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Investment casting is a widely utilized casting technique that offers superior dimensional accuracy and surface quality. In this method, the wax patterns are employed in the layer-by-layer formation of a shell mold. As is customary, the patterns were created through the injection of molten or semi-solid wax into the die. The quality of the final casting is affected by the quality of the wax pattern. Furthermore, the filling of the die with wax can be associated with die-filling challenges, such as the formation of weld lines and misruns. In this study, the injection filling of the fluidity probe die with RG20, S1235, and S1135 pattern waxes was simulated using ProCast software. The thermal properties of the waxes, including thermal conductivity, heat capacity, and density across a wide temperature range, were determined with the assistance of a laser flash analyzer, a differential scanning calorimeter, and a dynamic mechanical analyzer. A favorable comparison of the acquired properties with those reported in the literature was observed. The Carreau model, which corresponds to non-Newtonian flow, was employed, and the parameters in the Carreau viscosity equation were determined as functions of temperature. Utilizing the thermal data associated with the wax patterns and the simulation outcomes, the interfacial heat transfer coefficients between the wax and the die were ascertained, yielding a value of 275–475 W/m2K. A strong correlation was observed between the experimental and simulated filling percentages of the fluidity probe across a wide range of injection temperatures and pressures. The analysis of the simulated temperature, fraction solid, viscosity, and shear rate in the wax pattern revealed that viscosity is a crucial factor influencing the wax fluidity. It was demonstrated that waxes with an initial high viscosity exhibit a low shear rate, which subsequently increases the viscosity, thereby hindering the wax flow. [ABSTRACT FROM AUTHOR]

The notion of politeness is closely connected with communication control as one of its important mechanisms, which, however, has not been thoroughly researched in academic literature. In the present paper, we view this mechanism through the prism of communication monitoring, defined as a social negotiation instrument aimed at the speaker's self-control and regulation of other people's verbal and nonverbal behaviour. The study employs a complex of qualitative methods including observation, definition analysis, discourse analysis and introspection. Drawing upon the data of over 1500 communicative situations in English and Russian, we distinguish the prognostic, diagnostic, regulative, corrective, and reflexive functions of monitoring, as well as the function of conflict resolution. The connection between monitoring and politeness is determined by the existence of social constraints and the necessity to observe established rules and norms. The presence of multiple communication variables makes it possible to distinguish different types of monitoring: (i) horizontal vs. vertical monitoring; (ii) self-monitoring vs. monitoring of others; (iii) verbal vs. nonverbal monitoring; (iv) oral vs. written monitoring; (v) explicit vs. implicit monitoring; (vi) pre-monitoring vs. concurrent monitoring vs. post-monitoring; (vii) direct vs. mediated monitoring; and (viii) overt vs. covert monitoring. (Im)politeness is manifested in all the types through the choice of words and communication strategies, observance or violation of conversational rules, and different forms of nonverbal behaviour. These findings can lead to their practical application and help to enhance the effectiveness and quality of human interaction. [ABSTRACT FROM AUTHOR]

The use of collaborative robots (Cobots) for materials development in chemical laboratories is currently of high priority. Herein, the Cobot is used for autonomous continued analysis and synthesis of graphene oxide–polyethyleneimine‐based membrane to unify a method and prospects for big data collection are shown. Membranes have already demonstrated a selective affinity to potassium cations and promised to adjust permeability for other cations by changing pH. The Cobot allows a variation of membrane properties by its composition modification. The present strategy combines a novel perspective of material production by Cobots and the application of machine learning. Moreover, the current approach can be adapted for different modern chemical laboratories for various scientific research, and the proper workflow is provided. [ABSTRACT FROM AUTHOR]

The paper aimes to the introduction into scientific circulation of the materials of the Zhigulyovsk I settlement excavation, which was explored in 2017 by the expedition of the Agency for the Preservation of the Historical and Cultural Heritage of the Samara Region under the leadership of V.A. Tsybin. The research presents the grouping of ceramics according to external signs and description of technological characteristics of some stages of the pottery process. The technical and technological analysis of ceramics included the determination of the characteristics of the raw material, the traditions of forming paste, the nature of the surface treatment and the firing of the vessels. The materials of settlement refer to the classical variant of the southern sites of the Imenkovo culture, but in the ceramic complex there are distinguished ceramics groups that differ in appearance (external culture of the vessels) and in the manufacturing technique (internal culture of the vessels). These differences are probably related to the chronological development of pottery of Imenkovo culture and reflect both the natural evolution of pottery skills in time and the infusion of certain components at different stages of this development.

