Abstract The article will be focused on examining and comparing the influence of structure, sensitization and corrosion on the fatigue properties of austenitic stainless steel. The methodology of the ...experiment includes fatigue tests of samples attacked by intercrystalline corrosion. Therefore, the test samples were subjected to heat treatment for sensitization. Then these samples were subjected to long-term exposure in an aggressive corrosion solution. Experiments deal with microstructural material analysis, fractographic analysis, mechanical and fatigue tests.
Abstract The article will be focused on the analysis of the influence of heat treatment on the nitriding layer, which will be applied on austenitic steel. AISI 304 austenitic steel delivered without ...heat treatment will be used as experimental material. The nitriding layer will be applied to the austenitic steel samples by plasma nitriding. Then, after plasma nitriding, samples will be subjected to heat treatment. Solution annealing and sensitization will be chosen as heat treatment. Experiments deal with microstructural material analysis, fractographic analysis, mechanical and fatigue tests.
Sterile neutrinos are a minimal extension of the standard model of particle physics. A promising model-independent way to search for sterile neutrinos is via high-precision β-spectroscopy. The ...Karlsruhe tritium neutrino (KATRIN) experiment, equipped with a novel multi-pixel silicon drift detector focal plane array and read-out system, named the TRISTAN detector, has the potential to supersede the sensitivity of previous laboratory-based searches. In this work we present the characterization of the first silicon drift detector prototypes with electrons and we investigate the impact of uncertainties of the detector's response to electrons on the final sterile neutrino sensitivity.
We report on the magnetic properties of antiferromagnetic NiO(001) thin films in epitaxially grown NiO/MgO(d
)/Cr/MgO(001) system for different thicknesses of MgO, d
. Results of X-ray Magnetic ...Linear Dichroism show that together with an increase of d
, rotation of NiO spins from in-plane towards out-of-plane direction occurs. Furthermore, we investigated how the proximity of Fe modifies the magnetic state of NiO in Fe/NiO/MgO(d
)/Cr/MgO(001). We proved the existence of a multidomain state in NiO as a result of competition between the ferromagnet/antiferromagnet exchange coupling and strain exerted on the NiO by the MgO buffer layer.
The magnetic properties of Co(10 Å)/NiO(40 Å)/Fe trilayer epitaxially grown on W(110) substrate were investigated with use of x-ray magnetic linear dichroism (XMLD) and x-ray magnetic circular ...dichroism (XMCD). We showed that magnetic anisotropy of Fe film that can be controlled by a thickness-driven spin reorientation transition is transferred via interfacial exchange coupling not only to NiO layer but further to ferromagnetic Co overlayer as well. Similarly, a temperature driven spin reorientation of Fe sublayer induces a reorientation of NiO spin orientation and simultaneous switching of the Co magnetization direction. Finally, by element specific XMCD and XMLD magnetic hysteresis loop measurements we proved that external magnetic field driven reorientation of Fe and Co magnetizations as well as NiO Néel vector are strictly correlated and magnetic anisotropy fields of Fe and Co sublayers are identical despite the different crystal structures.
Sterile neutrinos are a minimal extension of the Standard Model of Particle Physics. If their mass is in the kilo-electron-volt regime, they are viable dark matter candidates. One way to search for ...sterile neutrinos in a laboratory-based experiment is via tritium beta decay, where the new neutrino mass eigenstate would manifest itself as a kink-like distortion of the spectrum. The objective of the TRISTAN project is to extend the KATRIN setup with a novel multi-pixel silicon drift detector system to search for a keV-scale sterile neutrino signal. First seven-pixel prototype detectors were produced and characterized with radioactive X-ray and electron sources. The next prototype generation with 166 pixels is currently in production and will be available beginning of 2019. In this work, we describe the requirements of the novel TRISTAN detector system and present the technical realization of the first prototypes.
Vaccine effectiveness studies have not differentiated the effect of the delta (B.1.617.2) variant and potential waning immunity in observed reductions in effectiveness against SARS-CoV-2 infections. ...We aimed to evaluate overall and variant-specific effectiveness of BNT162b2 (tozinameran, Pfizer–BioNTech) against SARS-CoV-2 infections and COVID-19-related hospital admissions by time since vaccination among members of a large US health-care system.
In this retrospective cohort study, we analysed electronic health records of individuals (≥12 years) who were members of the health-care organisation Kaiser Permanente Southern California (CA, USA), to assess BNT162b2 vaccine effectiveness against SARS-CoV-2 infections and COVID-19-related hospital admissions for up to 6 months. Participants were required to have 1 year or more previous membership of the organisation. Outcomes comprised SARS-CoV-2 PCR-positive tests and COVID-19-related hospital admissions. Effectiveness calculations were based on hazard ratios from adjusted Cox models. This study was registered with ClinicalTrials.gov, NCT04848584.
Between Dec 14, 2020, and Aug 8, 2021, of 4 920 549 individuals assessed for eligibility, we included 3 436 957 (median age 45 years IQR 29–61; 1 799 395 52·4% female and 1 637 394 47·6% male). For fully vaccinated individuals, effectiveness against SARS-CoV-2 infections was 73% (95% CI 72–74) and against COVID-19-related hospital admissions was 90% (89–92). Effectiveness against infections declined from 88% (95% CI 86–89) during the first month after full vaccination to 47% (43–51) after 5 months. Among sequenced infections, vaccine effectiveness against infections of the delta variant was high during the first month after full vaccination (93% 95% CI 85–97) but declined to 53% 39–65 after 4 months. Effectiveness against other (non-delta) variants the first month after full vaccination was also high at 97% (95% CI 95–99), but waned to 67% (45–80) at 4–5 months. Vaccine effectiveness against hospital admissions for infections with the delta variant for all ages was high overall (93% 95% CI 84–96) up to 6 months.
Our results provide support for high effectiveness of BNT162b2 against hospital admissions up until around 6 months after being fully vaccinated, even in the face of widespread dissemination of the delta variant. Reduction in vaccine effectiveness against SARS-CoV-2 infections over time is probably primarily due to waning immunity with time rather than the delta variant escaping vaccine protection.
Pfizer.
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