Phase formation in molybdenum disilicide powders during in-flight induction plasma treatment

1997 ◽  
Vol 12 (5) ◽  
pp. 1315-1326 ◽  
Author(s):  
Xiaobao Fan ◽  
Takamasa Ishigaki ◽  
Yoichiro Sato
Keyword(s):  
Raw Materials ◽  
Plasma Reactor ◽  
Power Level ◽  
Molybdenum Disilicide ◽  
Hexagonal Structure ◽  
Stable Phase ◽  
Induction Plasma ◽  
Deviation From Stoichiometry ◽  
History Of ◽  
Powder Particles

In-flight modification of MoSi2 powders has been carried out by using an Ar–H2 induction plasma. Reactor pressure, powder feed rate, and plate power level were taken as the experimental parameters to alter the thermal history of the injected powder particles. Metastable hexagonal structure of β–MoSi2 is the major phase observed in the Ar–H2 induction plasma-treated molybdenum disilicide powders, while the stable phase of tetragonal structure of α–MoSi2 usually retains no less than 30 wt. %. Depending on the experimental condition and the deviation from stoichiometry in raw materials, low silicides, Mo5Si3 and Mo3Si, and free Si were observed,

Phase Formation during In-Flight Treatment of MoSi2 Powders in an R.F. Induction Plasma

1996 ◽  
Author(s):  
X. Fan ◽  
T. Ishigaki
Keyword(s):  
Raw Materials ◽  
Eutectic Reaction ◽  
Plasma Reactor ◽  
Power Level ◽  
Molybdenum Disilicide ◽  
Hexagonal Structure ◽  
Stable Phase ◽  
Experimental Conditions ◽  
Induction Plasma ◽  
History Of

Abstract The in-flight modification of MoSi2 powders has been carried out by using an Ar-H2 induction plasma. Reactor pressure, powder feed rate and plate power level were taken as the experimental parameters to alter the thermal history of the injected powder particles. Metastable hexagonal structure of P-MoSi2 is the major phase observed in the induction plasma treated molybdenum disilicide powders, the stable phase of tetragonal structure of α-MoSi2 usually retains approximately 30 wt.%. Following the change in experimental condition and the deviation from stoichiometry in raw materials, low silicides, Mo5Si3 and Mo3Si, and free Si were observed. The formation of these phases are explained in terms of metastable eutectic reaction during rapid solidification processing. The relationship between the quantities of all these phases and the experimental conditions has been discussed.

scholarly journals Possibility of Humid Municipal Wastes Hygienisation Using Gliding Arc Plasma Reactor

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 194
Author(s):  
Joanna Pawłat ◽  
Piotr Terebun ◽  
Michał Kwiatkowski ◽  
Katarzyna Wolny-Koładka
Keyword(s):  
Low Temperature ◽  
Plasma Treatment ◽  
Alternative Fuels ◽  
Raw Materials ◽  
Arc Discharge ◽  
Plasma Reactor ◽  
Municipal Waste ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Gliding Arc

Sterilization of municipal waste for a raw material for the production of refuse-derived fuel and to protect surface and ground waters against biological contamination during transfer and storage creates a lot of problems. This paper evaluates the antimicrobial potential of non-equilibrium plasma in relation to the selected groups of microorganisms found in humid waste. The proposed research is to determine whether mixed municipal waste used for the production of alternative fuels can be sterilized effectively using low-temperature plasma generated in a gliding arc discharge reactor in order to prevent water contamination and health risk for working staff. This work assesses whether plasma treatment of raw materials in several process variants effectively eliminates or reduces the number of selected groups of microorganisms living in mixed municipal waste. The presence of vegetative bacteria and endospores, mold fungi, actinobacteria Escherichia coli, and facultative pathogens, i.e., Staphylococcus spp., Salmonella spp., Shigella spp., Enterococcus faecalis and Clostridium perfringens in the tested material was microbiologically analyzed. It was found that the plasma treatment differently contributes to the elimination of various kinds of microorganisms in the analyzed raw materials. The effectiveness of sterilization depended mainly on the time of raw materials contact with low-temperature plasma. The results are very promising and require further research to optimize the proposed hygienization process.

scholarly journals Architectural ruins: geoculture of the anatomy of buildings as illustrated by Casa Ippolito, Malta

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Lino Bianco
Keyword(s):  
Material Culture ◽  
Building Materials ◽  
Raw Materials ◽  
Primary Source ◽  
Secondary Sources ◽  
Non Invasive ◽  
History Of ◽  
Aerial Vehicle ◽  
Materials Used ◽  
Building Physics

