Nano-enhanced biolubricant in sustainable manufacturing: From processability to mechanisms

To eliminate the negative effect of traditional metal-working fluids and achieve sustainable manufacturing, the usage of nano-enhanced biolubricant (NEBL) is widely researched in minimum quantify lubrication (MQL) machining. It’s improved tool wear and surface integrity have been preliminarily verified by experimental studies. The previous review papers also concluded the major influencing factors of processability including nano-enhancer and lubricant types, NEBL concentration, micro droplet size, and so on. Nevertheless, the complex action of NEBL, from preparation, atomization, infiltration to heat transfer and anti-friction, is indistinct which limits preparation of process specifications and popularity in factories. Especially in the complex machining process, in-depth understanding is difficult and meaningful. To fill this gap, this paper concentrates on the comprehensive quantitative assessment of processability based on tribological, thermal, and machined surface quality aspects for NEBL application in turning, milling, and grinding. Then it attempts to answer mechanisms systematically considering multi-factor influence of molecular structure, physicochemical properties, concentration, and dispersion. Firstly, this paper reveals advanced lubrication and heat transfer mechanisms of NEBL by quantitative comparison with biolubricant-based MQL machining. Secondly, the distinctive filmformation, atomization, and infiltration mechanisms of NEBL, as distinguished from metal-working fluid, are clarified combining with its unique molecular structure and physical properties. Furtherly, the process optimization strategy is concluded based on the synergistic relationship analysis among process variables, physicochemical properties, machining mechanisms, and performance of NEBL. Finally, the future development directions are put forward aiming at current performance limitations of NEBL, which requires improvement on preparation and jet methods respects. This paper will help scientists deeply understand effective mechanism, formulate process specifications, and find future development trend of this technology.

The Symbolic Use of Whetstones and Their Role in Displaying Authority over Metallurgical Processes and Trade

Whetstones of the Viking Age can have a conspicuous design, but not much is understood about the specific use of more unusual specimens, or their place in rituals. This article proposes a new interpretation of whetstones, based on novel studies of a well-known whetstone from Lejre, and miniature pendants from Tissø. Our examination of the prominent whetstone from the Lejre hoard with an x-ray fluorescence (XRF) scan, did not reveal any metal traces, which suggests that it was unused. At Tissø, the find distribution of so-called stafflike pendants – made of iron, bronze, or silver – links them to a metal-working area, and since their morphology resembles full-scale whetstones we suggest that they may be symbolic, miniature whetstones. Finally, we argue that the overarching meaning of the ritual use of whetstones is more related to the authority over – and control of – metallurgical processes, as well as the trade of metal goods, and only by proxy to the smith himself.

Influence of metal working fluid on chip formation and mechanical loads in orthogonal cutting

Metal working fluids are used in machining processes of many hard-to-cut materials to increase tool life and productivity. Thereby, the metal working fluids act on the thermal and on the mechanical loads of the tool. The changing mechanical loads can mostly be attributed to the changing friction between rake face and chip and changes in the chip formation, e.g., the contact length between rake face and chip. However, analyzing those effects is challenging, since a detailed look at the chip formation process is prevented by the metal working fluid. In this paper, a novel planing test rig is presented, which enables high-speed recordings of the machining process and process force measurements while using metal working fluids. Experiments reveal that process forces are reduced with increasing pressure of the metal working fluid. However, the average friction coefficient only changes slightly, which indicates that the reduced process forces are mainly the result of reduced contact lengths between rake face and chip.

Archaeological monuments of Zangazur (Lachin district)

The settlement of people in Lachin district that located in the foothills of the Lesser Caucasus dates back to ancient times. The settlements of the district were built mainly in accordance with tribal relations. The construction of villages in the area was mainly divided into mountainous, foothill, hill-side and plain types according to the relief of the region. On the whole, since Lachin district is located in a mountainous area, the construction of villages here was also different: mainly, the houses in the district were built far apart, mostly scattered; villages with hut dwellings and those with dwellings built compact, closer to each other.The newly built bines (nomad camps or isolated farmsteads) were named after those who built them first. Although the main occupation of the district population was animal husbandry, they were also engaged in gardening, forestry and beekeeping. Archaeological and ethnographic investigations conducted in the district, clarified that the population were engaged in many handicraft areas (pottery, stone carving, metal working, etc.). At the same time, the settlements, grave monuments, churches and tombs and bridges of the district were comprehensively studied. The district located in a mountainous area, covers one town, one settlement and 125 villages.

Rare Crucible from Medieval Karelian Hillfort: Mineralogical Fingerprints of Functional Use

A rare crucible with an unusually large volume and a pot-shaped bottom was excavated at the Tiversk hillfort (late 13–14th century—1411 AD) in the North-Western Ladoga region (Russia). ICP-MS data showed that the crucible might be attributed to local technical ceramics. Because of its specific volume and shape, which are not typical for crucibles used in non-ferrous metallurgy in medieval Karelia, earlier it had been attributed to the technical ceramics used for the cementation of iron. The present research has revealed tin bronze metal alloy along with copper sulfide minerals recorded on the crucible walls, suggesting it might have been used in non-ferrous metal working. Thermal treatment of the crucible at temperatures above 1050 °C is evidenced by the heterogeneous composition of quartz, the thermal breakdown of biotite, recorded in the temper of the ceramic fabric, and Raman spectra characteristics of hematite.

Say it in Iron. Symbols of Transformation and Reproduction in the European Iron Age

The European research on iron has traditionally focused on the technical and economic aspects of iron production, However, a view of metal working in a wider regional context shows that it is generally entrenched in symbolic meaning and ritual activity. In this paper, the author employs four ethnographic case studies to show the importance of symbolic and ritual aspects of iron working and how these are intertwined with technological factors. What comes across are also the metaphorical links between pottery vessels, food, and furnaces used to produce iron. When looking at the European material, one can discern the same associations in the ftnds of cauldrons used for offerings of food as in the finds of cauldrons used for offerings of iron, such as iron weapons. The former are placed in a context ofnurturing and human reproduction, while the latter are placed in a context of destruction. This indicates the ambiguity of iron as associated with nourishment-fertility and with destruction and death

Analyzing Safety Communication in Industrial Contexts

Work in industrial contexts is confronted with various risks, which are further amplified by the trend toward Industry 4.0. Approaches are needed to examine safety communication (SC) in such changing environments. Existing studies focus on individual SC means and quantitative evaluation measures. This article proposes a qualitative approach for analyzing SC with which a process chain in a metal-working company is investigated. The results reveal that SC is implemented as a complex system of communicative means. Weaknesses in this system entail several problems at the level of both workplaces and process chains. Due to a lack of digitalization, SC does not meet the requirements of Industry 4.0. Several task areas for communication professionals are identified in optimizing SC. These include content preparation for existing SC means according to work contexts and related tasks, creating digital SC content, and increasing the companies’ resilience to novel risks.