Investigating the thermal and irradiation stability of chemical vapor deposited erbium oxide tritium barrier coatings for Li breeder blanket applications

Two-micron thick erbium oxide tritium barrier coatings have been prepared by aerosol injection chemical vapor deposition and subsequently irradiated with 33 MeV Au 6+ ions at fluences up to 2.1 × 1016 Au/m2 at 550°C. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy were used to investigate the coating surface morphologies, phase structures and cross-sectional microstructures as a function of irradiation and thermal treatment. XRD data was also used to extract information about the evolution of lattice strain in the coating. Some of the cubic erbia transformed to the monoclinic phase in the sample that was ion irradiated at temperature, and this was accompanied by a change from columnar to a more equiaxed grain structure. All coatings were found to experience out-of-plane tensile strain, thought to originate from thermal stresses created during coating manufacture. Thermal treatment reduced microstrains present in the as-deposited sample, whilst the cubic-to-monoclinic phase transformation reduced strain in the cubic phase but increased strain in the monoclinic phase

Pneumatikus hajtású tanulmányautó telemetriai mérőrendszerének kialakítása

A tanulmányban egy speciális telemetriai mérőrendszer kialakítását mutatjuk be, mely a Debreceni Egyetem Műszaki Karán fejlesztett pneumatikus hajtású jármű pneumatikus motorjának és dinamikai paramétereinek működés közbeni mérésére, adatgyűjtésére alkalmas. A jármű vizsgálatához, felhasználtunk egy programozható logikai vezérlőt (PLC-t), mely a különböző szenzorok jeleit dolgozza fel, valamint a National Instruments LabVIEW fejlesztőkörnyezet segítségével elkészítettünk egy alkalmazást, ahol a különböző paraméterek valósidejű megfigyelésére, valamint azok mentésére is van lehetőség, a későbbi adatfeldolgozáshoz. A megbízhatóság érdekében a berendezés érzékelő, végrehajtó és vezérlő egységei, ipari eszközök segítségével kerültek kialakításra

Characterization of Irradiation Damage Using X-Ray Diffraction Line-Profile Analysis

During operation, structural components made of zirconium alloys are subject toneutron irradiation, which leads to the displacement of zirconium atoms fromtheir lattice sites, the production of self-interstitials and vacancies, and eventually dislocation loops. This process can lead to deleterious effects such as irradiation growth, creep, and embrittlement as well as accelerated aqueous corrosion. Quantitative analysis of dislocation line densities is seen as an importantpathway for distinguishing between the irradiation response of different alloys.The analysis of irradiation damage using X-ray diffraction (XRD) line-profile analysis has proven to be a powerful complementary technique to transmissionelectron microscopy, which samples a comparatively large volume and is lessaffected by the subjectivity of image analysis. In this paper we present andanalyze three different types of XRD experiments, describing their purpose andthe new insight achieved using each technique. First, we present work carriedout on neutron-irradiated samples, comparing dislocation line densities measured by XRD with macroscopic growth measurements. A second experimentusing a synchrotron-based X-ray microbeam enabled the mapping of dislocationline densities as a function of depth from the surface of proton-irradiated zirconium alloys. These data are compared with calculated damage profiles, providingnew insight into the early saturation of damage. Finally, the last example presented here focuses on synchrotron-based 3D XRD measurements, for whichdislocation-loop line densities were analyzed in hundreds of individual grains,providing excellent statistics about the grain-to-grain variability of line densities

Elektromos járművek tervezése és építése. Múlt és jövő

Elektromos járművek már a 19. század közepén megjelentek, amikor többek között az elektromos meghajtás részesült előnyben, mivel olyan kényelmi és vezetési szintet biztosítottak, amit az akkori benzines járművek nem értek el. Napjainkban ezek a járművek világszerte népszerűek. Egyetemünk 2008 óta vesz részt különböző hazai és nemzetközi alternatív meghajtású diákversenyeken: Pneumobil, Elektromobil, Széchenyi Futam, AltRace, MVM Energia. A cikk bemutatja a verseny eredményeket. Legújabb kihívásunk a Shell Eco-marathon

CHARACTERISATION OF HYDRIDE PRECIPITATION AND REORIENTATION IN ZIRCALOY-4 AT DIFFERENT METALLURGICAL STATES

Hydride precipitation and reorientation has the potential to embrittle zirconium alloys. This study aims to better understand the influence of the Zr microstructure on hydride precipitation and reorientation. Specifically, the crystallography, phase stability and morphology of hydride precipitation was correlated to microstructural variations due to changes in the metallurgical state of the zirconium alloy. The work highlights, that microstructural features induced during recrystallisation have a significant influence on the distribution and orientation of hydrides when no external stress is applied. The stability of ϒ-hydride was shown to be dictated by metallurgical state whereby its formation was promoted in the recrystallised sample owing to its reduced strength. The influence of grain orientation on ϒ stability was also explored. It was highlighted that upon cooling, grains oriented in the <101 ̅0> direction are under compression such that ϒ-hydride formation is supressed. This study suggests that the extent of reorientation is driven by differences in hydrogen content of the alloy as well as the applied stress during reorientation, whilst the influence of the metallurgical state still remains unclear. Quantification of the dislocation density in both the matrix and hydride during precipitation highlighted that extensive matrix recovery takes place during hydriding. It was also shown that the dislocation density in the hydride is lower after thermomechanical loading whereby the presence of dislocation nests left behind after initial hydride precipitation and dissolution could provide more space for the hydride to precipitate into

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Slip systems and dislocation densities in individual grains of polycrystalline aggregates of plastically deformed CoTi and CoZr alloys

A novel X-ray diffraction-based technique for grain-by-grain assessment of dislocation density within polycrystals is applied. The technique discriminates dislocation densities of different slip modes, slip systems and dislocation character. Data which was formerly confined to the transmission electron microscope (TEM) is now available from X-ray diffraction (XRD). In addition, there is a profound statistical advantage of the XRD approach over the traditional TEM-based approach. Over 130 grains were analyzed for one sample of CoTi, which would be a Herculean task on the TEM, requiring dozens of samples as well as numerous hours on the microscope and analysis of the images generated for each sample. The present experiments were performed in about 30 h per sample and the analysis is semi-automated, involving a Monte-Carlo-type algorithm to determine the dislocation structure best representing the single crystal diffraction peak profiles in a polycrystalline aggregate. Conclusive confirmation of a previously suggested explanation for the anomalous ductility of two CsCl structured intermetallic compounds, CoTi and CoZr, is provided: namely, that hard dislocation modes, with b = 〈1 1 0〉 and 〈1 1 1〉, rarely observed in single crystal experiments, are active in nearly every grain. The results call into question the value of employing single crystal deformation experiments alone to understand the deformation behavior of polycrystalline materials. Further, the results re-emphasize that the uniform stress assumption implicit in Schmid factor analysis is a poor one for materials which are highly anisotropic at the single crystal level