Lubrication of Mo, W, and their Alloys with H2S gas admixtures to room temperature air
Abstract The in situ lubrication of molybdenum and tungsten using admixtures of hydrogen sulfide to room temperature and pressure air was achieved. Raman spectroscopy confirmed the presence of molybdenum disulfide and tungsten disulfide solid lubricants on elemental molybdenum and tungsten specimens, respectively. Pin-on-disk experiments were conducted with elemental molybdenum, elemental tungsten, and alloys of molybdenum and tungsten in atmospheres containing hydrogen sulfide. Friction coefficients were continuously recorded and comparisons between the sliding friction coefficient in air and in the hydrogen sulfide atmospheres were evaluated. In general, hydrogen sulfide admixtures reduced the friction coefficient for all materials containing molybdenum or tungsten. Friction coefficients for self-mated elemental molybdenum and self-mated elemental tungsten were reduced to μ =0.15 with hydrogen sulfide admixtures to air of 5% and 15%, respectively. In some cases friction coefficients as low as μ =0.08 were recorded.
Correlation between thermochemical and antiscuff characteristics of organosulfur compounds
Thermochemical and antiscuff characteristics of organosulfur compounds in solutions of Vaseline oil, oligodiethylsiloxane, and hexadecane have been studied. A high correlation of their thermochemical and antiscuff characteristics in the solution of Vaseline oil is demonstrated. The radical-based antiscuffing mechanism of organosulfur compounds is discussed. It is proved that antiscuffing tests of organosulfur compounds in solution of hexadecane do not simulate tests in Vaseline oil.
Snapshots of the Balkans through ethnographic investigation of the linguistic landscape
This paper investigates the linguistic landscape of Dubrovnik and Kotor on the Southeastern Adriatic coast, and Mytilene in the north Aegean attempting a theorization of its findings at the intersection of (socio)linguistics, ethnography, and semiotics, which has gained ground as the platform of choice in linguistic landscape (LL) research. I argue that the influx of both tourists and refugees, despite the obvious differences between the two groups, has had radical consequences for the LL which have so far attracted virtually no attention in the relevant literature. And yet, tourism and the arrival of new populations have considerable and lasting effects on the LL which can only be adequately investigated by systematic ethnographic studies of the semiotic means employed in inscribing it. Nevertheless, ethnography, as a methodological sociolinguistic tool, cannot substitute or supersede cognitive aspects of language. If doing LL research means doing semiotic landscape research, then we also have to consider semiosis and higher-order indexicality qua categorization. I understand ethnographic LL research as contributing to a better comprehension of the dynamic indexical relation between language and physical space (turned into place through human agency). Just as a certain accent and particular morphosyntactic choices may index the place of origin of a speaker, a specific LL may index populations and their socioeconomic relations at a certain historical moment. Focusing on these dynamic indexical relations may have far-reaching consequences for superdiversity as a way of making sense of language-in-society.