AbstractRuins are a statement on the building materials used and the construction method employed. Casa Ippolito, now in ruins, is typical of 17th-century Maltese aristocratic country residences. It represents an illustration of secondary or anthropogenic geodiversity. This paper scrutinises these ruins as a primary source in reconstructing the building’s architecture. The methodology involved on-site geographical surveying, including visual inspection and non-invasive tests, a geological survey of the local lithostratigraphy, and examination of notarial deeds and secondary sources to support findings about the building’s history as read from its ruins. An unmanned aerial vehicle was used to digitally record the parlous state of the architectural structure and karsten tubes were used to quantify the surface porosity of the limestone. The results are expressed from four perspectives. The anatomy of Casa Ippolito, as revealed in its ruins, provides a cross-section of its building history and shows two distinct phases in its construction. The tissue of Casa Ippolito—the building elements and materials—speaks of the knowledge of raw materials and their properties among the builders who worked on both phases. The architectural history of Casa Ippolito reveals how it supported its inhabitants’ wellbeing in terms of shelter, water and food. Finally, the ruins in their present state bring to the fore the site’s potential for cultural tourism. This case study aims to show that such ruins are not just geocultural remains of historical built fabric. They are open wounds in the built structure; they underpin the anatomy of the building and support insights into its former dynamics. Ruins offer an essay in material culture and building physics. Architectural ruins of masonry structures are anthropogenic discourse rendered in stone which facilitate not only the reconstruction of spaces but also places for human users; they are a statement on the wellbeing of humanity throughout history.

Metal burial: Understanding caching behaviour and contact material culture in Australia's NE Kimberley

2021 ◽  
Vol 21 (1) ◽  
pp. 28-52
Author(s):  
Sam Harper ◽  
Ian Waina ◽  
Ambrose Chalarimeri ◽  
Sven Ouzman ◽  
Martin Porr ◽  
...  
Keyword(s):  
Material Culture ◽  
Cultural Practices ◽  
Raw Materials ◽  
Cross Cultural ◽  
Contact Material ◽  
Northern Australia ◽  
Assemblage Theory ◽  
Close Proximity ◽  
History Of ◽  
Human Burials

This paper explores identity and the recursive impacts of cross-cultural colonial encounters on individuals, cultural materials, and cultural practices in 20th-century northern Australia. We focus on an assemblage of cached metal objects and associated cultural materials that embody both Aboriginal tradition and innovation. These cultural materials were wrapped in paperbark and placed within a ring of stones, a bundling practice also seen in human burials in this region. This ‘cache' is located in close proximity to rockshelters with rich, superimposed Aboriginal rock art compositions. However, the cache shelter has no visible art, despite available wall space. The site shows the utilisation of metal objects as new raw materials that use traditional techniques to manufacture a ground edge metal axe and to sharpen metal rods into spears. We contextualise these objects and their hypothesised owner(s) within narratives of invasion/contact and the ensuing pastoral history of this region. Assemblage theory affords us an appropriate theoretical lens through which to bring people, places, objects, and time into conversation.

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

scholarly journals Mineralogy and Geochemistry of Ultramafic Rocks from Rachoni Magnesite Mine, Gerakini (Chalkidiki, Northern Greece)

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 934
Author(s):  
Evangelos Tzamos ◽  
Micol Bussolesi ◽  
Giovanni Grieco ◽  
Pietro Marescotti ◽  
Laura Crispini ◽  
...  
Keyword(s):  
Raw Materials ◽  
Mining Area ◽  
Ultramafic Rocks ◽  
Northern Greece ◽  
Icp Ms ◽  
Time In Literature ◽  
History Of ◽  
First Time ◽  
The Eu

The importance of magnesite for the EU economy and industry is very high, making the understanding of their genesis for the exploration for new deposits a priority for the raw materials scientific community. In this direction, the study of the magnesite-hosting ultramafic rocks can be proved very useful. For the present study, ultramafic rock samples were collected from the magnesite ore-hosting ophiolite of the Gerakini mining area (Chalkidiki, Greece) to investigate the consecutive alteration events of the rocks which led to the metallogenesis of the significant magnesite ores of the area. All samples were subjected to a series of analytical methods for the determination of their mineralogical and geochemical characteristics: optical microscopy, XRD, SEM, EMPA, ICP–MS/OES and CIPW normalization. The results of these analyses revealed that the ultramafic rocks of the area have not only all been subjected to serpentinization, but these rocks have also undergone carbonation, silification and clay alteration. The latter events are attributed to the circulation of CO2-rich fluids responsible for the formation of the magnesite ores and locally, the further alteration of the serpentinites into listvenites. The current mineralogy of these rocks was found to be linked to one or more alteration event that took place, thus a significant contribution to the metallo- and petrogenetic history of the Gerakini ophiolite has been made. Furthermore, for the first time in literature, Fe inclusions in olivines from Greece were reported.

scholarly journals Techno-morphological features of items made of antler from the site near the village of Michnievičy (north-western Belarus)

2019 ◽  
Vol 8 (4) ◽  
pp. 116-122
Author(s):  
Anna Andreevna Malyutina ◽  
Aleksandr Nikolaevich Vashanov ◽  
Mariya Ivanovna Tkacheva ◽  
Evgenia Sergeevna Tkach
Keyword(s):  
Morphological Analysis ◽  
Raw Materials ◽  
Morphological Features ◽  
National Academy Of Sciences ◽  
History Of ◽  
The 1960S ◽  
Academy Of Sciences ◽  
The Village ◽  
North Western ◽  
Selection Of

