Assessment of the Al–Fe–Ti system

The Al–Fe–Ti system has been assessed and the limiting binary systems are shortly reviewed. Based on a thorough review of the literature, isotherms at 800, 900, and 1000 °C have been re-evaluated and a provisional isotherm at 1200 °C is presented for the first time. The effect of alloying the binary phases with the third component is reviewed with regard to the ternary homogeneity ranges, crystallography, order/disorder transformations, and site occupancies. Of the variously reported ternary compounds only the existence of “Al2FeTi” (τ2) and “Al8FeTi3” (τ3) is confirmed. The occurrence of the phases τ2*, τ′2, and of a new stacking variant of TiAl is still under discussion, while the existence of the phases Fe2AlTi (τ1) and Fe25Al69Ti6 (X) is ruled out. The presented reaction scheme corroborates the isothermal sections and also a representation of the liquidus surface is given. Magnetic, electrical, thermochemical, atomistic and diffusion data for Al–Fe–Ti alloys are summarised and an overview about studies on modelling of phase equilibria and phase transformations is given

Trends of COVID 19 Vaccines: International Collaboration and Visualized Analysis

Objective: We aimed to evaluate the research and publication trends on the coronavirus disease (COVID-19) vaccine, and so guide future studies.Materials and Methods: A bibliometric analysis was performed using a VOSviewer visualization methodology. Information about publications Web of Science database outputs, countries, institutions, journals, keywords, and citation counts was retrieved.Results: A total of 929 eligible publications from January 1, 2020, to February 28, 2021, were derived from the WOS database according to the search criteria. Publications were written in nine languages, mainly in English (96.7%). From these results, a total of 300 articles were reached by filtering. The average number of citations was found to be 7.73. The H-index of the articles, which were cited 2320 times in total, was 22. Most of the publications were articles (32.29%) and editorials (28.09%). There were 73 different research areas, mostly in general internal medicine (26.6%) and immunology (19.05%). The United States of America produced the majority of articles (31.32%). Conclusion: This bibliometric analysis presents that publications on the COVID-19 vaccine are rapidly changing at a time when exactly the effective vaccines of COVID-19 have not been discovered yet

Bibliometric Analysis of Human Metapneumovirus Studies

Objective: This study aimed to estimate research productivity and general characteristics of research in different regions of the world in the field of human metapneumovirus (hMPV). Materials and Methods: We used the Web of Science (WoS) electronic database to retrieve articles on human metapneumovirus, published up to March 31, 2023. Parameters such as research productivity, the total number of publications, average citation counts of all ar-ticles, research productivity by top publishing countries and affiliated organizations, links between countries/organizations, and top keywords were assessed. Results: We found 826 articles in the WoS database. The first article on hMPV was pub-lished in 2002, and 2008 was the year that the most articles on hMPV were published, with 70 articles. The articles were cited 26,797 times (14,498 times without self-citations) and 32.25 times on average per article. Hirsch (H)-index was 80. The year 2008 also had the highest number of citations, with more than 1800. The United States was the most pro-ductive country, producing 295 documents (35.714%), one-third of all publications in this field worldwide. Canada (6.5%) and Japan (6.5%) followed the United States regarding total hMPV publications worldwide. The leading funding agencies for hMPV research were from the United States, Europe, China, and Japan. Conclusion: Our findings imply that developed countries should assist developing countries in enhancing their research infrastructures

Kinetics, thermodynamics and mechanism of metastable Al-AlmFe phase and fir-tree zone formation in DC-cast Al-Fe-Si alloy ingots

In DC-cast 1xxx-series aluminum alloy ingots, the presence of Fe and Si, and cooling rates increasing from < 1°C/s in the ingot center to ~20°C/s near the surface cause the formation of metastable intermetallic Al6 Fe and AlmFe compounds in addition to the stable Al 3Fe. The highly contrasting etching/anodizing response of the Al 6Fe and AlmFe particles forming in the adjoining central and peripheral regions, respectively, creates the fir-tree zone (FTZ) defect in DC-cast ingots. This, in turn, causes streaking in Al sheets.The need was great for a good fundamental understanding of the mechanism of metastable Al-A1mFe eutectic phase formation. Therefore, the mechanism was studied via the kinetic (experimental: Bridgman growth and DSC analyses), thermodynamic (macroscopic: phase diagram computation), and crystallographic (atomistic) approaches.The controlled growth of Al-Al3Fe, and metastable Al-Al xFe, Al-Al6Fe, and Al-AlmFe eutectic phases was obtained in AA1050 and its binary analogue Al-0.33wt% Fe alloys via Bridgman growth at various growth velocities (V = 0.15 -60 mm/s). For each phase, by acquiring a series of growth-velocity-dependent invariant (for binary alloys) and univariant ( for AA1050) melting temperatures (T) via DSC, the binary and ternary melting and growth kinetics were determined as T vs ln(V) plots extrapolated to V = 0.001 mm/s.Using the binary melting kinetics and tentative growth kinetics plots, the Gibbs free energy parameters of binary phases in the AA12S database were optimized, and the previously non-existent binary and ternary stable and metastable equilibrium phase diagrams (computed at V = 0.001 mm/s) and stable and metastable kinetic and dynamic phase diagrams (computed at the DC-casting velocity; V = 1 mm/s) were obtained via ThermoCalc(TM)

Elimination of shrinkage microporosity in magnesium castings by strontium additions

In this study a technique--that almost completely eliminates shrinkage microporosity--has been developed which uses small additions of strontium together with risers and chills to produce porosity-free AZ91C (Mg/Al/Zn) magnesium casting alloy castings. With the optimum level of Sr addition (0.01% to 0.02% Sr), shrinkage microporosity was removed from the casting and concentrated in the riser. The castings were already grain-refined by carbon inoculation. The effect of strontium is explained by a further reduction in the grain size of the castings from 250$mu$m to 120$mu$m. This effect produces a much denser casting due to increased mass feeding. In addition, a slow grain growth rate, caused by Sr addition, may keep the liquid intergranular-channel radius large during the final stages of solidification, and results in improved intergranular feeding. Another effect of strontium addition may possibly be attributed to a decrease in the surface tension and viscosity of the liquid AZ91C alloy, which in turn increases capillary feeding of the liquid metal. (Abstract shortened by UMI.