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A special open-hole sheet specimen of GLARE fiber-metal laminate was used to simulate mixed loading similar to the loading of a riveted hole in a real fuselage skin structure. The effect of cyclic tension and secondary bending loading was studied. The notch region was observed through a microscope in order to detect the first fatigue crack initiation during fatigue loading. The number of cycles prior to crack initiation was measured, and the crack growth rate in the surface layer of the laminate was evaluated. The specimens were subjected to fatigue damage investigation in the inner layers of the laminate after termination of the test. A significant effect of secondary bending on fatigue crack initiation and early crack growth was found. The experimental results are discussed in terms of local stress-strain conditions in the notch region evaluated by means of finite element calculation.

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 °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 °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 1000–1200 °C in the near future.

AISI 4130 steel is widely used in the aircraft industry, mainly for frame structures. It is a medium carbon low-alloyed (25CrMo4) steel predetermined for precipitation of carbides in the microstructure during heat treatment. Six different heat treatments were applied to study the effect of the resulting microstructure (ferritic-pearlitic in a normalised state or martensitic with carbides in a hardened state) on the fatigue life of AISI 4130. Tension-tension cycling under force control was used to determine the S-N curve of flat specimens with a central circular notch. The best fatigue properties were achieved for the material state HT125, i.e., hardened & tempered to 125 ksi (863 MPa), exhibiting the maximum stress at a fatigue limit of 225 MPa, which is approximately 5-15 % better compared to the rest of the applied heat treatments. Microstructural investigations using scanning electron microscopy explained the acquired fatigue life results of AISI 4130 concerning different heat-treated conditions. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse the effect of Instagram usage reduction on the psychological well-being of young adults. Participants (n = 72) were randomly assigned into three groups, the experimental group (n = 25) used Instagram for a maximum of 10 minutes a day and turned off notifications, the active control group (n = 24) turned off notifications, and the passive control group (n= 23) used Instagram without any restriction. Baseline monitoring took place in the first week followed by three weeks of experimental intervention. The results showed a significant decrease in depressive symptoms (F (1.67) = 20.86; p < .001), negative emotions (F (1.67) = 7.85; p = .007), loneliness (F (1.67) = 4.69; p = .034) and increase in self-esteem (F (1.67) = 8.347; p = .005) and positive emotions (F (1. 67) = 7.40; p = .008) across the sample, i.e., in both experimental and control groups. The improvement in psychological well-being without significant differences between the groups can be attributed to monitoring the use, so the fact that we have an overview of our own use of Instagram can bring benefits. The measured values are listed in the English appendix (link). [ABSTRACT FROM AUTHOR]

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.

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Copyright of Anaesthesiology & Intensive Medicine / Anesteziologie a Intenzivní Medicína is the property of Czech Medical Association of JE Purkyne and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Prophylactic treatment is standard care for most children with severe haemophilia A and maintaining this treatment in adulthood is recommended. However, the situation differs in adult patients with severe haemophilia A previously treated on demand. Between 2008-2015, we performed the following comparison of selected patients with severe haemophilia A. Over one year, we compared the frequency of bleeding episodes in a group of 8 patients aged 20-27, median (average) 22 (22.5) on continued prophylactic treatment from childhood with a group of 8 patients aged 26-65, median (range) 36 (37.5) treated on demand. Meanwhile, this same group was compared after performance of prophylactic treatment. In this group of patients, an individual period of 12 months was chosen and during which a specific patient did not undergo any invasive treatment, or had any serious bleeding episode after injury. Consequently, these patients were observed for another year (12 months), which ideally followed after their switch to prophylactic treatment. A group of patients with severe haemophilia A on prophylactic treatment was included as soon as they had been referred from the Department of Paediatric Haematology University Hospital Brno if they had not undergone in that particular period any invasive treatment or suffered any serious bleeding episode after injury. Patients were selected at a time when not subjected to any invasive procedure or suffering severe bleeding requiring hospitalization. Our results showed that by switching adult patients with frequent bleeding episodes from on demand treatment to prophylactic treatment, bleeding episodes were reduced by 82% (joint bleeds by 79%), without significantly increasing treatment cost. The median (range) of bleeding episodes in the young patient group with ongoing prophylaxis from childhood was 0 (average 0.375) times per year. The median (range) of bleeding joint episodes in older adult patients with on demand treatment was 27.5 (26). The median (range) 3.5 (4.8) number of bleeds decreased significantly with prophylaxis. Secondary prophylaxis in adult patients with severe haemophilia A significantly reduces the frequency of joint bleeds compared with on demand treatment. Prophylactic treatment of adults is certainly advantageous in certain complicated cases of haemophilia. In the future, costly surgery such as orthopaedic interventions could be postponed in these patients. [ABSTRACT FROM AUTHOR]

Autorka článku nás seznamuje s historií institutu povinného výtisku od jeho ustavení v první polovině devatenáctého století do současné doby. Od původního zaměření na cenzuru k dohledu nad vydavatelskou činností k jeho zcela zásadnímu významu pro tvorbu národní bibliografie a uchovávání národní literatury. Nepomíjí však současné problémy, které vznikají z roztříštěnosti knižního trhu a množství malých nakladatelství, které nerespektují požadavky zákona o povinném výtisku. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 °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 °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 1000–1200 °C in the near future. [ABSTRACT FROM AUTHOR]