The paper presents the results of a techno-morphological analysis of items made of antler obtained as a result of the collections from the 1960s-1990s from the site near the village of Michnievičy Smorgon District of the Grodno Region (north-western Belarus). Currently, more than 100 artifacts are known from this site, as well as a large number of fauna residues with no visible traces of processing. Radiocarbon dating was obtained for some categories of products, which link them to 9-2 thousand BC. The largest part of the collection refers to the period of the Mesolithic - Neolithic. At the first stage of work, the most expressive and numerous group of artifacts made of horn (24 exemplars), stored in the fonds of the Institute of History of the National Academy of Sciences of Belarus, was selected for a techno-morphological analysis. The degree of preservation of the external surface of objects is relatively good, which made it possible to analyze macro-traces related to the technology of manufacturing various categories of products, on the basis of which a process flow was proposed - from the selection of raw materials to the finished product. The analysis of the technological traces recorded on the products allowed us to highlight the differences in the manufacturing processes of the oldest tools. In addition, on the basis of the macro signs of utilitarian wear, preliminary observations on the functional using of objects were obtained. According to technological and morphological features, the whole of the analyzed material was divided into conditional categories of instruments with a selected heel and without it. The presence or absence of this element, apparently, influenced the method of using objects in various household situations.

scholarly journals History of research on solid electrolytes with ionic conductivity in the Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials of the KSC RAS.

2020 ◽  
Vol 11 (6-2020) ◽  
pp. 44-54
Author(s):  
Galina B. Kunshina ◽  
◽  
Vladimir. P. Kovalevsky ◽  
Keyword(s):  
Solid Electrolytes ◽  
Raw Materials ◽  
Research Direction ◽  
Mineral Raw Materials ◽  
Rare Elements ◽  
History Of Research ◽  
Start Up ◽  
History Of ◽  
Scientific Group ◽  
Academy Of Sciences

There are described the start-up and development at the I.V. Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials of the FederalResearch Centre “Kola Science Centre of the Russian Academy of Sciences”(ICTREMRM KSC RAS) studies on the synthesis of low-temperature solid electrolytes with high conductivity for Ag+, Cu+, Li+ions. The most significant results achieved by a scientific group under the leadership of PhD O.G. Gromov for almost half a century are presented. The research direction of solid electrolytes is extremely promising and in demand, and the possible fields of application of such electrolytes are constantly expanding.

scholarly journals Życie międzynarodowe rzeczy. Przedmioty luksusu i codziennego użytku w społecznej historii stosunków międzynarodowych

2018 ◽  
pp. 7-34
Author(s):  
Andrzej GAŁGANEK
Keyword(s):  
International Relations ◽  
Social History ◽  
Raw Materials ◽  
Social Systems ◽  
Social World ◽  
Advanced Technology ◽  
Prestige Goods ◽  
The Social ◽  
Uneven And Combined Development ◽  
History Of

The paper discusses the potential of objects, broadly understood luxury ‘items’ and necessities, in order to present uneven and combined development as the foundation of the social history of international relations. The author evidences that this approach to ‘objects’ allows us to achieve, at the very least, the following: (1) to observe the single social world which emerges after the division into ‘internal’ and ‘international’ is rejected; (2) to ‘touch’ the international outside the realm that the science of international relations usually associates with international politics; (3) to examine the social history of international relations, abandoning the approach that dominates in traditional historiography where production processes are privileged over consumption processes; (4) to demonstrate how human activities create internationalism. Discussing apparently different processes related to the international life of broadly understood ‘objects’, such as African giraffes, Kashmiri shawls, silk, the importance of English items for the inhabitants of Mutsamudu, or the opera Madame Butterfly the author identifies similar patterns which, although sometimes concealed, demonstrate the consequences of uneven and combined development for the social history of international relations. Prestige goods express affluence, success and power. They are usually objects manufactured from imported raw materials or materials, with limited distribution, which require a significant amount of labor or advanced technology to create. In contrast to everyday necessities, owing to their high value, prestige goods are exchanged over long distances through networks established by the elite. The analysis of manufacturing, exchange and social contexts related to prestige goods constitutes a significant source for understanding the social history of international relations. The examples in the paper present control over these goods as a source of political power. The control of raw materials, production and distribution of prestige goods is perceived as key to maintaining hierarchical social systems. Objects are inescapably related to ideas and practices. Uneven and combined development leads to meetings between people and objects, either opening or closing the space, allowing for their transfer and domestication, or rejection and destruction respectively. Concentration on the analyses of objects outside of modernization models or comparisons between civilizations and the conscious narrowing of perspective offers a tool with a heuristic potential which is interesting in the context of international relations. Comparative observation of objects (‘single’ elements of reality) via cultures undergoing uneven and combined development protects us from historiographic western exceptionalism. It also shows that the division between the ‘internal’ and ‘international’ unjustifiably splits the social world and makes it impossible to understand.

Sign in / Sign up

Export Citation Format

Share Document