The article is devoted to the analysis of pottery traditions of the population associated with the existence of “long houses” on Staraya-Maina hillfort (Ulyanovsk Oblast), dated by the Great Migration Period. The research is based on the ceramic collection found on the hillfort during the excavations in 1990–1991. This paper presents a typological description of vessels and the results of technological analysis conducted by the author according to A. A. Bobrinsky’s method. The analysis revealed two massive pottery traditions, one of which was widely known on Imenkovo culture settlements, while the second one was a new discovery. The author suggests that this group of ceramics might be associated with an inflow of population from the Middle Oka region and from the Oka-Sura region in the fifth century AD, which brought the typical complex of garnishments of Ryazan-Oka type to the Middle Volga region.

A moderately thermophilic Gram-positive chemo-organotrophic bacterium, strain SP2, was isolated by serial dilutions with crotonate and yeast extract as substrates from a butyrate-degrading methanogenic enrichment obtained from thermophilically digested sludge of the Kuryanoskaya wastewater treatment plant (Moscow, Russia). Cells of strain SP2 are spore-forming rods, sometimes occurring in short chains. The bacterium is an obligate anaerobe that grows at temperatures from 20 to 70 °C (55–60 °C optimum) within a pH range of 3.5–8 (7.5 optimum) and with NaCl concentrations of up to 2.5%. The strain utilized yeast extract and simple sugars as carbon and energy sources. Thiosulfate was used as an electron acceptor when grown on sucrose, resulting in the formation of hydrogen sulfide and the accumulation of elemental sulfur globules inside the cells. Strain SP2 is phylogenetically related to Biomaibacter acetigenes strain SK-G1T as revealed by comparison with the 16S rRNA gene (99.9% identity) and genome (ANI 99%, dDDH 90%) of both strains. It is interesting that strain SP2 was capable of syntrophic conversion of glycerol and lactate when co-cultivated with hydrogenotrophic methanogen, which was not previously shown for the SK-G1T type of strain. The isolation and in-depth study of new facultatively syntrophic microorganisms is important for wastewater treatment ecotechnologies due to their ability to switch to an alternative source of carbon and energy and therefore greater resistance to changing environmental conditions in bioreactors. [ABSTRACT FROM AUTHOR]

In anaerobic digestion (AD), butyrate is degraded by syntrophic consortium, but can accumulate in highly loaded AD systems. The effect of butyrate on the AD process attracts much less attention than propionate or acetate. In this work, an enrichment culture of the thermophilic butyrate-oxidizing syntrophic consortium was obtained by gradually increasing the initial butyrate concentration from 20 to 170 mM. Surprisingly, even the highest butyrate concentration did not significantly inhibit the methanogenic community, and the stage of acetate degradation was the limiting overall rate of the process. At 170 mM butyrate, the bacterial community changed towards the dominance of syntrophic acetate-oxidizing (SAO) bacteria related to Syntrophaceticus (42.9%), Syntrophomonas (26.2%) and Firmicutes (26.2%), while the archaeal community experienced a sharp decrease in the abundance of Methanosarcina thermophila (from 86.0 to 25.0%) and increase in Methanothermobacter thermautotrophicus (from 3.2 to 53.1%) and Methanomassiliicoccus (from 3.2 to 21.9%). Thus, the shift from acetoclastic methanogenesis to SAO coupled to hydrogenotrophic methanogenesis occurred as an adaptive strategy to overcome high acetate (~200 mM) build-up. Bioaugmentation with the obtained enrichment culture was effective in mitigating the butyrate-dominated VFA build-up during the AD of readily biodegradable waste, increasing the methane production rate, methane yield and volatile solids removal by more than 3.5, 6.2 and 2.9 times, respectively. Our study revealed that the thermophilic butyrate-oxidizing consortia as bioaugmented culture could be the potential strategy to alleviate the high organic load and VFA stress of AD. [ABSTRACT FROM AUTHOR]

Design and engineering of novel low dimensional metamaterials allow for new applications in membrane technology, aerospace and automotive industries, architecture, robotics, medicine, and textiles. Such materials can be strong, flexible, transparent, and can be assigned with different functionalities. Here, the authors explore the possibility of 2D graphene oxide (GO) surface to guide self-assembly of 4-cyano-4'-pentylbiphenyl (5CB) molecules via multiple hydrogen bonding and their clustering in optically active phases. The encapsulation of 5CB in a 2D geometry and birefringent properties of 5CB are tuned by the regulation of interaction energy between GO surface and 5CB. Chemical reduction of GO-5CB composites results in electrically conductive reduced graphene oxide-5CB membranes which change optical properties in response to Joule heating. The sustainable approach to the design of robust and flexible optically active materials will allow the formation of other meta-materials with different functionalities for advanced applications. [ABSTRACT FROM AUTHOR]