous fat. For the measured waves we evaluated five following pulse wave parameters: relative crest time, elasticity index, dicrotic wave attenuation, dicrotic wave time and interwave distance. There were no significant differences in measured pulse wave parameters among the tested groups of subjects.

The main topic of the diploma thesis is the financial analysis of the chosen company. The first part consists of a theoretical basis of the issue involving these areas - region, business environment and economic analysis. The second part is focused on the practical implications with formation of the economic analysis of the chosen company, characteristics of the region and the industry in which the company operates as well as suggestions of improvements.

Six grades of TiAl alloys doped with 7 at.% Nb and variable content of C and/or Mo were studied. The as-received microstructure and phase composition of the alloys was characterized using neutron diffraction experiments and electron microscopy. They are substantially different in individual alloys. In Mo containing alloys, ordered beta0 phase is present while carbon suppresses the occurrence of this phase. Alternating lamellae of gamma and alpha2 phases are characteristic for all specimens. The specimens have been subjected to monotonic testing (tensile and compression) and to low cycle fatigue testing at ambient and at elevated temperatures. The differences in microstructure result in scatter of mechanical behaviour of the alloys, e.g. the yield stress at 750C varies from 445 to 626 MPa. The mechanical properties of the materials are discussed in relation to the initial microstructure and phase composition. Bylo studováno šest typů TiAl slitin legovaných 7 at.% Nb a různým množstvím C a/nebo Mo. Charakterizace mikrostruktury „as-received“ stavu a složení fází byla provedena pomocí neutronové difrakce a elektronové mikroskopie. Vzorky byly podrobeny monotónním testům (tah a tlak) a také nízkocylkové únavě jak za pokojových tak za zvýšených teplot. Rozdíly v mikrostruktuře vedou k různým mechanickým vlastnostem jednotlivých typů slitin.